Research Article Characteristics of Atmospheric

Research ArticleCharacteristics of Atmospheric Compositions in the BackgroundArea of Yangtze River Delta during Heavy Air Pollution Episode

Hong-Hui Xu1 Jing-Jiao Pu1 Jun He2 Jie Liu1 Bing Qi3 and Rong-Guang Du3

1Zhejiang Meteorological Science Institute Hangzhou 310008 China2Department of Chemical and Environmental Engineering University of Nottingham Ningbo China Ningbo 315100 China3Hangzhou Meteorological Bureau Hangzhou 310051 China

Correspondence should be addressed to Jing-Jiao Pu pujingjiaohotmailcom and Jun He junhenottinghameducn

Received 14 January 2016 Revised 14 March 2016 Accepted 23 March 2016

Academic Editor Jiyi Lee

Copyright copy 2016 Hong-Hui Xu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In order to understand the formation and evolution of recurrent severe haze pollution episodes in Yangtze River Delta China ashort comparative sampling campaign was conducted at the Linrsquoan background monitoring station from 25 November 2013 to 14December 2013 The characteristic concentrations of PM

25 black carbon CO

2 CO and CH

4have been systematically recorded at

the abovementioned site Coupled with detailed analysis of air backward trajectories fire spot distribution surrounding the studiedsite and meteorological impacts temporal trend diurnal variation and intercorrelation of the aforementioned species have alsobeen comprehensively investigated throughout prehaze haze and posthaze periods

1 Introduction

Due to the fast industrialization in China severe hazepollution episodes have occurred more frequently in thepast few years especially in Yangtze River Delta [1ndash4] PearlRiver Delta [5ndash7] and North China Plain [8ndash10] and theyhave attracted more and more concern because they notonly reduce atmospheric visibility but also pose great healththreats to human beings [11ndash14] A number of studies havebeen conducted to investigate the formation of haze and char-acteristics of the ambient aerosols worldwide The previousresearches found out that the formation of secondary aerosolwas one of the important mechanisms of haze occurrenceand meteorological factors including stagnant atmosphericcondition weak surface wind speed and strong temperatureinversion in the planetary boundary layer (PBL) allowingpollutants to accumulate in a shallow layer were anothermain contributor to haze episodes [3 10 15] The watersoluble components in the airborne particles could be usedto explore the key causes of haze formation in urban areas[1 8 16] In Yangtze River Delta (YRD)many researches havebeen carried out on the correlation between aerosol plus gas

concentrations (eg PM25 SO2 NO119909 CO andO

3) and other

chemical composition of these fine aerosols in order to betterunderstand the formation mechanism of haze aerosols [2ndash4 17] Fu et al [2] reported that much higher concentrationof secondary aerosol particles was observed on the heavilypolluted day and the unusual stagnant dispersion conditionplayed a predominant role in causing such a severe pollutionHuang et al [17] studied several extreme low visibility periodsby a synergy of ground-based monitoring and satellite andlidar observations and identified three typical haze typesin Shanghai that is secondary inorganic pollution dustand biomass burning Kang et al [3] found that large-scalestagnation occurred in a long-lasting haze episode in Nanjingand high ratio of NO

3

minusSO4

2minus indicated that traffic emissioncould be one of the main sources in the YRD region

It is known that the mass concentration ratios of variousatmospheric pollutants measured at the same site couldindicate their different origins such as anthropogenic andbiogenic sources [18ndash21] BC is amorphous carbon producedby incomplete combustion of carbonaceousmaterials mainlyfrom vehicle emissions industrial combustion residentialburning biomass burning power plants and so forth [22]

Hindawi Publishing CorporationAdvances in MeteorologyVolume 2016 Article ID 7240486 13 pageshttpdxdoiorg10115520167240486

2 Advances in Meteorology

CO2and CH

4are two types of important greenhouse gases

CO2primarily derives from fossil fuel combustion cement

production and land use change while CH4mainly comes

from ruminant animals wetlands rice paddies energy pro-duction landfills biomass burning and biogenic sources[23] CO is an indirect greenhouse gas which comes fromvehicle exhaust and other incomplete combustion processes[24] The correlations of concentrations of BC CO

2 and

CO showed that ΔCOΔCO2(regression slope of COCO

2)

could present combustion efficiency of emission sources andthe chief source might be identified based on the specificCOCO

2emission ratio of different emission sources [25 26]

BesidesΔBCΔCOcould also be affected by fuel compositionand the types of combustion [27ndash30] for instance the BCCOemission ratio became higher from those more carboncontained fuel when the combustion condition remained thesame as the larger BC fraction in PM

25could be produced

[31] and the emission intensity of BC and CO would differsignificantly under flaming or smoldering condition for thesame fuel (eg vegetation fire) [32] Moreover ΔBCΔCOcould imply the possible loss of BC during atmospherictransport as BC is easier to be removed by dry or wetdeposition especially in the marine boundary layer [19 3334] Atmospheric measurements of carbonaceous aerosols inChina in recent years have provided useful information abouttheir characteristics and relevant processes responsible fortheir variability and contribution to haze formation [35ndash38]However most of the reports focused on urban areas andmight not be representative sufficiently of regional condi-tions In addition very few studies inChina have attempted toevaluate the particulate and carbonaceous aerosols measuredsimultaneously with other relevant trace gaseous speciesduring heavy aerosol pollution events especially in YRDregion

Therefore in this study Global Atmospheric Watch(GAW) station of Linrsquoan regional background site has beenchosen for a short yet comparative sampling campaignbetween nonhaze and haze episodes from late Nov 2013to early Dec 2013 This location is in the suburb of LinrsquoanCity typical of nonurban environment in YRD and thecomparative sampling on this site was deemed beneficialto understanding more of regional characteristics of suchaerosols during both nonhaze and severe haze pollutionepisodes According to the air quality index (AQI) releasedby the Environmental Protection Bureau (EPB) of ZhejiangProvinceHangzhou experiencedmild haze on 1Decmoder-ate haze on 2sim3Dec and severe haze from4 to 9Dec and thehaze degraded back to mild on 10sim11 Dec During this hazeepisode the hourly mean concentration of PM

25reached up

to 394 120583gmminus3 in Hangzhou which was the highest value in2013 Compared with another polluted event which occurredin Jan 2013 this haze event persisted longer and appeared tobe much more severe [39] In this report the characteristicconcentrations of PM

25 BC CO

2 CO and CH

4have

been systematically measured in situ Coupled with detailedanalysis of air backward trajectories fire spot distributionsurrounding the studied site and meteorological impactstemporal trend diurnal variation and intercorrelation of

the abovementioned species have also been comprehensivelyinvestigated throughout prehaze haze and posthaze periodswhich could shed light on the evolution of these species andtheir important roles in the formation of such a severe hazeepisode in this regional background area

2 Experimental

21 Sampling The sampling site is located at the WMOLinrsquoan Regional Atmospheric Background Station (119∘441015840E30∘181015840N 1386masl) which is in the southern part of YangtzeRiver Delta about 60 km away to the west of Hangzhou andabout 150 km away to the southwest of Shanghai The stationis surrounded by hilly lands forest and farming areas withheavy vegetation coverage There is no large village aroundwithin 3 km The prevailing wind direction is northeast andsouthwest Special weather phenomenon rarely occurs andthe frequency of thermal inversion is low with distinct mete-orological characteristics of subtropicalmonsoon climate andatmospheric circulation

The equipment for in situ observation of PM25

wasTEOM 1405-D (Thermo Fisher Scientific)The sampling flowrate was 3 Lminminus1 and the time interval of measurement was5 minutes This monitor takes a direct mass measurement ofparticulates using a tapered element oscillating microbalance(TEOM) to measure the mass change of sample filters ontowhich particles impinge The observation instrument of BCwas Aethalometer AE-31 (American Magee Scientific) Thereare seven wavelengths that could be used for observations370 nm 470 nm 520 nm 590 nm 660 nm 880 nm and950 nm respectively The sampling flow rate was 5 Lminminus1with 25120583m impactor in the air inlet and the time intervalwas 5 minutesThe instrument aspirates ambient air using itsinlet tube and black carbon mass concentration is estimatedby measuring the change in the transmittance of a quartzfilter tape with and without particles collectedThese data areautomatically recorded in the flash card of the instrument anddisplayed on the screenThe data analyzed here was observedfrom the 880 nm channel [40] CO

2and CH

4concentra-

tions were measured by CO2CH4analyzer (Picarro G1301)

while CO concentration was measured by CO2CO analyzer

(Picarro G1302) The measuring technique is based on cavityring-down spectroscopy The device comprises three mainparts a laser a high finesse optical cavity with two or moremirrors and a photodetector The laser light is injected intothe cavity through one partially reflecting mirror This lightbuilds up over time in the cavity and is monitored by aphotodetector through a second partially reflecting mirrorAfter the laser is rapidly turned off most of the light remainstrapped in the cavity and the decaying light intensity due tocavity mirror loss as well as sample absorption and scatteringis measured The limit of detection of CO

2 CH4 and CO

measuredwith this technique is lower than 005 ppm 07 ppband 5 ppb per 5min respectively the value of maximumdrift peak reaches 05 ppm 3 ppb and 50 ppb per monthrespectively The time interval of measurement is 4 secondsThemore detailed descriptions of the whole analytical systemcan be found in Fang et al [41 42] The above five colocated

Advances in Meteorology 3

measurements were conducted simultaneously from 25 Novto 14 Dec 2013

The hourly meteorological data including visibility rela-tive humidity and surface wind speed was collected from themeteorological observation devices deployed within Linrsquoanstation Wind speed was observed at 10m above the groundand relative humidity was collected at 15m above the groundVisibility was monitored by FD12 forward scatter visibilitymeter (Vaisala Corporation Finland)

22 Quality Control For the PM25

and BC measurementsthe calibration of the flow rate was done biweekly at normalconditionHowever when it became noisy during continuousoperation the flow rate was calibrated accordingly and theoutliers were excluded from analysis

For the CO2 CH4 andCOmeasurements the calibration

of the observation system was conducted regularly every 12hours by measuring a set of standard working gases whichare traceable to WMOGAW standard gas of level one andconcentrations were corrected slightly from these calibra-tions [41 42] In addition the outliers were also excludedaccording to the equipment performance logwhen therewereinstrument troubles or anthropogenic influences such asinstrument maintenance or on-site visit

Routine maintenance for the meteorological instrumentswas carried out regularly so that the quality of observationswould not deteriorate significantly Routine quality controlchecks were also conducted to detect the equipment faults

3 Results and Discussion

31 Air Mass backward Trajectory Analysis Figure 1 illus-trated the active fire locations monitored by MODIS instru-ment on Satellite Terra (transit time in the day is around1030 local time) and Aqua (transit time in the day is around1330 local time) of USA NASA [43] and the 96 hr air massbackward trajectories of Linrsquoan station with an interval of 3hours at 500m (agl) from 25 Nov to 15 Dec were calculatedby Hysplit 49 model from NOAA (Draxler and Rolph)The input meteorological data of trajectory model was fromGlobal Data Assimilation System (GADS) of NOAA Thestatistically mean trajectories with their relative percentageshown have been adopted to represent the pathways of eachcluster for a more concise presentation by merging throughthe Euclidean calculation

During the prehaze period (25ndash30 Nov 2013) the airmass over the sampling site mainly originated from thenorthwest sector 417 of the 96 h backward trajectoriespassing through Inner Mongolia Shanxi Henan and Anhuiprovinces to Linrsquoan with the rest 583 trajectories comingthrough Gansu Ningxia Shanxi Henan and Anhui beforereaching the studied site During this period trajectorieswereobserved to pass through the north China plain with heavyindustries but fewer fire spots distributed in the northwestsector (Figure 2) During the haze period (4ndash9 Dec 2013)the 96 h backward trajectories transported much shorterdistance indicating more stagnant meteorological conditionin the surrounding area of the receptor site 575 coming

from Henan passing through Anhui and reaching Linrsquoan andanother 425 circling over Jiangxi and Zhejiang provincesin the southwest sector where the daily average number offire spots increased dramatically (Figure 2) indicating muchstronger biomass burning contribution to the air mass overthe receptor site through short-range transport In the post-haze period (10ndash14Dec 2013) themajority of airmasses orig-inated from the northwest sector while the density of fire spotsurrounding the sampling site had decreased significantly

Apparently based on both air mass backward trajectoryand fire spot distribution it could be inferred that the airquality in the studied site had been affected by the air parcelscoming from biomass burning regions via the short- andmedium-range transport particularly during the haze episodein addition to the regular industrial activities and trafficemissions

32 Temporal Trends of PM25 and BC Figure 3 shows thehourly mean mass concentration of PM

25at Linrsquoan regional

background station from 25 Nov to 14 Dec 2013 Before1 Dec 2013 the average PM

25concentration was 304 plusmn

100 120583gmminus3 lower than 75 120583gmminus3 which is the daily averagehealthy threshold for residential area and countryside definedin the latest Chinarsquos National Air Quality Standard (GB3095-2012) After that the PM

25level started to increase stayed

above 75 120583gmminus3 from 1500 on 3 Dec to 1500 on 9 Decand exceeded 250 120583gmminus3 at the periods of 1600ndash2100 on6 Dec 1100ndash2200 on 7 Dec and 1600ndash1800 on 8 Dec Itwas clearly showing that a severe haze pollution event hit thesampling site during 4sim9 Dec 2013 strongly with PM

25of

1625 plusmn 666 120583gmminus3 and the air quality in terms of particulatelevel deteriorated most from 6 to 8 Dec 2013 with PM

25

of 2033 plusmn 710 120583gmminus3 The particle concentration trend wasconsistent with the AQI published by Zhejiang ProvincialEnvironmental Protection Bureau (httpwwwzjepbgovcnhbtmhwzindexhtm) for which PM

25was also categorized

as the primary pollutant during this study periodIt can also be seen from Figure 3 that the mass ratio of

PM25

in PM10

(PM25PM10) at Linrsquoan background station

started to rise from 1 Dec 2013 with the average ratio of 636plusmn 56 during 1sim3 Dec 2013 Afterwards the mean ratioof PM

25PM10

kept on increasing and reached 707 plusmn 56during severely polluted period of 4sim9 Dec 2013 which wasnearly close to the value observed in Shanghai during anotherlarge-scale haze pollution episode that happened in YRD inJanuary 2013 [39] During the prehaze (25sim30 Nov 2013)and posthaze (10sim14 Dec 2013) periods the mean ratios ofPM25PM10were 427 plusmn 112 and 561 plusmn 67 respectively

This trend demonstrated that more PM25

had been formedand contributed to the inhalable particulatematter during theheavy haze period from 1 to 9 Dec 2013 in terms of bothmassconcentration and mass ratio of PM

25PM10 which might

explain that much stronger secondary aerosol formation andaccumulation could occur including secondary organic andinorganic aerosols during such a haze pollution event in thisstudied region [44]

Figure 4 presented the scatter distribution of hourlymeanconcentrations of BC and PM

25at Linrsquoan background station


Linrsquoan station

417

583

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(a)100∘E

575

425Linrsquoan station

46∘N

42∘N

38∘N

34∘N

30∘N

26∘N

128∘E124∘E120∘E116∘E112∘E108∘E104∘E(b)

610390

Linrsquoan station

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(c)

Figure 1 Active fire locations and 96 hr air mass backward trajectories of Linrsquoan station (a) Prehaze period (25sim30Nov 2013) (b) haze period(4sim9 Dec 2013) and (c) posthaze period (10sim14 Dec 2013)

1215

1127

1128

1129

1130

121

122

123

124

125

126

127

128

129

1210

1211

1212

1213

1214

1126

1125

Date

NorthwestSouthwest

NortheastSoutheast

0

50

100

150

200

250

Num

ber o

f fire

spot

s

Figure 2 Daily numbers of fire spots in different sectors northwest sector 100∘Endash119733∘E 303∘Nndash48∘N southwest sector 100∘Endash119733∘E22∘Nndash303∘N northeast sector 119733∘Endash130∘E 303∘Nndash48∘N and southeast sector 119733∘Endash130∘E 22∘Nndash303∘N


PM25PM10

PM25

0

50

100

150

200

250

300

350

400PM

25

mas

s con

cent

ratio

n (120583

g mminus3)

20

30

40

50

60

70

80

90

Mas

s rat

io o

fPM

25

inPM

10(

)

1126 1127 1128 1129 1130 121 122 123 124 125 126 127 128 129 1210 1211 1212 1213 12141125 1215000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000

Local time

Figure 3 Hourly mean mass concentration of PM25

and mass proportion of PM25

in PM10at Linrsquoan regional background station

during three periods prehaze period (25sim30 Nov 2013) hazeperiod (4sim9 Dec 2013) and posthaze period (10sim14 Dec2013) The temporal concentration trends of both BC andPM25

seemed very consistent and the square of correlationcoefficient of concentrations of BC and PM

25was up to

058 (prehaze period) 079 (haze period) and 086 (posthazeperiod) respectively with 99 confidence interval As for thefact that it is well known that BC is essentially a primarypollutant emitted from various combustion processes thehigh correlation coefficient of concentrations of BC andPM25

during haze period indirectly confirmed that BC wasemitted from the similar sources to those precursors whichcontributed largely to the formation of PM

25in this region

The mass ratio of BC in PM25

accounted for 803 plusmn 246699 plusmn 091 and 895 plusmn 140 in prehaze haze and posthazeperiods respectively It can be clearly seen that the massproportion of BC in PM

25was lower during haze period

which was also observed in other cities of China such asShanghai and Guangzhou where the significant increase ofsecondary species caused the haze days [6 39]

33 Temporal Trends of CO2 CO and CH4 Both CO2and

CO are directly and indirectly related with the emissionfrom combustion of fossil fuels (oil natural gas and coal)solid waste biomass (eg wood products) and with variousindustrial processes (eg cement kilns) CH

4is mainly

released through agricultural practices including livestockbiomass burning and the decay of landfill wastes though itcould also be emitted during the production and transport offossil fuels (eg natural gas)

Figure 5 describes the hourly mean concentrations ofCO2 CO and CH

4at Linrsquoan background station from 25

Nov to 14 Dec 2013 Before 1 Dec the occurrence levels ofCO2 CO and CH

4maintained their concentrations below

4207 ppm 054 ppm and 200 ppm respectively From 1Decto 3 Dec they started to increase gradually and reachedthe peak of 4296 ppm (CO

2) 082 ppm (CO) and 207 ppm

(CH4) respectively During the period of 4sim9 Dec con-

centrations of these pollutants jumped noticeably especiallyfrom 1600 on 6 Dec to 1000 on 8 Dec with the peak valuesof 4942 ppm (CO

2) 218 ppm (CO) and 245 ppm (CH

4)

respectively The occurrence levels of these three pollutantsdecreased to 4278 plusmn 96 ppm (CO

2) 078 plusmn 019 ppm (CO)

and 207 plusmn 006 ppm (CH4) during the posthaze period of 10sim

14 Dec though the haze had not degraded completely Thisoccurrence trend was generally consistent with that of PM

25

and BC mentioned above The spikes and trends of thesethree atmospheric gases during this sampling period couldbe attributed to the following factors (1) besides the regularindustrial activities the fire spots in surrounding region mayhave some effect especially during the haze period when theemission intensity could be strengthened which was verifiedby the analysis in Section 31 (2) stagnant atmosphericcondition would contribute to the stronger accumulation ofthese pollutants for which more details could be found inSection 34

34 Meteorological Effects on Temporal Trends of ConcernedPollutants During the sampling period from 25 Nov to 14Dec no precipitation was observed at Linrsquoan station and


R2 = 05791

BC = 009 lowast PM25 minus 034

0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)

80 1006020 400PM25 mass concentration (120583g mminus3)

Regression lineBC versus PM25

(a)

R2 = 07932BC = 006 lowast PM25 + 200

100 200 300 4000PM25 mass concentration (120583g mminus3)

0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)

Figure 4 Scatter distribution of hourly mean concentrations of BC and PM25

at Linrsquoan background station (a) prehaze period (b) hazeperiod and (c) posthaze period

relative humidity (RH) was lower than 80 at most of thetime The result in Figure 6 had shown a very clear temporaltrend that the visibility was mostly more than 10 km duringthe prehaze period dropped down to less than 5 km duringthe strong haze episode and improved to some extent from11 Dec 2013 It needs to be pointed out that fog occurred

during two periods of 2100 on 6 Decsim1100 on 7 Dec and2200 on 7 Decsim900 on 8 Dec when RH exceeded 80and visibility fell down below 1 km (Figure 6) The visibilityreduction could be attributed to the light extinction by bothwater vapor and haze aerosols during the above two slotsHowever due to the wet scavenging of particles by fog


`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time

Figure 5 Hourly mean concentrations of CO2 CO and CH


Wind (5ms)VisibilityRelative humidity

20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time

Figure 6 Hourly visibility relative humidity surface wind speed and wind direction at Linrsquoan station

droplets PM25

concentration dropped evidently in these twodurations while the concentrations of CO

2 CO and CH

4

presentedmuch less decrements (Figures 3 and 5) Given thatall the simultaneous measurements of these pollutants were

conducted at the same site the fog droplet size distributioncould be considered the same during the entire fog depositionprocess the discrepancy between concentration reductionsof particle and the other three gases might be because the


50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N

KMAASFE0600UTC DEC 2013

Surface pressure (hPa)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)

Korea Meteorological Administration (KMA)

160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

Figure 7 Surface weather patterns over eastern Asia at 0800 (local time) on 6 7 8 and 9 Dec 2013 (from httpwebkmagokr)

particle wet scavenging efficiency would be much moredominant than that of CO

2 CO and CH

4as the latter is

generally affected by gas dissolution and surface adsorption[45 46]

Similar to those reported in previous studies [2 10 15 17]weak surface wind speed was also observed at Linrsquoan stationduring this strong haze event The average wind speed was157 plusmn 084m sminus1 from 0000 on 4 Dec to 0800 on 9 Decit was lower than 210 plusmn 125m sminus1 in prehaze period from0000 on 25 Nov to 2300 on 30 Nov and it remainedat the level of 148 plusmn 087m sminus1 in posthaze period from0000 on 10 Dec to 2300 on 14 Dec (Figure 6) A weaksurface high-pressure system persisted in YRD from 4 to 6Dec 2013 (Figure 7) and at 0800 in the morning thermalinversion was observed under 200masl (Figure 8) so that theweather condition was disadvantageous for dispersion On 7Dec surface high-pressure system became weaker and on8 Dec saddle ground pressure field controlled this regionthermal inversion occurred between 200 and 800masl so

the dispersion condition remained poor From 0800 on 9Dec a strong Mongolia anticyclone came over thus thesurface wind speed increased significantly and the thermalinversion disappeared which were deemed to benefit thedispersion and circulation of atmospheric pollutants so thattheir occurrence levels dropped considerably as shown inFigures 3 and 5

35 Diurnal Variation of CO2 CO CH4 BC and PM25Figure 9 demonstrated the diurnal variation of concentra-tions of CO

2 CO CH

4 BC and PM

25between prehaze

(25sim30 Nov 2013) and strong haze (4sim9 Dec 2013) periodsIn prehaze period the diurnal variations of CO

2 BC and

PM25

seemed to be significant with the diurnal amplitudesof 104 ppm (CO

2) 24 120583gmminus3 (BC) and 177 120583gmminus3 (PM

25)

respectively while the diurnal amplitudes of CO and CH4

were only 010 ppm and 0036 ppm respectively though thediurnal variations were still slightly observable The diurnal


minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec

Figure 8 Temperature soundings at Hangzhou station at 0800 (local time) on 4sim9 Dec 2013 (from httpweatheruwyoeduupperairsoundinghtml)

distribution of CO2concentration showed a single-peak pat-

ternwith the peak value occurring at 800 CH4concentration

exhibited double peaks at 900 and 2200 BC and PM25

concentrations presented three peaks appearing at 900 1800and 2300 The diurnal CO

2distribution in prehaze period

was similar to the observations during winter season at thisstation in 2009sim2011 [42] which indicated that the diurnalCO2variation was affected predominantly by meteorological

dispersion conditions and sourcessinks [42 47] Due tothe active photosyntheticrespiration fluxes in all seasons atLinrsquoan station the minimum concentration appeared in theafternoon when the diffusion condition was more favorableand the photosynthetic CO

2uptake was strong while the

higher concentration appeared at dawn when the boundarylayer became stable and the respiration was strong Thediurnal variations of CH

4 BC and PM

25were also consistent

with the diurnal cycle of the boundary layer which led to apeak in the morning and a minimum value in the afternoonMoreover due to the anthropogenic sources especially fromthe vehicular emission at the morning and evening rushhours the concentrations of CO BC and PM

25presented

dual peaks at 900 and 1800 respectively which was similarto that observed at other locations [4 48] CH

4had not

shown that peak in the afternoon possibly because of the pho-tochemical reaction induced by OH∙ [41] At 2200sim2300the concentrations of CH

4 CO BC and PM

25presented

another peak which might be ascribed to high accumulationrates at nighttime [49] after that due to the decrease ofanthropogenic emissions the concentrations declined untilearly morning though the mixing height and wind speedremained constant and low [50]

During strong haze period more significant diurnalvariations were observed The concentrations of all these

five pollutants jumped dramatically during each hour of theday and the diurnal amplitude rose up to 164 ppm (CO

2)

033 ppm (CO) 0086 ppm (CH4) 69 120583gmminus3 (BC) and

1066 120583gmminus3 (PM25) respectively The diurnal distributions

of these pollutants displayed a trimodal pattern reachingthe peak value at 900sim1000 1700sim1800 and 2100sim2200respectively with the maximum value occurring at 1700sim1800 and the minimum value occurring at 500sim600 exceptfor CO

2whose minimum value still occurred at 1500

It is understandable that CO2concentration reached the

minimum in the afternoon which was the same as in theprehaze period due to the stronger photosynthesis uptakeduring that time For CO CH

4 BC and PM

25 the mini-

mum concentrations occurred in the early morning whichcould be explained by the fact that the emission intensityof these pollutants could be much lesser during the latenighttime It was also clear that the occurrence levels of thesefour pollutants had been increased considerably from earlymorning to midnight This trend could be also attributedto stronger industrial activities traffic emission and lesserfavorable dispersion conditions In addition it could not beignored that the regional short- andmedium-range transporthad contributed to the peaking of these four pollutants in theafternoon

36 Correlation of CO2 CO CH4 and BC Table 1 exhibitedthe correlation coefficient of concentrations of BC COCO2 and CH

4 It was manifestly seen that the correlation

coefficient in haze period was significantly higher than thatin prehaze period which was also observed at Mt FujiJapan during smoke event [19] The concentrations of BCCO CO

2 and CH

4seemed to experience a more similar

evolution in haze period ΔCOΔCO2(slope of hourly mean


Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)

Figure 9 Diurnal concentration variations of CO2 CO CH

4 BC and PM

25at Linrsquoan regional background station

concentrations of CO and CO2) and ΔCH

4ΔCO

2in haze

period were higher than those in prehaze period Generallyhigher ΔCOΔCO

2indicated relatively lower combustion

efficiency and it is also known that the combustion effi-ciency of biomass burning is normally lower than that of

fossil fuel as biomass burning is more of smoldering fires[25] In addition modified combustion efficiency (MCEdefined as ΔCO

2ΔCO + ΔCO

2) has been adopted and it

shows that MCE in haze episode (0979) was also lowerthan that in prehaze period (0985) Streets et al [51] had


Table 1 Correlation coefficient (CC) of concentrations of BCCO CO

2 and CH

4and the ratio of ΔBCΔCO ΔCOΔCO

2 and

ΔCH4ΔCO

2at Linrsquoan station

Prehaze period Haze periodCC between BC and CO 05346 07534CC between CO and CO

2

07922 09599CC between CH

4and CO

2

05769 09460ΔBCΔCO (120583gmminus3120583gmminus3) 00075 00058ΔCOΔCO

2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001

reported the emission ratio of CH4CO2derived from the

emission inventory compiled in 2000 was 180 (GgTg)from biomass burning higher than 138 (GgTg) from fossilfuel combustion in YRD The ΔBCΔCO ratio in prehazeperiod was 00075 120583gmminus3120583gmminus3 close to the value of0008 120583gmminus3120583gmminus3 in northern China in 2005 [52] whilein haze period the ratio dropped to 00058120583gmminus3120583gmminus3Smoldering biomass burning in YRD region is known to bedominant During the haze period significantly additionalCO and BC could be emitted due to the incomplete biomassburning while more BC might have been removed via wetscavenging process by fog droplets through the internal mix-ture with water soluble species when the air masses had beenlong transported [19] leading to lower ΔBCΔCO ratio inthe haze episode Consistent with the findings from air massbackward trajectory analysisΔCOΔCO

2 ΔCH

4ΔCO

2 and

ΔBCΔCO all therefore implied that the biomass burning inthis region had contributed more to the formation of hazeoccurring during 4ndash9 Dec 2013

4 Conclusion

Air mass backward trajectory and fire spot distributionshowed that mediumlong range transboundary transport ofairmasses coming frombiomass burning regions contributedto the formation of haze aerosols in Linrsquoan on 4sim9 Dec 2013when a heavy air pollution attacked Yangtze River DeltaChina The stagnant meteorological conditions includinglow surface wind speed thermal inversion in planetaryboundary layer and weak high-pressure system attributedto the accumulation of pollutants in haze period HigherPM25

mass concentration and mass ratio of PM25PM10

inhaze period indicated more PM

25had been formed and con-

tributed to the inhalable particulatematter during such a hazepollution event in this region Lower mass ratio of BCPM

25

in haze period might explain that much more secondaryaerosol had been formed and accumulated

In haze period due to the influence of stronger industrialactivities traffic emission lesser favorable dispersion con-ditions and regional transboundary transport the diurnalvariation of CO

2 COCH

4 BC and PM

25concentration pre-

sented a similar distribution displaying a trimodal patternThe correlation analysis of concentrations of CO

2 CO CH

4

and BC indicated that biomass burning might play a role

in this polluted episode The lower correlation coefficient ofBC and CO than that of CO and CO

2 CH4and CO

2in

haze period suggested more BC could be possibly removedthrough wet scavenging process by fog droplets on 6sim8 Dec

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

The authors express their great thanks to the staff of LinrsquoanRegional Atmospheric Background Station who have con-tributed to observations of greenhouse gases and the staff ofkey laboratory for atmospheric chemistry (CMA) who per-formed calibration and quality control of the data This workwas jointly supported by the ldquoStrategic Priority ResearchProgram (B)rdquo of the Chinese Academy of Sciences (Grant noXDB05020403) the China Special Fund for MeteorologicalResearch in the Public Interest (no GYHY201206011) Chi-nese National Natural Science Foundation (41303091) Zhe-jiang Meteorological Science project (2013ZD06) ZhejiangProvincial Applied Research Program for CommonwealTechnology project (2015C33011) Ningbo Municipal NaturalScience Foundation (2014A610096) and Ningbo MunicipalKey Project (2012B10042)

References

[1] H H Du L D Kong T T Cheng et al ldquoInsights into sum-mertime haze pollution events over Shanghai based on onlinewater-soluble ionic composition of aerosolsrdquoAtmospheric Envi-ronment vol 45 no 29 pp 5131ndash5137 2011

[2] Q Y Fu G S Zhuang J Wang et al ldquoMechanism of formationof the heaviest pollution episode ever recorded in the YangtzeRiverDelta ChinardquoAtmospheric Environment vol 42 no 9 pp2023ndash2036 2008

[3] H Q Kang B Zhu J F Su H Wang Q Zhang and F WangldquoAnalysis of a long-lasting haze episode in Nanjing ChinardquoAtmospheric Research vol 120-121 pp 78ndash87 2013

[4] Z-M Xiao Y-F Zhang S-M Hong et al ldquoEstimation of themain factors influencing haze based on a long-term monitor-ing campaign in Hangzhou Chinardquo Aerosol and Air QualityResearch vol 11 no 7 pp 873ndash882 2011

[5] Z Y Chen W Q Liu B Heese et al ldquoAerosol optical prop-erties observed by combined Raman-elastic backscatter lidarin winter 2009 in Pearl River Delta south Chinardquo Journal ofGeophysical Research vol 119 no 5 pp 2496ndash2510 2014

[6] J H Tan J C Duan K B He et al ldquoChemical characteristicsof PM

25during a typical haze episode in Guangzhourdquo Journal

of Environmental Sciences vol 21 no 6 pp 774ndash781 2009[7] G Zhang X Bi L Y Chan XWang G Sheng and J Fu ldquoSize-

segregated chemical characteristics of aerosol during haze inan urban area of the Pearl River Delta region Chinardquo UrbanClimate vol 4 pp 74ndash84 2013

[8] Z Q Sun Y J Mu Y J Liu and L Shao ldquoA comparison studyon airborne particles during haze days and non-haze days inBeijingrdquo Science of the Total Environment vol 456-457 pp 1ndash82013


[9] W Xu H Chen D Li F Zhao and Y Yang ldquoA case studyof aerosol characteristics during a haze episode over BeijingrdquoProcedia Environmental Sciences vol 18 pp 404ndash411 2013

[10] X J Zhao P S Zhao J Xu et al ldquoAnalysis of a winter regionalhaze event and its formation mechanism in the North ChinaPlainrdquo Atmospheric Chemistry and Physics vol 13 no 11 pp5685ndash5696 2013

[11] C K Chan and X H Yao ldquoAir pollution in mega cities inChinardquo Atmospheric Environment vol 42 no 1 pp 1ndash42 2008

[12] DChang Y Song andB Liu ldquoVisibility trends in sixmegacitiesin China 1973ndash2007rdquo Atmospheric Research vol 94 no 2 pp161ndash167 2009

[13] I Mordukhovich E Wilker H Suh et al ldquoBlack carbon expo-sure oxidative stress genes and blood pressure in a repeated-measures studyrdquo Environmental Health Perspectives vol 117 no11 pp 1767ndash1772 2009

[14] M Lodovici and E Bigagli ldquoOxidative stress and air pollutionexposurerdquo Journal of Toxicology vol 2011 Article ID 487074 9pages 2011

[15] J Quan Q Zhang HHe J LiuMHuang andH Jin ldquoAnalysisof the formation of fog and haze in North China Plain (NCP)rdquoAtmospheric Chemistry and Physics vol 11 no 15 pp 8205ndash8214 2011

[16] W J Li L Y Shao and P R Buseck ldquoHaze types in Beijingand the influence of agricultural biomass burningrdquoAtmosphericChemistry and Physics vol 10 no 17 pp 8119ndash8130 2010

[17] K Huang G Zhuang Y Lin et al ldquoTypical types and formationmechanisms of haze in an Eastern Asia megacity ShanghairdquoAtmospheric Chemistry and Physics vol 12 no 1 pp 105ndash1242012

[18] V T F Cheung and T Wang ldquoObservational study of ozonepollution at a rural site in the Yangtze Delta of ChinardquoAtmospheric Environment vol 35 no 29 pp 4947ndash4958 2001

[19] N Kaneyasu Y Igarashi Y Sawa et al ldquoChemical and opticalproperties of 2003 Siberian forest fire smoke observed at thesummit of Mt Fuji Japanrdquo Journal of Geophysical ResearchAtmospheres vol 112 no 13 Article ID D13214 2007

[20] T W Kirchstetter T Novakov P V Hobbs and B MagildquoAirborne measurements of carbonaceous aerosols in southernAfrica during the dry biomass burning seasonrdquo Journal ofGeophysical Research D Atmospheres vol 108 no 13 pp 1ndash122003

[21] A P Sullivan A S Holden L A Patterson et al ldquoA method forsmoke marker measurements and its potential application fordetermining the contribution of biomass burning fromwildfiresand prescribed fires to ambient PM

25organic carbonrdquo Journal

of Geophysical Research Atmospheres vol 113 no 22 Article IDD22302 2008

[22] Y Qin and S D Xie ldquoSpatial and temporal variation ofanthropogenic black carbon emissions in China for the period1980ndash2009rdquo Atmospheric Chemistry and Physics vol 12 no 11pp 4825ndash4841 2012

[23] P Forster V Ramaswamy P Artaxo et al ldquoChanges in atmo-spheric constituents and in radiative forcingrdquo inClimate Change2007The Physical Science Basis Contribution ofWorking Group1 to the Fourth Assessment Report of the Intergovernmental Panelon Climate Change pp 511ndash513 Cambridge University PressCambridge UK 2007

[24] S Sathitkunarat P Wongwises R Pan-Aram and M ZhangldquoCarbon monoxide emission and concentration models forChiang Mai urban areardquo Advances in Atmospheric Sciences vol23 no 6 pp 901ndash908 2006

[25] R J Yokelson I T Bertschi T J Christian P V Hobbs D EWard and W M Hao ldquoTrace gas measurements in nascentaged and cloud-processed smoke from African savanna firesby airborne Fourier transform infrared spectroscopy (AFTIR)rdquoJournal of Geophysical Research vol 108 no 13 2003

[26] N Takegawa Y Kondo M Koike et al ldquoRemoval of NOx andNOy in Asian outflow plumes aircraft measurements over thewestern Pacific in Januray 2002rdquo Journal of Geophysical ResearchD Atmospheres vol 109 no 23 pp 1ndash16 2004

[27] S Han Y Kondo N Oshima et al ldquoTemporal variations ofelemental carbon in Beijingrdquo Journal of Geophysical Researchvol 114 no 23 2009

[28] Y Kondo Y Komazaki Y Miyazaki et al ldquoTemporal variationsof elemental carbon in Tokyordquo Journal of Geophysical Researchvol 111 no 12 2006

[29] S Song Y Wu J Xu et al ldquoBlack carbon at a roadside sitein Beijing temporal variations and relationships with carbonmonoxide and particle number size distributionrdquo AtmosphericEnvironment vol 77 pp 213ndash221 2013

[30] Y Wang X Wang Y Kondo M Kajino J W Munger andJ Hao ldquoBlack carbon and its correlation with trace gases at arural site in Beijing top-down constraints from ambient mea-surements on bottom-up emissionsrdquo Journal of GeophysicalResearch vol 116 no 24 2011

[31] X H Zhou J Gao T Wang W Wu and W Wang ldquoMea-surement of black carbon aerosols near two Chinese megaci-ties and the implications for improving emission inventoriesrdquoAtmospheric Environment vol 43 no 25 pp 3918ndash3924 2009

[32] T R Zhang J W Martin C G David et al ldquoNew field-basedagricultural biomass burning trace gas PM

25 and black carbon

emission ratios and factorsmeasured in situ at crop residue firesin EasternChinardquoAtmospheric Environment vol 121 pp 22ndash342015

[33] Y Kondo N Oshima M Kajino et al ldquoEmissions of blackcarbon in East Asia estimated from observations at a remotesite in the East China Seardquo Journal of Geophysical Research vol116 no 16 2011

[34] S P Seung M S Bae J J Schauer et al ldquoEvaluation of theTMO and TOT methods for OC and EC measurements andtheir characteristics in PM25 at an urban site of Korea duringACE-Asiardquo Atmospheric Environment vol 39 no 28 pp 5101ndash5112 2005

[35] F Wang Z Guo T Lin and N L Rose ldquoSeasonal variationof carbonaceous pollutants in PM

25at an urban lsquosupersitersquo in

Shanghai Chinardquo Chemosphere vol 146 pp 238ndash244 2016[36] D S Ji J K Zhang J He et al ldquoCharacteristics of atmospheric

organic and elemental carbon aerosols in urban Beijing ChinardquoAtmospheric Environment vol 125 pp 293ndash306 2016

[37] Y Morino T Ohara J Xu et al ldquoDiurnal variations of fossiland nonfossil carbonaceous aerosols in Beijingrdquo AtmosphericEnvironment vol 122 pp 349ndash356 2015

[38] J Liu J Li Y Zhang et al ldquoSource apportionment using radio-carbon and organic tracers for PM

25carbonaceous aerosols in

Guangzhou South China contrasting local- and regional-scaleHaze eventsrdquo Environmental Science and Technology vol 48 no20 pp 12002ndash12011 2014

[39] M Zhou C Chen L Qiao et al ldquoThe chemical characteristicsof particulate matters in Shanghai during heavy air pollutionepisode in Central and Eastern China in January 2013rdquo ActaScientiae Circumstantiae vol 33 no 11 pp 3118ndash3126 2013


[40] A D A Hansen The Aethalometer Operating Manual 2005httpwwwmageescicom imagesstoriesdocsAethalometerbook 20050703pdf

[41] S-X Fang L-X Zhou K A Masarie L Xu and C W RellaldquoStudy of atmospheric CH

4mole fractions at threeWMOGAW

stations in Chinardquo Journal of Geophysical Research Atmospheresvol 118 no 10 pp 4874ndash4886 2013

[42] S X Fang L X Zhou P P Tans et al ldquoIn situ measurementof atmospheric CO

2at the fourWMOGAW stations in Chinardquo

Atmospheric Chemistry and Physics vol 14 no 5 pp 2541ndash25542014

[43] L Giglio J Descloitres C O Justice and Y J KaufmanldquoAn enhanced contextual fire detection algorithm for MODISrdquoRemote Sensing of Environment vol 87 no 2-3 pp 273ndash2822003

[44] R-J Huang Y L Zhang C Bozzetti et al ldquoHigh secondaryaerosol contribution to particulate pollution during haze eventsin Chinardquo Nature vol 514 pp 218ndash222 2014

[45] J He and R Balasubramanian ldquoRain-aerosol coupling inthe tropical atmosphere of Southeast Asia distribution andscavenging ratios ofmajor ionic speciesrdquo Journal of AtmosphericChemistry vol 60 no 3 pp 205ndash220 2008

[46] J He and R Balasubramanian ldquoA study of precipitation scav-enging of semivolatile organic compounds in a tropical areardquoJournal of Geophysical Research Atmospheres vol 114 no 12Article ID D12201 2009

[47] F Artuso P Chamard S Piacentino et al ldquoInfluence oftransport and trends in atmospheric CO

2at Lampedusardquo

Atmospheric Environment vol 43 no 19 pp 3044ndash3051 2009[48] X Zhao X Zhang X Xu J Xu W Meng andW Pu ldquoSeasonal

and diurnal variations of ambient PM25

concentration in urbanand rural environments in Beijingrdquo Atmospheric Environmentvol 43 no 18 pp 2893ndash2900 2009

[49] L Gao R Zhang Z Han et al ldquoA modeling study of a typicalwinter PM

25pollution episode in a city in Eastern Chinardquo

Aerosol and Air Quality Research vol 14 no 1 pp 311ndash322 2014[50] S Tiwari A K Srivastava D S Bisht P Parmita M K

Srivastava and S D Attri ldquoDiurnal and seasonal variationsof black carbon and PM

25over New Delhi India influence

of meteorologyrdquo Atmospheric Research vol 125-126 pp 50ndash622013

[51] D G Streets T C Bond G R Carmichael et al ldquoAn inventoryof gaseous and primary aerosol emissions in Asia in the year2000rdquo Journal of Geophysical Research vol 108 no 21 2003

[52] C Li L TMarufu R R Dickerson et al ldquoIn situmeasurementsof trace gases and aerosol optical properties at a rural sitein northern China during East Asian Study of TroposphericAerosols an International Regional Experiment 2005rdquo Journalof Geophysical Research Atmospheres vol 112 no 22 Article IDD22S04 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ClimatologyJournal of

EcologyInternational Journal of


EarthquakesJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Mining


Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal of

Geophysics

OceanographyInternational Journal of


Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal ofPetroleum Engineering


GeochemistryHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Atmospheric SciencesInternational Journal of


OceanographyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in


MineralogyInternational Journal of


MeteorologyAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Paleontology JournalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Geological ResearchJournal of


Geology Advances in


CO2and CH

4are two types of important greenhouse gases

CO2primarily derives from fossil fuel combustion cement

production and land use change while CH4mainly comes

from ruminant animals wetlands rice paddies energy pro-duction landfills biomass burning and biogenic sources[23] CO is an indirect greenhouse gas which comes fromvehicle exhaust and other incomplete combustion processes[24] The correlations of concentrations of BC CO

2 and

CO showed that ΔCOΔCO2(regression slope of COCO

2)

could present combustion efficiency of emission sources andthe chief source might be identified based on the specificCOCO

2emission ratio of different emission sources [25 26]

BesidesΔBCΔCOcould also be affected by fuel compositionand the types of combustion [27ndash30] for instance the BCCOemission ratio became higher from those more carboncontained fuel when the combustion condition remained thesame as the larger BC fraction in PM

25could be produced

[31] and the emission intensity of BC and CO would differsignificantly under flaming or smoldering condition for thesame fuel (eg vegetation fire) [32] Moreover ΔBCΔCOcould imply the possible loss of BC during atmospherictransport as BC is easier to be removed by dry or wetdeposition especially in the marine boundary layer [19 3334] Atmospheric measurements of carbonaceous aerosols inChina in recent years have provided useful information abouttheir characteristics and relevant processes responsible fortheir variability and contribution to haze formation [35ndash38]However most of the reports focused on urban areas andmight not be representative sufficiently of regional condi-tions In addition very few studies inChina have attempted toevaluate the particulate and carbonaceous aerosols measuredsimultaneously with other relevant trace gaseous speciesduring heavy aerosol pollution events especially in YRDregion

Therefore in this study Global Atmospheric Watch(GAW) station of Linrsquoan regional background site has beenchosen for a short yet comparative sampling campaignbetween nonhaze and haze episodes from late Nov 2013to early Dec 2013 This location is in the suburb of LinrsquoanCity typical of nonurban environment in YRD and thecomparative sampling on this site was deemed beneficialto understanding more of regional characteristics of suchaerosols during both nonhaze and severe haze pollutionepisodes According to the air quality index (AQI) releasedby the Environmental Protection Bureau (EPB) of ZhejiangProvinceHangzhou experiencedmild haze on 1Decmoder-ate haze on 2sim3Dec and severe haze from4 to 9Dec and thehaze degraded back to mild on 10sim11 Dec During this hazeepisode the hourly mean concentration of PM

25reached up

to 394 120583gmminus3 in Hangzhou which was the highest value in2013 Compared with another polluted event which occurredin Jan 2013 this haze event persisted longer and appeared tobe much more severe [39] In this report the characteristicconcentrations of PM

25 BC CO

2 CO and CH

4have

been systematically measured in situ Coupled with detailedanalysis of air backward trajectories fire spot distributionsurrounding the studied site and meteorological impactstemporal trend diurnal variation and intercorrelation of

the abovementioned species have also been comprehensivelyinvestigated throughout prehaze haze and posthaze periodswhich could shed light on the evolution of these species andtheir important roles in the formation of such a severe hazeepisode in this regional background area

2 Experimental

21 Sampling The sampling site is located at the WMOLinrsquoan Regional Atmospheric Background Station (119∘441015840E30∘181015840N 1386masl) which is in the southern part of YangtzeRiver Delta about 60 km away to the west of Hangzhou andabout 150 km away to the southwest of Shanghai The stationis surrounded by hilly lands forest and farming areas withheavy vegetation coverage There is no large village aroundwithin 3 km The prevailing wind direction is northeast andsouthwest Special weather phenomenon rarely occurs andthe frequency of thermal inversion is low with distinct mete-orological characteristics of subtropicalmonsoon climate andatmospheric circulation

The equipment for in situ observation of PM25

wasTEOM 1405-D (Thermo Fisher Scientific)The sampling flowrate was 3 Lminminus1 and the time interval of measurement was5 minutes This monitor takes a direct mass measurement ofparticulates using a tapered element oscillating microbalance(TEOM) to measure the mass change of sample filters ontowhich particles impinge The observation instrument of BCwas Aethalometer AE-31 (American Magee Scientific) Thereare seven wavelengths that could be used for observations370 nm 470 nm 520 nm 590 nm 660 nm 880 nm and950 nm respectively The sampling flow rate was 5 Lminminus1with 25120583m impactor in the air inlet and the time intervalwas 5 minutesThe instrument aspirates ambient air using itsinlet tube and black carbon mass concentration is estimatedby measuring the change in the transmittance of a quartzfilter tape with and without particles collectedThese data areautomatically recorded in the flash card of the instrument anddisplayed on the screenThe data analyzed here was observedfrom the 880 nm channel [40] CO

2and CH

4concentra-

tions were measured by CO2CH4analyzer (Picarro G1301)

while CO concentration was measured by CO2CO analyzer

(Picarro G1302) The measuring technique is based on cavityring-down spectroscopy The device comprises three mainparts a laser a high finesse optical cavity with two or moremirrors and a photodetector The laser light is injected intothe cavity through one partially reflecting mirror This lightbuilds up over time in the cavity and is monitored by aphotodetector through a second partially reflecting mirrorAfter the laser is rapidly turned off most of the light remainstrapped in the cavity and the decaying light intensity due tocavity mirror loss as well as sample absorption and scatteringis measured The limit of detection of CO

2 CH4 and CO

measuredwith this technique is lower than 005 ppm 07 ppband 5 ppb per 5min respectively the value of maximumdrift peak reaches 05 ppm 3 ppb and 50 ppb per monthrespectively The time interval of measurement is 4 secondsThemore detailed descriptions of the whole analytical systemcan be found in Fang et al [41 42] The above five colocated





















25of


25




PM25

in PM10



25PM10




25PM10 which might





Linrsquoan station

417

583

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(a)100∘E

575


46∘N

42∘N

38∘N

34∘N

30∘N

26∘N

128∘E124∘E120∘E116∘E112∘E108∘E104∘E(b)

610390

Linrsquoan station

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(c)


1215

1127

1128

1129

1130

121

122

123

124

125

126

127

128

129

1210

1211

1212

1213

1214

1126

1125

Date

NorthwestSouthwest

NortheastSoutheast

0

50

100

150

200

250

Num

ber o

f fire

spot

s



PM25PM10

PM25

0

50

100

150

200

250

300

350

400PM

25

mas

s con

cent

ratio

n (120583

g mminus3)

20

30

40

50

60

70

80

90

Mas

s rat

io o

fPM

25

inPM

10(

)

1126 1127 1128 1129 1130 121 122 123 124 125 126 127 128 129 1210 1211 1212 1213 12141125 1215000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000

Local time






25was up to



25in this region







4is mainly











4)





25




R2 = 05791


0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)



(a)

R2 = 07932BC = 006 lowast PM25 + 200


0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)






`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in





















25of


25




PM25

in PM10



25PM10




25PM10 which might





Linrsquoan station

417

583

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(a)100∘E

575


46∘N

42∘N

38∘N

34∘N

30∘N

26∘N

128∘E124∘E120∘E116∘E112∘E108∘E104∘E(b)

610390

Linrsquoan station

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(c)


1215

1127

1128

1129

1130

121

122

123

124

125

126

127

128

129

1210

1211

1212

1213

1214

1126

1125

Date

NorthwestSouthwest

NortheastSoutheast

0

50

100

150

200

250

Num

ber o

f fire

spot

s



PM25PM10

PM25

0

50

100

150

200

250

300

350

400PM

25

mas

s con

cent

ratio

n (120583

g mminus3)

20

30

40

50

60

70

80

90

Mas

s rat

io o

fPM

25

inPM

10(

)

1126 1127 1128 1129 1130 121 122 123 124 125 126 127 128 129 1210 1211 1212 1213 12141125 1215000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000

Local time






25was up to



25in this region







4is mainly











4)





25




R2 = 05791


0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)



(a)

R2 = 07932BC = 006 lowast PM25 + 200


0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)






`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


Linrsquoan station

417

583

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(a)100∘E

575


46∘N

42∘N

38∘N

34∘N

30∘N

26∘N

128∘E124∘E120∘E116∘E112∘E108∘E104∘E(b)

610390

Linrsquoan station

104∘E 108∘E 112∘E 116∘E 120∘E 128∘E124∘E100∘E

26∘N

30∘N

34∘N

38∘N

42∘N

46∘N

(c)


1215

1127

1128

1129

1130

121

122

123

124

125

126

127

128

129

1210

1211

1212

1213

1214

1126

1125

Date

NorthwestSouthwest

NortheastSoutheast

0

50

100

150

200

250

Num

ber o

f fire

spot

s



PM25PM10

PM25

0

50

100

150

200

250

300

350

400PM

25

mas

s con

cent

ratio

n (120583

g mminus3)

20

30

40

50

60

70

80

90

Mas

s rat

io o

fPM

25

inPM

10(

)

1126 1127 1128 1129 1130 121 122 123 124 125 126 127 128 129 1210 1211 1212 1213 12141125 1215000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000

Local time






25was up to



25in this region







4is mainly











4)





25




R2 = 05791


0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)



(a)

R2 = 07932BC = 006 lowast PM25 + 200


0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)






`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


PM25PM10

PM25

0

50

100

150

200

250

300

350

400PM

25

mas

s con

cent

ratio

n (120583

g mminus3)

20

30

40

50

60

70

80

90

Mas

s rat

io o

fPM

25

inPM

10(

)

1126 1127 1128 1129 1130 121 122 123 124 125 126 127 128 129 1210 1211 1212 1213 12141125 1215000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000

Local time






25was up to



25in this region







4is mainly











4)





25




R2 = 05791


0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)



(a)

R2 = 07932BC = 006 lowast PM25 + 200


0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)






`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


R2 = 05791


0

2

4

6

8

10BC

conc

entr

atio

n (120583

g mminus3)



(a)

R2 = 07932BC = 006 lowast PM25 + 200


0

6

12

18

24

30

BC co

ncen

trat

ion

(120583g m

minus3)


(b)

R2 = 08575


0

5

10

15

20

BC co

ncen

trat

ion

(120583g m

minus3)



(c)






`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


`

COCH4

CO2

360

400

440

480

520CO

2co

ncen

trat

ion

(ppm

)

00

05

10

15

20

25

30

CO C

H4

conc

entr

atio

n (p

pm)

1214 121512131212121112101291281271261251241231221211130112911281126 11271125000 000000000000000000000000000000000000000000000000000000 000000

Local time




20

40

60

80

100

Relat

ive h

umid

ity (

)

0

5000

10000

15000

25000

30000

20000

35000

Visib

ility

(m)

20131129 2013123 2013127 20131211 2013121520131125Local time


droplets PM25


2 CO and CH

4




50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 06 DEC 2013 (09KST 06 DEC 2013)

00UTC 06 DEC 2013 (09KST 06 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 07 DEC 2013 (09KST 07 DEC 2013)

00UTC 07 DEC 2013 (09KST 07 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 08 DEC 2013 (09KST 08 DEC 2013)

00UTC 08 DEC 2013 (09KST 08 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E

50∘N

40∘N

30∘N

20∘N

40∘N

30∘N

20∘N



00UTC 09 DEC 2013 (09KST 09 DEC 2013)

00UTC 09 DEC 2013 (09KST 09 DEC 2013)


160∘E150∘E140∘E130∘E120∘E110∘E100∘E090∘E

140∘E130∘E120∘E110∘E



2 CO and CH

4as the latter is





2 CO CH

4 BC and PM

25between prehaze


2 BC and

PM25



25)




minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


minus10 0 5 10 15 20minus5

Temperature (∘C)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Hei

ght (

m)

4 Dec5 Dec6 Dec

7 Dec8 Dec9 Dec











4 BC and PM



25presented


4had not


4 CO BC and PM

25presented




2)







4 BC and PM

25 the mini-





2 and CH




Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in


Strong hazePrehaze

2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

2 4 6 80 12 14 16 18 20 2210

Hour2 4 6 80 12 14 16 18 20 2210

Hour

0

50

100

150

200

250

300

350

400

PM2

5co

ncen

trat

ion

(120583g m

minus3)

0

5

10

15

20

25

BC co

ncen

trat

ion

(120583g m

minus3)

18

19

20

21

22

23

24

25

CH4

conc

entr

atio

n (p

pm)

400

420

440

460

480

500

CO2

conc

entr

atio

n (p

pm)

00

02

04

06

08

10

12

14

16

18

20

22

24

CO co

ncen

trat

ion

(ppm

)


4 BC and PM



4ΔCO

2in haze





2ΔCO + ΔCO





2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in



2 and CH


2 and

ΔCH4ΔCO



2


4and CO

2


2(ppmppm) 00150 00217

ΔCH4ΔCO

2(ppmppm) 00022 00054

119875 lt 00001



2 ΔCH

4ΔCO

2 and


4 Conclusion






25



2 COCH

4 BC and PM



2 CO CH

4



2 CH4and CO

2in


Competing Interests


Acknowledgments


References






































25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in




























25 and black carbon


























2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in














2at Lampedusardquo





















Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in










Volume 2014

Mining


Journal of



Geophysics







Journal of




Advances in











Geology Advances in

Documents

Research Article Characteristics of Atmospheric