Copernicus Atmosphere Monitoring Service...Copernicus Atmosphere Monitoring Service CAMS71_2016SC3 – Annual air quality assessment report for 2016 Page 3 of 47 Annual air quality

ECMWF COPERNICUS REPORT

Copernicus Atmosphere Monitoring Service

Annual air quality assessment report 2016

Issued by: INERIS/ Laurence ROUÏL

Date: 14/02/2019

Ref: CAMS71_2016SC3_D71.2.11_201811_2016AAR_v2

This document has been produced in the context of the Copernicus Atmosphere Monitoring Service (CAMS).

The activities leading to these results have been contracted by the European Centre for Medium-Range Weather Forecasts,

operator of CAMS on behalf of the European Union (Delegation Agreement signed on 11/11/2014). All information in this

document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose.

The user thereof uses the information at its sole risk and liability. For the avoidance of all doubts, the European Commission

and the European Centre for Medium-Range Weather Forecasts has no liability in respect of this document, which is merely

representing the authors view.


CAMS71_2016SC3 – Annual air quality assessment report for 2016 Page 3 of 47

Annual air quality assessment report -2016

INERIS Laurence ROUÏL

Frédérik MELEUX

Date: 14/02/2019

Ref: CAMS71_2016SC3_D71.2.11_201811_2016AAR_v2


Table of Contents

1. Rationale 10

2. Ozone 12

2.1 Annual and seasonal averages 12

2.2 Exposure indicators 16

2.3 Peaks indicators 23

2.4 Conclusions for ozone 24

3. Nitrogen dioxide 26


3.2 Conclusions for nitrogen dioxide 30

4. Particulate Matter (PM10) 31


4.2 Daily exceedances 33

4.3 Conclusions for PM10 36

5. Particulate Matter (PM2.5) 37


5.2 Conclusions for PM2.5 41


Table of figures

Annual average of ozone concentrations in 2016 13

Annual average of ozone concentrations in 2015 (left) and 2014 (right) (Source : CAMS – 2015 and 2014

air quality assessment reports) 13

Seasonal averages of ozone concentrations in 2016: Spring (a), Summer (b), autumn (c), winter(d) 14

Surface air temperature in 2016 relative to its 1981-2010 average (a) May, (b) June, (c) July, (d) August

(source: ECMWF, Copernicus Climate Change Service -C3S temperature re-analyses) 15

AOT40 indicator in 2016 – CAMS re-analysis 17

AOT indicator in 2016 issued from ozone observations reported to the EEA (source: EEA data viewer) 18

SOMO35 indicator in 2016 – CAMS re-analysis 19

SOMO35 indicator in 2016 issued from ozone observations reported to the EEA (source: EEA data viewer)

19

SOMO35 indicator in 2015 (source : CAMS – 2015 air quality assessment report) 20

Number of days when 120 µg/m3 (maximum daily 8-hours average) was exceeded in 2016 - CAMS re-

analysis 21

Number of days when 120 µg/m3 (maximum daily 8-hours average) was exceeded in 2016 -CAMS re-

analysis- zoom over the Pô Valley (left) and the Benelux (right) 21

Number of days when 100 µg/m3 (maximum daily 8-hours average) was exceeded in 2016 -CAMS re-

analysis- zoom over the Pô Valley (left) and the “Black Triangle” (right) 22

Number of hours when the information ozone threshold (180 µg/m3) was exceeded in 2016 -CAMS re-

analysis - 23

Stations where the information ozone threshold (180 µg/m3) has been exceeded in 2016 (in dark

orange) according to observation data reported to the EEA (Source : EEA data viewer) 24

Annual average of NO2 concentrations in 2016 27

Annual average of NO2 concentrations in 2015 (Source : CAMS – 2015 air quality assessment report) 27

Annual average of NO2 concentrations in 2016 - CAMS re-analysis- zoom over the Pô Valley (left) and the

Benelux (right) 28

NO2 annual average in 2016 at the monitoring background stations reported to the EEA (source: EEA

data viewer) 28

Seasonal averages of NO2 concentrations in 2016; Spring (a), Summer (b), autumn (c), winter (d) 29

Surface air temperature in 2016 relative to its 1981-2010 average (a) October, (b) November (source:

ECMWF, Copernicus Climate Change Service -C3S temperature re-analyses) 30

Annual average of PM10 concentrations in 2016- CAMS re-analysis 32

PM10 annual average in 2016 at the monitoring background stations reported to the EEA (source: EEA

data viewer) 32

Seasonal averages of PM10 concentrations in 2016; Spring (a), Summer (b), autumn (c), winter (d) 33

Number of days when the daily limit PM10 value was exceeded in 2016 34

Number of days when PM10 daily average exceeded the daily limit value in 2016 at the monitoring

background stations reported to the EEA (source: EEA data viewer) 35

Number of days when the daily limit PM10 value was exceeded in 2016; zooms over the Pô Valley (left)

and the “Black triangle” (right) 35

Annual average of PM2.5 concentrations in 2016- CAMS re-analysis- 38

PM2.5 annual average in 2016 at the monitoring background stations reported to the EEA (source: EEA

data viewer) 38

Seasonal averages of PM2.5 concentrations in 2016; Spring (a), Summer (b), autumn (c), winter (d) 39

Number of days when daily average exceeded 25 µg/m3 in 2016 -CAMS re-analysis 40

Number of days when daily average exceeded 25 µg/m3 in 2016 -CAMS re-analysis; zooms over Benelux

(left), the “Black triangle” (right) and the Pô valley (bottom) 40

Taylor diagram synthesizing scores for IRA2016 and VRA2016 by station typology for ozone daily

maximum indicator 44

Taylor diagram synthesizing scores for IRA2016 and VRA2016 by station typology for PM10 daily average

45


Taylor diagram synthesizing scores for IRA2016 and VRA2016 by station typology for PM2.5 daily average

45

Number of days when daily average exceeded 35 µg/m3 in 2016 simulated by CAMS Ensemble model:

interim re-analyses (left) and validated re-analyses (right) 46


Executive summary

This report is the CAMS air quality annual assessment report for the year 2016 delivered by the CAMS

regional air quality re-analysis multi-model system implemented. The air quality assessment

European maps presented and discussed in this report, result from an Ensemble model built upon

seven European regional air quality modelling and data assimilation systems. Such approaches

combine raw simulation outputs from chemistry-transport models (CTM) with validated observations

data issued from monitoring in-situ stations from regulatory air quality networks implemented in the

EU Member States to comply with air quality Directives (2008/50/EC).

For main air pollutants - ozone, nitrogen dioxide, and particulate matter (PM10 and PM2.5)- regulatory

and exposure indicators established on yearly and seasonal bases are presented. It is expected this

very comprehensive information on air pollution patterns and levels, can be considered as the “best

estimate” to describe status of air pollution in Europe in 2016. It should be noted that within CAMS

quality assurance processes, systematic evaluation of the modeled and data assimilated results

against a relevant set of dedicated observation data (not used for assimilation in the models) is

performed. It showed very satisfactory performances confirming reliability and quality of the results

presented, and the relevance of the approach to support analysis of air pollution issues in Europe and

support decision making.

It is important to note that CAMS regional air quality re-analyses are relevant for assessing rural and

urban background concentrations and areas where they exceed limit values and quality objectives

set in the Directive on ambient air pollution and cleaner air in Europe (2008/50/EC). However, it is

also agreed that the CAMS air quality regional assessments are not suited for mapping local

exceedances (street canyons, industrial sites). Models resolution (10 km) is too coarse to simulate

correctly such situations. Indicators fields mapped in this report are compared to air pollutants

observations reported to the European Environment Agency (EEA) by the Member States in

compliance with the implementation provision of the air quality Directive 2008/50/EC. The EEA has

developed a data viewer (http://eeadmz1-cws-wp-air.azurewebsites.net/products/data-

viewers/statistical-viewer-public/) which allows to display observed indicators at monitoring stations.

This report includes a number of snapshots of the EEA’s data viewer which show good consistency

between CAMS re-analyses and reported air quality measurements. The review of the status of air

quality in Europe in 2016 has been published in October 2018 by the EEA1.

The year 2016 revealed interesting issues in terms of air pollution and although rather comparable to

the previous years in term of air pollution patterns. Globally temperatures in Europe were high, but

less than in 2015 which was exceptional on this point of view. This impacted the air pollution patterns

1 Air Quality in Europe- 2018 report, EEA report N° 12/2018; https://www.eea.europa.eu/publications/air-

quality-in-europe-2018


and in particular ozone concentrations (which are largely driven by sunny and warm temperatures)

and particulate matter episodes.

Main conclusions and lessons learnt from this analysis are summarized below.

For ozone:

• The situation improved compared to previous years. But decrease in ozone concentration is

mainly due to the favorable meteorological situations that occurred over the year, even if one

can expect positive impact of precursors emission reduction strategies implemented in the

European Union for several years. Ozone is very sensitive to inter-annual meteorological

variability and yearly results may only reflect the influence of this factor.

• However, ozone annual average in Europe ranged from 35 to 90 µg/m3 and they are still high

in the Mediterranean countries: Portugal, Spain, Italy, Slovenia, Croatia, Montenegro, Albania,

Greece, Turkey.

• Spring average concentrations were remarkably high everywhere in Europe (also in

Scandinavia and Northern Europe) which confirms the trend to “early ozone episodes” already

observed in the previous years.

• Ecosystems and human health exposure indicators still show areas where regulatory target

values were exceeded. The most exposed regions were Southern countries. However, when

the threshold recommended by WHO for the 8-hours daily maximum average is considered,

the area exposed to its exceedance included a large part of Europe and not only

Mediterranean countries. Only Iceland, the UK, Scandinavia and far-Eastern countries were

spared.

• The number of hourly peaks exceeding the information regulatory threshold (180 µg/m3) was

not very high and lower than in 2015. Such exceedances occurred mainly in the Pô Valley.

• Considering the 2016 situation and the previous years, we cannot conclude about a decreasing

trend, regarding ozone background concentrations in Europe despite precursor emissions

strategies implemented in European Union over the past years. The situation seemed to

improve in 2016 but it can be the consequence of favorable meteorological conditions.

Sensitivity of ozone formation processes to meteorological variability and increasing

temperatures and influence of hemispheric transport of ozone may counter-balance the

efficiency of regional emissions control strategies.

For nitrogen dioxide:

• Background nitrogen dioxide concentrations exceeded in 2016 the annual limit value in

several places generally characterized by high NOx emissions. The Pô Valley is one of the most

exposed area, because of the convergence of high emission levels and non-dispersive

meteorological conditions in the valley. Paris area and Benelux were also impacted by

exceedances of the limit value in 2016.

• NO2 concentrations were the highest in the biggest cities, near main roads and in sea areas

because of shipping emissions.


• Air concentrations distribution of NO2 in Europe and their seasonal variability remain

relatively stable compared to the past years. Influence of meteorology can lead to slight

changes in the distribution patterns, especially in winter and fall, when because of colder and

more stable meteorological conditions, the extension of areas with high concentrations can

vary from a season to another. Thus, in 2016, because of colder temperatures, NO2

concentrations where higher in fall than in winter..

For particulate matter (PM10 and PM2.5):

• PM10 annual average of background concentrations ranged in 2016 from very low level (3

µg/m3) in a large part of Northern Europe to high values (higher than 35 µg/m3 in average) in

the Pô Valley and Eastern Europe (Poland, Serbia, republic of Northern Macedonia in

particular). The annual limit value was exceeded in those countries. The conjunction of high

emissions, especially in the residential heating and wood burning sector together with cold

and stable meteorological conditions can partly explain increasing PM concentrations in those

regions where concentrations were generally higher than in 2015.

• Western Europe (France, Benelux, Germany) usually exposed to high PM concentrations was

rather spared in 2016, certainly because of the absence of meteorological conditions likely to

favor PM formation in spring period when agriculture ammonia emissions are usually high,

making ammonia available in the atmosphere to contribute to ammonium nitrate particles

formation.

• However, geographical distribution of PM10 concentrations in Europe in 2016 was very

consistent with what was observed the previous years. Eastern part of Europe and Pô valley

remained the most exposed areas.

• Comparing the re-analyses to the observations reported to the EEA by the countries, it seems

that high concentrations measured in the south-East of Europe (Turkey, Bulgaria) were largely

underestimated by the modelling results. The reason why (uncertainties in the emission

inventories, in the chemistry or lack of observations to be assimilated) should be furthermore

investigated.

• Exposure to fine particulate matter in Europe (PM.2.5) remains a sensitive issue in Europe. If

the current limit value for annual average set in the Air Quality Directive (25 µg/m3) was

exceeded in 2016 only in few areas in Northern Italy, Poland, Serbia and Turkey, exposure to

more stringent thresholds (20 µg/m3 as the indicative limit value proposed in the air quality

Directive to be implemented in 2020 or 10 µg/m3 according to WHO recommendations) is

worrying. Considering such threshold values, a large part of Europe was concerned by

exceedances in 2016.

• This conclusion is the same when considering the number of days when the daily mean

exceeds the 25 µg/m3 threshold (which is just indicative and not regulatory). A large part of

Europe (Pô Valley, Central and South-Eastern Europe, and Benelux) recorded more than 25

exceedance days.

• Pô Valley, Poland, South-Central Europe, were the most sensitive areas in 2016, with highest

concentrations in autumn and winter. The influence of residential heating is one of the main

drivers explaining this situation, together with cold and stable meteorological conditions

which avoided dispersion of the pollutants, again in 2016, but not only since quite high

concentrations are recorded in spring and summer as well.


1. Rationale

This report is the Copernicus air quality assessment report for the year 2016 for Europe.

It presents, and comments best estimates and maps of air quality indicators elaborated by air quality

models (regional chemistry-transport models) and assimilating validated or “official” air quality

observations from in-situ regulatory observation networks implemented in Europe. Such simulations

are called re-analyses. Within the CAMS framework, air quality regional re-analyses are built upon a

set of seven air quality models implemented with data assimilation systems to improve air pollution

patterns and levels. Their results are combined as the median of the individual models results in a

unique Ensemble model that is more robust and more accurate, in general, than the individual ones.

Regional re-analyses (or assessments) of air pollutant concentrations and metrics which describe the

situation over the past years are considered as the best estimates that can be achieved to describe

background air pollution in Europe

Thus, so-called CAMS European air quality assessment reports describe, with a yearly frequency, the

state and the evolution of background concentrations of air pollutants in European countries. Special

care is given to pollutants characterized by the influence of long range transport, correctly caught by

European scale modelling systems: ozone, nitrogen dioxide, particulate matter (PM10 and PM2.5).

The Copernicus annual air quality assessment reports aspire to become useful tools for supporting

European policy and decision makers in charge of air quality monitoring and management. For the

targeted pollutants, regulatory and exposure indicators built up from airborne hourly concentrations

are proposed. They are interpreted with respect to the limit, objective and target values set in the

Directive on Ambient Air quality and Cleaner Air for Europe (the AQ 2008/50/EC of 21 May 2008).

Therefore, this report can provide the EU Member States with valuable information when they have

to report to the European Commission air pollution levels and situations when those threshold values

are exceeded and to inform their citizens about which levels they are exposed to.

According to the 2008 Directive, situations (or episodes) when nitrogen dioxide and particulate

matter concentrations exceed regulatory limit values (or target values for ozone) must be carefully

analyzed, described (geographical extension, duration, intensity, population exposed...) and action

plans to limit their impact and to avoid their future development must be proposed. Member states

usually base their investigations on observations available from national air quality monitoring

networks implemented to comply with the Directives requirements, and national expertise.

This report provides complementary information with an accurate and reliable description of air

pollution patterns that developed throughout the European region. Maps resulting from modelling

and observation data assimilation processes are synthesized and interpreted for policy users as well

as general public. For each pollutant considered, annual and seasonal indicators (averages, exposure

indicators, number of exceedances of threshold values) are proposed and commented. It should be

noted that the spatial resolution of the proposed maps does not allow a fine description of very local

patterns (inside the city) or hot spots (near busy roads or industrial sites). Only background

concentrations in or outside cities are proposed. They are representative of the influence of both

local and regional sources.


Finally, annex I gives a very short description of the modelling set-up implemented by the regional

Copernicus Atmosphere Monitoring Services to elaborated validated air quality re-analyses presented

in this report.

Technical annex II presents a preliminary analysis of performance indicators for interim and validated

re-analyses related to the year 2016, demonstrating the added-value of use of validated observation

datasets to be assimilated in the models.


2. Ozone

2.1 Annual and seasonal averages

Figure 1 and Figure 3 present 2016 ozone annual and seasonal averages respectively. These metrics

are not directly used for air quality policy implementation in Europe but help in understanding:

1) the North-South gradient of concentrations

2) the seasonal variability

In 2016, ozone annual average in Europe (Figure 1) ranged from 30 to 90 µg/m3. Highest

concentrations were recorded in the Mediterranean basin which is perfectly drawn, while in other

countries concentrations rather ranged from 40 to 60 µg/m3, and the overall concentration

distribution is quite similar to in 2015 (Figure 2). Ozone annual averages were remarkably high in

some parts of Scandinavia (higher than 60 µg/m3), as in the previous years. Locally ozone annual

average exceeded 70 µg/m3 in Switzerland, Austria, Czech Republic and in Iceland.

The seasonal variability of ozone concentrations is displayed on maps of Figure 3. The most

remarkable facts highlighted are very high spring ozone concentrations everywhere in Europe on one

side, and quite high concentrations in winter (especially in Scandinavia and Western Europe) on the

other side. Spring ozone concentrations exceeded 60-70 µg/m3 in areas where they were even higher

than the summer average (North Scandinavia).

The Mediterranean area was the most impacted by ozone in summer with average concentrations

exceeding 90-100 µg/m3 as an average in spring and summer.

Figure 4 series are issued from the C3S Copernicus Climate services and show the global surface

temperature anomaly in 2016 compared to the 1980-2010 average for May, June, July, August and

December 2016. When colors tend to red, surface temperature is higher than the average recorded

over the last 3 decades. Exceptional high temperatures were recorded in May and December in

Scandinavia and North-Eastern Europe, with anomalies exceeding 5°C. It can explain the high ozone

concentrations recorded in those regions in spring and Winter (Figure 3 a and d).

In July and August 2016, the anomaly is not so pronounced throughout the European domain which

can explain that ozone concentrations, driven by sunny and warm meteorological conditions, did not

increase so drastically in summer 2016 compared to previous years. In particular, August was rather

cool in a large part of Eastern Europe.


Annual average of ozone concentrations in 2016

Annual average of ozone concentrations in 2015 (left) and 2014 (right)

(Source : CAMS – 2015 and 2014 air quality assessment reports)


Seasonal averages of ozone concentrations in 2016:

Spring (a), Summer (b), autumn (c), winter(d)

(a) (b)

(c) (d)


Surface air temperature in 2016 relative to its 1981-2010 average

(a) May, (b) June, (c) July, (d) August

(source: ECMWF, Copernicus Climate Change Service -C3S temperature re-analyses)

(a)

(b)

(c)

(d)


(e)

2.2 Exposure indicators

Three regulatory exposure indicators are presented in this section:

• AOT 40 (Accumulated dose over a threshold of 40 ppb) used to assess ozone impact on

vegetation.

• Number of days when maximum daily eight hours mean exceeds 120 µg/m3 used as an

indicator for protection of human health

• SOMO35 (Sum of ozone mean over a threshold of 35 ppb) used to assess long term human

exposure to ozone concentrations

The two first indicators are defined in the Air Quality Directive 2008/50/EC, while the third one is

recommended by the World Health Organization (WHO) for quantification of health impacts of ozone

and was used to set target effect objectives for the negotiations of the revision of the Gothenburg

protocol of the UNECE Convention on Long Range Transboundary Air pollution and of the EU Directive

on National Emission Ceilings (2016/2284/EU). Regarding daily maximum 8-hours average exposure,

WHO recommends rather the threshold of 100 µg/m3 not to be exceeded (instead of 120 µg/m3 in

the air quality directive)

AOT 40 (Accumulated dose over a threshold of 40 ppb) requires for its calculation hourly ozone data.

It is the sum of the differences between the hourly ozone concentration (in ppb) and 40 ppb, for each

hour when the concentration exceeds 40 ppb, accumulated during daylight hours (8:00-20:00 UTC).

AOT40 has a dimension of (µg/m3)·hours. In the 2008 Air Quality Directive, the target value for the

protection of vegetation is defined as the AOT40 calculated from May to July and is set at 18.000

(µg/m3)·hours, with a long term objective of 6.000 (µg/m3)·hours.

Figure 5 presents AOT4O indicator calculated from the CAMS re-analyses for the period from May to

July 2016, which significantly improved compared to the year 2015 (see CAMS 2015 annual

assessment report on air quality in Europe). However, considering longer term analyses 2 this

improvement should rather be attributed to favorable meteorological conditions that occurred in

2016. The impact of emission reductions strategies implemented for several years cannot be

2 Air Quality in Europe- 2018 report, EEA report N° 12/2018; https://www.eea.europa.eu/publications/air-

quality-in-europe-2018


monitored in a year per year analysis. Indeed, over the 20 past years no clear decreasing trend in

ozone concentrations was observed in Europe. All Mediterranean countries are concerned by

exceedances of the current target value for protection of the vegetation: Spain, South of France, Italy,

Slovenia, Croatia, Greece, Turkey.

As usually, more worrying is compliance with the long term objective of 6000 (µg/m3).hours. This

objective is exceeded in a large part of Europe, except in Nordic countries, in the United Kingdom,

along the Atlantic coast and in Romania and far-East of Europe.

Figure 6 displays the same AOT40 indicator monitor by the ozone stations that report measurements

to the EEA. It is issued, as several snapshots proposed in this report from the EEA data viewer available

at http://eeadmz1-cws-wp-air.azurewebsites.net/products/data-viewers/statistical-viewer-public/.

Same colour scales are used to facilitate comparison and we show that modelling (Figure 5) and

measurement (Figure 6) pictures are very similar with a pronounced North/South gradient and low

impacts in the UK and Eastern Europe.

AOT40 indicator in 2016 – CAMS re-analysis


AOT indicator in 2016 issued from ozone observations reported to the EEA

(source: EEA data viewer)

SOMO35 is the sum of the differences between maximum daily 8-hour running mean concentrations

greater than 35 ppb. SOMO35’s dimension is (µg/m3)·days. This indicator is calculated for the whole

year to be representative of long term exposure of human health to ozone background

concentrations. There is currently no target value or long term objective for this indicator. Its annual

variation is monitored to assess its improvement or degradation with implementation of emissions

control strategies.

Figure 7 represents the SOMO35 calculated for the year 2016 thanks to the CAMS re-analyses, and

Figure 8 is a snapshot from the EEA data viewer which presents the SOMO35 indicator calculated at

each station reported by the Member states. Both are very similar and highlight clearly a South/North

gradient showing Mediterranean countries are much more exposed than other countries. Figure 9 is

issued from the 2015 annual assessment report and highlights the facts that ozone impacts patterns

are quite similar from a year to another. Almost all countries in Western, Southern and Central Europe

had SOMO35 values still higher than 4 000 (µg/m3).days in 2016. Only Atlantic and North Sea sides

were spared with the United Kingdom, Scandinavia and the far-East part of Europe, with values lower

than 2 000 (µg/m3).days.


SOMO35 indicator in 2016 – CAMS re-analysis

SOMO35 indicator in 2016 issued from ozone observations reported to the EEA



SOMO35 indicator in 2015

(source : CAMS – 2015 air quality assessment report)

In the Air Quality Directive 2008/50/EC, health protection target value refers to the number of days

when the 8-hours average daily maximum of ozone exceeds 120 µg/m3. This number of days should

not be higher than 25 per year as an average over 3 years.

This indicator is displayed for the year 2016 on Figure 10, and zooms over two of the most concerned

regions (Pô Valley and Benelux) are proposed on Figure 11. The areas where the target value are

found in a quite limited number of Mediterranean countries: local exceedances in Portugal, Spain,

France, Italy, Greece and Turkey. At this stage, we can only attribute these encouraging results to

favorable metrological conditions, since the situation was worse in 2015 (example Figure 9).

However, it is interesting to consider the same indicator (8-hours average daily maximum of ozone)

calculated with the threshold value recommended in the World Health Organization (WHO)

guidelines: 100 µg/m3. The annual map and zooms are proposed respectively on Figure 10 and Figure

11. They show different conclusions than those drawn with the regulatory threshold, since almost the

whole of Europe recorded more than 25 days when the WHO threshold is exceeded. Only

Scandinavia, Iceland, the United Kingdom and the Far-East of Europe had less than 10. It should be

noted that the geographical distribution of areas where health impacts of ozone are likely to be the

highest changes as well with this new threshold. Pô valley is still the most exposed area in Europe

with more than 50 days of exceedance recorded everywhere (Figure 12- left), but other areas give a

worrying picture, for instance the “Black Triangle” region covering Poland, Czech Republic and East

of Germany (Figure 12- right). Czech Republic and a large part of Poland recorded more than 50

exceedance days as well.


Number of days when 120 µg/m3 (maximum daily 8-hours average) was exceeded in

2016 - CAMS re-analysis


2016 -CAMS re-analysis- zoom over the Pô Valley (left) and the Benelux (right)


Number of days when 100 µg/m3 (maximum daily 8-hours average) was exceeded in 2016 - CAMS

re-analysis-


2016 -CAMS re-analysis- zoom over the Pô Valley (left) and the “Black Triangle” (right)


2.3 Peaks indicators

The European legislation sets information and alert hourly thresholds values for ozone concentrations

that should not be exceeded. Those are not limit values, however they are used to describe situations

when ozone concentrations become very high and justify implementation of short term action plans

or emergency measures to quickly decrease or stabilize ozone levels, and to control harmful impacts

of ozone on human health. Threshold values are respectively 180 µg/m3 and 240 µg/m3 (hourly

averages) for information and alert levels.

Figure 13 shows the number of hours when the information threshold was exceeded in 2016, and as

expected it is very low. Only Italy and the Pô Valley showed exceedances of the information threshold,

and no exceedance of the alert threshold was detected. The number estimated is confirmed by EEA’s

observation map (Figure 14) which presents, among all available stations (in light-orange) those that

recorded exceedances of the information hourly threshold (plotted in dark-orange). The map is very

consistent with CAMS result with a spot in Northern Italy and 1 or 2 stations in Turkey that were not

targeted by the re-analyses. However, both approaches give quite similar results.

Number of hours when the information ozone threshold (180 µg/m3)

was exceeded in 2016 -CAMS re-analysis -


Stations where the information ozone threshold (180 µg/m3)

has been exceeded in 2016 (in dark orange) according to observation data reported to the

EEA (Source : EEA data viewer)

2.4 Conclusions for ozone

• The situation seems to have improved compared to previous years. But decrease in ozone

concentration is mainly due to the favorable meteorological situations that occurred over the

year 2016, even if one can expect positive impact of precursors emission reduction strategies

implemented in the European Union for several years. Ozone is very sensitive to inter-annual

meteorological variability and yearly results may only reflect the influence of this factor.

• However, ozone annual averages in Europe ranged from 35 to 90 µg/m3 and they are still high

in the Mediterranean countries: Portugal, Spain, Italy, Slovenia, Croatia, Montenegro, Albania,

Greece, Turkey.

• Spring average concentrations were remarkably high everywhere in Europe (also in

Scandinavia and Northern Europe) which confirms the trend to “early ozone episodes” already

observed in the previous years.

• Ecosystems and human health exposure indicators still show areas where regulatory target

values were exceeded. The most exposed regions were Southern countries.

• However, when the threshold recommended by WHO for the 8-hours daily maximum average

is considered, the area exposed to exceedances becomes much larger and includes a large

part of Europe and not only Mediterranean countries. Only Iceland, the UK, Scandinavia and

far-Eastern countries are spared.


• The number of hourly peaks exceeding the information regulatory threshold (180 µg/m3) was

quite low in 2016. Such exceedances occurred mainly in the Pô Valley.

• Considering the 2016 situation and the previous years, we cannot conclude about a decreasing

trend, regarding ozone background concentrations in Europe despite precursor emissions

strategies implemented in European Union over the past years. The situation seemed to

improve in 2016 but it can be the consequence of favorable meteorological conditions.

Sensitivity of ozone formation processes to meteorological variability and increasing

temperatures and influence of hemispheric transport of ozone may counter-balance the

efficiency of regional emissions control strategies.


3. Nitrogen dioxide Warning note: It should be noted that the CAMS re-analyses mapping system is not fitted to deal with

local hot spot situations that can develop near busy or on industrial sites. Actually, the models

resolution is about 10*10 km, and is not sufficient to catch actual NO2 concentrations at traffic and

industrial sites. This is also the reason why no map of indicators related to the number of situations

when the limit hourly value of the Air Quality Directive is exceeded is proposed in this report. In most

of the cases such situations occur at traffic sites, near busy roads, and cannot be described by the

European-wide re-analysis system implemented in CAMS. However, the maps presented below give a

good estimate of background concentrations levels and patterns.


Annual and seasonal averages of NO2 concentrations are presented on Figure 15 and Figure 19b. The

2008 Air Quality Directive sets a limit value for the annual average of NO2 concentrations which

must not exceed 40 µg/m3.

Figure 15 shows that background concentrations exceeded the annual limit value in Milan, Ankara

and in Moscow areas, as in 2015 (Figure 16). Cities footprints appear very clearly as main roads and

maritime routes. Highest concentrations are found in the Benelux, South-East of the United Kingdom,

Western Germany, Poland, Paris and Ile de France, Madrid, Istanbul and Ankara areas, and in the Pô

Valley. In those places, annual averages generally exceeded 30 µg/m3 according to the CAMS re-

analyses. The concentrations distribution is driven by the location of main sources of nitrogen oxides

(NOx), NO2 behaving as a “local pollutant” with very shorts life time in the atmosphere.

Figure 17 proposes zooms of NO2 annual averages over the Pô valley and the Benelux regions. A

simplified color scale helps in highlighting the places where the annual limit value of 40 µg/m3 was

exceeded in the concerned countries. They correspond to urban areas. This diagnostic is confirmed

by the snapshot fromestimate the EEA data viewer web site which presents NO2 annual average

concentrations in 2016 monitored at background stations (industrial and traffic stations are excluded

since they are out of scope of CAMS products). It illustrates good consistency with CAMS re-analyses

regarding the spatial distribution of NO2 concentrations. However, the highest levels are

underestimated in large urban areas: Madrid, Barcelona, London, Belgrade, Izmir, Istanbul and more

generally a large part of Turkey monitored NO2 annual averages higher than the limit values which

are not picked at this level by the analyzed maps3. Lack of observations to be assimilated in the models

and uncertainties in the emission inventories can explain this situation.

3 According to EEA’s data, the hourly limit value (200 µg/m3) had been exceeded only in Belgrade and in

Turkish cities


Annual average of NO2 concentrations in 2016

Annual average of NO2 concentrations in 2015

(Source : CAMS – 2015 air quality assessment report)


Annual average of NO2 concentrations in 2016 - CAMS re-analysis- zoom over the Pô

Valley (left) and the Benelux (right)

NO2 annual average in 2016 at the monitoring background stations reported to the

EEA (source: EEA data viewer)

Maps on Figure 19 propose geographical distribution of seasonal NO2 concentrations. They are

significantly lower in spring and summer than in fall and winter. Two main reasons explain this

difference: higher NOx emissions from residential heating that usually go along with temperatures

decrease on one side and stable and cold meteorological conditions leading to thermal inversions


that stick ground level emissions near the surface on the other side. However, a remarkable point for

the year 2016 was that average concentrations in fall are as high as in winter (and even locally higher),

especially in the large city centers. A quick look at the temperatures anomalies maps in October and

November 2016 assessed by the C3S Copernicus climate services allows a first explanation with

temperatures lower by almost 4 °C than the last 3 decades average during these months. Cold and

stable meteorological conditions (with the formation of persistent inversion layers) are the main

reasons to explain NO2 raise of concentrations since this pollutant is mainly emitted by ground level

combustion processes (road traffic, residential heating).

Biggest cities (Paris, Madrid, Barcelona, Brussels, Berlin, London, Ankara and Moscow), the Benelux

and the Pô valley are clearly impacted by such effects with seasonal concentration averages above

40 µg/m3 in fall and winter times.

Seasonal averages of NO2 concentrations in 2016;

Spring (a), Summer (b), autumn (c), winter (d)

(a) (b)

(c) (d)


Surface air temperature in 2016 relative to its 1981-2010 average

(a) October, (b) November

(source: ECMWF, Copernicus Climate Change Service -C3S temperature re-analyses)

(a)

(b)

3.2 Conclusions for nitrogen dioxide

• Background nitrogen dioxide concentrations exceeded in 2016 the annual limit value in

several places generally characterized by high NOx emissions. The Pô Valley is one of the most

exposed area, because of the convergence of high emission levels and non-dispersive

meteorological conditions in the valley. Paris area and Benelux were also impacted by

exceedances of the limit value in 2016.

• NO2 concentrations were the highest in the biggest cities, near main roads and in sea areas

because of shipping emissions.

• Air concentrations distribution of NO2 in Europe and their seasonal variability remain

relatively stable compared to the past years. Influence of meteorology can lead to slight

changes in the distribution patterns, especially in winter and fall, when because of colder and

more stable meteorological conditions, the extension of areas with high concentrations can

vary from a season to another. Thus, in 2016, because of colder temperatures, NO2

concentrations where higher in fall than in winter.

.


4. Particulate Matter (PM10)


Annual and seasonal averages of PM10 concentrations in 2016 are presented in Figure 21 and Figure

23 respectively. The air quality Directive 2008/50/EC sets a limit value for PM10 annual average to

40 µg/m3.

In 2016, PM10 background annual average ranged from 5 µg/m3 in Northern Europe (Iceland,

Scandinavia), to more than 30 µg/m3 locally (Figure 21), and especially in the Eastern part of Europe

(in Poland, Serbia, Republic of Northern Macedonia) and in the Pô Valley, and this pattern is

remarkably similar to the distribution in 2015 re-analyses. This diagnostic is confirmed by the

comparison of the 2016 CAMS re-analyzed map with background observation data reported to the

EEA in accordance to the air quality Directive (Figure 22). However, it should be noted a strong

underestimation of CAMS re-analysis PM values in Turkey (compared to the observations) which can

be explained by a lack of observation data assimilated in the model for this country. This

underestimation can be noted for other the countries in the South-East of Europe: Albania,

Montenegro, Bosnia and Herzegovina, Republic of Northern Macedonia. Uncertainties in emissions

inventories and lack of observation data to be assimilated can explain this shortcoming.

Seasonal analyses (Figure 23) show that PM concentrations were generally quite low (no larger than

30 µg/m3) everywhere in summer and spring 2016, except in the South of the domain. Mineral

Saharan dust contributed to high levels of PM in North Africa and impacted Mediterranean countries.

Concentrations in fall and winter were significantly higher and influence the annual average. Also,

autumn and winter present remarkably similar patterns in PM10 distribution, which proves the

influence of local sources, and residential heating in particular (October-November were particularly

cold – see Figure 20). Combination of increasing emissions and stable and cold meteorological

conditions that generally develop at the same time and stuck air pollutants near the ground can

explain increasing ambient concentrations. During these seasons CAMS re-analyses detect local

exceedances of the annual limit value in the Pô valley, Poland, Serbia, Republic of Northern

Macedonia.

It is interesting to note that 2016 did not really experience high PM concentrations in spring or at the

end of winter as observed in 2014 and 2015. In this period, in Western Europe, daily temperature

gradients may be very important (cold nights and mild days) which favors thermal inversions, and

ammonia emissions from agriculture activities (manure and fertilizers spreading) may be very

important due to volatilization processes. Combined with NOx emitted by road traffic and combustion

activities, ammonia can form ammonium nitrate which contributes to PM concentrations increase.

Such spring episodes did not occur in 2016.


Annual average of PM10 concentrations in 2016- CAMS re-analysis

PM10 annual average in 2016 at the monitoring background stations reported to the



Seasonal averages of PM10 concentrations in 2016; Spring (a), Summer (b), autumn (c), winter (d)

(a)

(b)

(c)

(d)

4.2 Daily exceedances

PM10 episodes are characterized by exceedances, over several days, of the daily limit value set in the

Air Quality Directive. According to the EU legislation, the threshold of 50 µg/m3 (daily average)

should not be exceeded more than 35 times a year.

Figure 24 shows annual number of days when PM10 background concentrations exceeded the 50

µg/m3 daily limit value. Because of the resolution of the models, maps are not representative of local

exceedances that can typically occur at traffic stations, but relate to the background level of air

pollution most citizens are exposed to. Therefore, CAMS re-analyses can be compared to the number

of exceedances at background monitoring stations reported to the EEA and displayed by the EEA’s

data viewer (Figure 25).

The countries where the number of exceedances of the daily limit value is the highest (more than 35

days) are Italy, Poland, Serbia, and Republic of Northern Macedonia according to CAMS re-analyses.


But considering observation data reported, exceedances occurred in Czech Republic, Slovakia,

Hungary, Croatia, Bulgaria, Bosnia and Herzegovina, Turkey and more locally in Spain as well.

Moreover, the area were exceedances were measured in Italy and Poland is larger than the one

estimated by the re-analysis Figure 26. This underestimation must be investigated regarding

availability of observation data for assimilation in the re-analysis process or uncertainties in emission

inventories.

Aside, number of exceedances ranged between 5 and 15 in a large part of Western Europe (Benelux,

North of France, Germany) and in a large part of Czech Republic. These numbers are consistent with

observations and significantly lower than what was recorded in 2015 (between 15 and 35).

. Number of days when the daily limit PM10 value was exceeded in 2016


Number of days when PM10 daily average exceeded the daily limit value in 2016 at

the monitoring background stations reported to the EEA


Number of days when the daily limit PM10 value was exceeded in 2016; zooms over

the Pô Valley (left) and the “Black triangle” (right)


4.3 Conclusions for PM10

The main points that can summarize the PM10 diagnostic in 2016 are the following:

• PM10 annual average of background concentrations ranged in 2016 from very low level (3

µg/m3) in a large part of Northern Europe to high values (higher than 35 µg/m3 in average) in

the Pô Valley and Eastern Europe (Poland, Serbia, republic of Northern Macedonia in

particular). The annual limit value was exceeded in those countries. The conjunction of high

emissions, especially in the residential heating and wood burning sector together with cold

and stable meteorological conditions can partly explain increasing PM concentrations in those

regions where concentrations were generally higher than in 2015.

• Western Europe (France, Benelux, Germany) usually exposed to high PM concentrations was

rather spared in 2016, certainly because of the absence of meteorological conditions likely to

favor PM formation in spring period when agriculture ammonia emissions are usually high,

making ammonia available in the atmosphere to contribute to ammonium nitrate particles

formation.

• However, geographical distribution of PM10 concentrations in Europe in 2016 was very

consistent with what was observed the previous years. Eastern part of Europe and Pô valley

remained the most exposed areas.

• Comparing the re-analyses to the observations reported to the EEA by the countries, it seems

that high concentrations measured in the south-East of Europe (Turkey, Bulgaria, Croatia,

Bosnia and Herzegovina) were largely underestimated by the modelling results. The reason

why (uncertainties in the emission inventories, in the chemistry or lack of observations to be

assimilated) should be furthermore investigated.


5. Particulate Matter (PM2.5)


Annual and seasonal averages of PM2.5 concentrations in 2016 are presented in Figure 27 and Figure

29. The 2008 Air Quality Directive sets an annual limit value of 25 µg/m3 that may be reinforced to

20 µg/m3 according to new knowledge and evidences about health impacts and feasibility of

mitigation measures.

As for PM10, only background concentration levels4 are considered. The current limit value for PM2.5

annual mean was exceeded in Northern Italy, Poland, Serbia, Bosnia and Herzegovina, Republic of

Northern Macedonia, Turkey and Ukraine. Exceedances were generally local (see Turkey, Ukraine),

but quite high concentrations (higher than 20 µg/m3) developed over areas larger than the cities in

the most exposed countries. Therefore, the diagnostic would worsen if the more stringent 2020

target value would apply. PM2.5 concentrations were generally higher in 2016 than in 2015 although

geographical patterns are quite similar.

Diagnostic is confirmed by the observations reported to the EEA in compliance with the Air Quality

Directive and presented on the EEA’s data viewer (Erreur ! Source du renvoi introuvable.).

Consistency between observations and CAMS re-analyses is remarkably good for PM2.5, and better

than for PM10.

The situation can even be more critical if the guideline value recommended by the WHO for

controlling human health exposure to fine particulate matter is considered. This value is 10 µg/m3

(annual average). Except in the Northern part of Europe and in few regions in Portugal, Spain, South-

West of France, the UK, and in the mountainous parts of Switzerland, and Austria, this value was likely

to be exceeded everywhere.

Seasonal analysis (Figure 29) shows that the situation was more critical in autumn and winter than in

spring and summer, like for PM10 and NO2, and for the same reasons: cold and stable meteorological

conditions and emissions from the residential heating sector. Italy, Croatia, Poland, Serbia, Bosnia

and Herzegovina, Republic of Northern Macedonia and Romania were the most concerned countries,

especially by winter episodes. However, those maps also show that the WHO guideline value is

exceeded almost everywhere whatever the season, and demonstrate the critical potential harmful

impact of exposure to fine particulate matter in Europe.

4 Local exceedances that can occur near traffic sites cannot be represented on this map because of model

resolution.


Annual average of PM2.5 concentrations in 2016- CAMS re-analysis-

PM2.5 annual average in 2016 at the monitoring background stations reported to the



Seasonal averages of PM2.5 concentrations in 2016; Spring (a), Summer (b), autumn (c), winter (d)

(a)

(b)

(c) (d)

Even if this is not a regulatory indicator, the number of days when daily average exceeded 25 µg/m3

in 2016 gives another instructive overview of fine particulate pollution status in Europe (Figure 30).

In a large part of Europe this indicator exceeded 25 days in 2016. Logically, the countries where the

annual limit value was exceeded recorded highest number of days when the PM2.5 daily mean exceeds

25 µg/m3, but not only. Actually PM2.5 remains an issue in numerous European countries: France,

Belgium, Italy, Croatia, Poland, Czech Republic, Slovakia, Serbia, Bosnia and Herzegovina, Hungary,

Republic of Northern Macedonia and Romania. The map also demonstrates the problem is no longer

local since areas where a high number of days exceeding 25 µg/m3 (daily mean) is recorded are quite

large (Figure 31).


Number of days when daily average exceeded 25 µg/m3 in 2016 -CAMS re-analysis

Number of days when daily average exceeded 25 µg/m3 in 2016 -CAMS re-analysis;

zooms over Benelux (left), the “Black triangle” (right) and the Pô valley (bottom)


5.2 Conclusions for PM2.5

• Exposure to fine particulate matter in Europe (PM.2.5) remains a sensitive issue in Europe. If

the current limit value for annual average set in the Air Quality Directive (25 µg/m3) was

exceeded in 2016 only in few areas in Northern Italy, Poland, Serbia and Turkey, exposure to

more stringent thresholds (20 µg/m3 as the indicative limit value proposed in the air quality

Directive to be implemented in 2020 or 10 µg/m3 according to WHO recommendations) is

worrying. Considering such threshold values, a large part of Europe was concerned by

exceedances in 2016.

• This conclusion is the same when considering the number of days when the daily mean

exceeds the 25 µg/m3 threshold (which is just indicative and not regulatory). A large part of

Europe (Pô Valley, Central and South-Eastern Europe, and Benelux) recorded more than 25

exceedance days.

• Pô Valley, Poland, South-Central Europe, were the most sensitive areas in 2016, with highest

concentrations in autumn and winter. The influence of residential heating is one of the main

drivers explaining this situation, together with cold and stable meteorological conditions

which avoided dispersion of the pollutants, again in 2016, but not only since quite high

concentrations are recorded in spring and summer as well.


Technical annex I

The Copernicus Atmosphere Service component dedicated to regional air quality delivers evaluations

and forecasts of air quality in Europe. Evaluations are based on available observation data-sets (in-

situ and satellite observations) that are used to correct model results with data assimilation

techniques. The combined product is named “analyses” if delivered in a routine daily way using

available data whatever their validation status, or “re-analyses” if delivered within a longer period

which allows verification and validation of the observations.

The service CAMS-50 aims at developing and running operational air quality forecasting platforms

coupled with data assimilation systems to produce on a daily basis up to 4 days forecasts of air

pollutant concentrations (ozone, nitrogen dioxide, PM10 and PM2.5), analyses for the previous day and

re-analyses for the two previous years. Seven models are run in that perspective and their results

(daily concentrations of the targeted pollutants) combined in a composite median model called the

“Ensemble”. The present report is based on Ensemble results that are considered as the best estimate

of air pollutants background concentrations in Europe over the targeted year (2015). The chemistry-

transport models were run with a spatial resolution of about 10 km throughout Europe, and with

similar input datasets. Emissions were issued from the MACC/TNO emission inventory elaborated

within the MACC-suite projects. The 2011 version was available and used. Meteorological inputs were

provided by ECMWF, as chemical boundary conditions from global scale Copernicus atmosphere

services. Fire emissions were taken into account and were available from the Global Fire Assimilation

System (GFAS) developed as a new CAMS service.

The models involved in the European air quality re-analyses production are the following:

Model Origin

CHIMERE INERIS (France)

EMEP Met.No (Norway)

EURAD University of Köln (Germany)

LOTOS-EUROS TNO and KNMI (the

Netherlands)

MATCH SMHI (Sweden)

MOCAGE Meteo France (France)

SILAM FMI (Finland)

Finally, it is essential to note that although the model resolution used (10km*10km) is quite high and

challenging to perform simulations at the European scale, it does not allow to simulate and catch very

local air pollution patterns. Hot spots near emissions sources (busy roads, industrial sites, working

urban areas) cannot be taken into account in this analysis. The figures proposed relate to background

concentrations, whatever the pollutant. Nevertheless, this is a relevant information for national and

local authorities that have to look for control measures impacting most of their territory and

population living in. Hot spots management requires other tools and approaches that are out of the

scope of the Copernicus Atmosphere services.


Technical annex II: The present report was based on validated CAMS European air quality re-analyses produced by

regional CAMS services thanks to an Ensemble modelling approach. Re-analyses are built upon data

assimilation techniques that allow to account for observations when mapping air pollutant fields. The

validated assessments use validated observation datasets (according to complex quality assurance

protocols compliant with the air quality directives) while interim re-analyses use near-real-time or

up-to-date datasets that are not fully validated, that are generally incomplete (because not all

countries report up-to-date observation data with the same frequency). Interim re-analyses are

generally also issued from older model versions than the validated ones. For these reasons, validated

re-analyses are considered as more robust and more accurate than interim re-analyses.

For the year 2016, both reports have been produced within the framework of the CAMS services.

The 2016 interim assessment report for air quality in Europe was published in July 2017

(CAMS71_2016SC2_D71.1.1.6_201707_2016IAR).

We propose below few quality indicators showing the differences between the interim (IRA) and the

validated (VRA) production. It appears to be worthwhile to maintain both production channels since

the VRA production is significantly better, although it comes also significantly later. Therefore, the

IRA production should be considered as a first guess or analysis of what happened during the targeted

year.

To synthesize several statistical indicators on the same graph, Taylor diagrams are used for the various

pollutants. Model results can be compared on the same diagram, a quarter of disk where the

observation reference is represented by the dot on the x-axis. Correlation coefficient is related to the

azimuthal angle; the centered RMS error (RMSE) is displayed by inner arc of circles; and the standard

deviation of the simulated pattern is proportional to the radial distance from the origin. For each

station typology, results issued from the interim re-analyses (IRA) and from validated re-analyses

(VRA) are plotted on the same graphs.

Ozone daily Maximum:

Erreur ! Source du renvoi introuvable. shows the Taylor diagram associated to 2016 IRA and VRA

ensemble re-analyses for the ozone daily maximum. A slight improvement is obtained for all

indicators with VRA simulations whatever the station typology. 1 to 2 µg/m3 are won for the RMS

error and the correlation increases by 1 or 2 points. However, the ozone interim re-analyses provided

quite satisfactory results.


Taylor diagram synthesizing scores for IRA2016 and VRA2016 by station typology for

ozone daily maximum indicator

PM10 and PM2.5 Daily average The differences between interim and validated re-analyses performance scores are more significant

for PM10 PM2.5 indicators than for ozone. The Taylor diagrams presented on Figure 33 and Erreur !

Source du renvoi introuvable. for PM simulations highlight this point. Root mean square error for

validated re-analyses are lower by 1-3 µg/m3 compared to the interim ones. Same conclusions hold

for correlation coefficients with a significant improvement of the indicator for PM10validated re-

analyses (of about 5 %) but also for PM2.5 even if it is a bit lower. Impact on the air pollution patterns

can be high as illustrated by Figure 35 which shows the number of days when the daily limit value was

exceeded in 2016 according to the interim and the validated re-analyses respectively. Large

underestimation of the interim assessment, especially in the Pô Valley and in Central Europe is clearly

compensated by assimilation of new data in the validated assessment.



PM10 daily average


PM2.5 daily average


Number of days when daily average exceeded 35 µg/m3 in 2016 simulated by CAMS

Ensemble model: interim re-analyses (left) and validated re-analyses (right)


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