1

Pollutants of Concern in North America and Europe John G. Watson (john.watson@dri.edu)

Judith C. Chow Desert Research Institute, Reno, NV, USA

presented at

The Workshop on Air Quality Management, Measurement, Modeling, and Health Effects

University of Zagreb

Zagreb, Croatia

May 24, 2007

2

Objectives

• Identify air pollutants and reasons for concern

• Describe different approaches to improving air quality

3Several air pollutant categories and concerns

• Criteria Pollutants

– indicators of air quality with maximum concentrations above which adverse effects on human health may occur (CO, SO2, NO2, O3, Pb, PM [TSP, RSP, PM10, PM2.5])

• Hazardous Air Pollutants (HAPs, or toxics)

– emissions known or suspected to cause cancer or other serious health effects, such as reproductive effects, birth defects, or other adverse environmental effects (many VOCs, metals, PAHs, diesel particles)

• Acid Deposition

– highly oxidizing pollutants that destroy forests, crops, lakes (H2SO4, HNO3, O3)

4Several air pollutant categories and concerns

• Material Damage

– reactive or decolorizing pollutants that destroy or soil buildings, clothing, vehicles, antiquities (SO2, H2SO4, HNO3, O3, soot [BC: black carbon], soil dust)

• Odors

– unpleasant olfactory experiences (reduced sulfur compounds, certain VOCs)

• Mercury

– included in HAPs, but also results in bioaccumulation in lakes and fish through deposition

5Several air pollutant categories and concerns

• Visibility Reducing Gases and PM

– PM2.5 components, including sulfate, nitrate, ammonium, organic carbon, elemental carbon, sea salt, and soil. NO2 absorbs light in plumes

• Halocarbons

– deplete stratospheric O3 (Freon-12, SF6, halon, other fluorocarbons)

• Climate Forcing Gases and PM

– change the Earth’s radiation balance directly by absorbing electromagnetic radiation or indirectly by changing cloud cover and water vapor (CO2, CH4, halocarbons, BC, ultrafine particles)

6Same pollutants in several categories • Many pollutants are in several regulatory categories (e.g.,

SO2, NOx, VOCs, SO4=, NO3

-, BC)

• Several pollutants come from similar activities (coal burning, industrial processes, vegetative burning, transportation, windblown dust)

• Several have similar spatial scales and lifetimes– Microscale (10 to 100 m) and Middle-scale (100 to 500 m): odors, traffic,

HAPs, dustfall

– Neighborhood-scale (500 m to 4 km): vehicle exhaust, residential heating and burning, primary industrial emissions

– Urban-scale (4 to 100 km): O3, secondary sulfates and nitrates

– Regional-scale (100 to 1,000 km): O3, secondary sulfates and nitrates, forest fires, regional haze

– Continental-scale (1,000 to 10,000 km): large scale fires, Asian and Saharan dust

– Global-scale (>10,000 km): greenhouse gases, halocarbons, BC

7Several methods for air pollution control

• Ambient air quality standards• Emission limits (with certification tests)• Effluent treatment requirements (Reasonably Available,

Best Available, Lowest Achievable Emissions Technologies)

• Product design specification• Fuel specifications (with certification tests)• Emission fees and fines• Congestion pricing• Forced shutdowns• Emissions caps and trading• Inspection and Maintenance programs• Energy efficiency requirements• Demonstrated reasonable progress

8Ambient air quality standards are basis for

regulationPollutant

EU Std EU Avg EU Exced

US Std US Avg US Exced

CO 10 mg/m3 8 hr max/day

0/yr 10 mg/m3

40 mg/m3

8 hr1 hr

1/yr1/yr

SO2350 µg/m3

125 µg/m3

1 hr24 hr

24/yr3/yr

365 µg/m3

80 µg/m3

24 hr1 yr

10

NO2200 µg/m3

40 µg/m3

1 hr1 yr

18/yr0/yr

100 µg/m3

1 yr 0

O3 120 µg/m3

8 hr max/day

25/3-yr 160 µg/m3

8 hr max/day

4th 3-yr avg

PM1050 µg/m3

40 µg/m3

24 hr1 yr

35/yr0/yr

150 µg/m3

24 hr 2nd 3-yr avg

PM2.5 None 35 µg/m3

15 µg/m3

24 hr3 yr

98%0/3 yr

TSP Pb 0.5 µg/m3 1 yr 0/yr 1.5 µg/m3 .25 yr 0/quarter

Benzene 0.5 µg/m3 1 yr 0/yr HAPs

As 120 µg/m3

1 yr 0/yr HAPs

Cd 5 ng/m3 1 yr 0/yr HAPs

Ni 20 ng/m3 1 yr 0/yr HAPs

PAH (BaP)

1 ng/m3 1 yr 0/yr HAPs

9

Elements of an air quality standard• Evidence of association with adverse health effects

• Indicator (e.g., O3 for oxidants, PM2.5 for PM) associated with (but not necessarily the only cause of) effects

• Averaging time(s) (some effect acute, others long term)

• Threshold concentration (set to protect public health with a safety margin)

• Form (e.g., number of exceedances allowed)

• Enforcement and penalties (EU has limit values and less strict target values. US has timelines for attainment and potential for sanctions)

10

Levels for adverse health differ by pollutantCO has well defined chemical character and health end-

point

11

SO2 is well defined pollutant, but with several health end-points

12

PM has multiple components and multiple health end-points

The PM-mortality effect estimates are consistently larger for longer time scales of exposure.

13Air quality progress in Europe and the US

• CO, SO2, NO2, and Pb standards are largely met in U.S. and Europe

• Pb no longer used as a fuel additive

• Most sulfur removed from diesel and gasoline fuels

• New industrial sources have SO2, NOx, and PM emission controls

• On-road diesel engine emissions requirements

• Montreal Protocol on fluorocarbon releases

• Regional emission caps for industrial SO2 and NOx

14

* Before Euro V passenger vehicles > 2.500 kg were type approved as Light commercial vehicle N1 - I

Euro VI

0.005b

0.06-0.0751.0Sept. 2009Euro V (proposed)

-0.08-0.101.0Jan. 2005Euro IV

-0.15-0.202.30Jan. 2000Euro III

--0.5-2.2Jan. 1996Euro II

--0.97 (1.13)-2.72 (3.16)July 1992Euro I†

Petrol (Gasoline)

Euro VI

0.0050.180.23-0.50Sept. 2009Euro V (proposed)

0.0250.250.30-0.50Jan. 2005Euro IV

0.050.500.56-0.64Jan. 2000Euro III

0.10-0.9-1.0Jan. 1996a

Euro II, DI

0.08-0.7-1.0Jan. 1996Euro II, IDI

0.14 (0.18)-0.97 (1.13)-2.72 (3.16)July 1992Euro I†

Diesel

PMNOxHC+NOxHCCODateTier

* Before Euro V passenger vehicles > 2.500 kg were type approved as Light commercial vehicle N1 - I

Euro VI

0.005b

0.06-0.0751.0Sept. 2009Euro V (proposed)

-0.08-0.101.0Jan. 2005Euro IV

-0.15-0.202.30Jan. 2000Euro III

--0.5-2.2Jan. 1996Euro II

--0.97 (1.13)-2.72 (3.16)July 1992Euro I†

Petrol (Gasoline)

Euro VI

0.0050.180.23-0.50Sept. 2009Euro V (proposed)

0.0250.250.30-0.50Jan. 2005Euro IV

0.050.500.56-0.64Jan. 2000Euro III

0.10-0.9-1.0Jan. 1996a

Euro II, DI

0.08-0.7-1.0Jan. 1996Euro II, IDI

0.14 (0.18)-0.97 (1.13)-2.72 (3.16)July 1992Euro I†

Diesel

PMNOxHC+NOxHCCODateTier

EURO passenger car emissions standards (g/km)

15

Problem: O3 and PM2.5 are remaining problems at local and regional levels

Ozone Nonattainment (226 Counties)

PM2.5 Nonattainment (49 Counties)

Both Nonattainment (71 Counties)

Counties Exceeding the Ozone and PM2.5 NAAQS in 2002

16

Emerging air quality issues

• Greenhouse gases and particles: How can these emissions be reduced along with other pollutants? How can they be regulated?

• Long-range transport: Emissions from China, India, Latin America, and Africa are rising and affect concentrations in Europe and the U.S. How can these emissions be controlled?

• Multi-pollutant control strategies and effects: Are individual pollutant regulations still adequate?

• Ultrafine particles: Are these the real causes of PM health effects?

• Unintended consequences: How to anticipate people’s reaction to pollution regulations?

17

Hour

0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223

Dia

me

ter (n

m)

10

100

0 10000 20000 40000 50000 30000

Vehicle Exhaust, Residential Heating and Cooking

Photochemical Nucleation

Vehicle Exhaust

Part

icle

Dia

mete

r (n

m)

dN/dlogDp (number cm-3)

Ultrafine particles come from primary emitters and form in the

atmosphere

18

Saharan dust affects southern Europe

19

Conclusions

• Criteria pollutants (CO, SO2, NO2, O3, Pb, and PM [TSP, RSP, PM10, PM2.5]) are the basis for air quality regulation, but they are not the only ones of importance

• Europe and US have successfully reduced exposures to CO, SO2, NO2, and Pb, but O3 and PM are still of concern

• Remaining pollutants have regional sources and require regional strategies for reduction

• Emerging economies (China, India, etc) are increasing emissions, and these affect Europe and the US

• Greenhouse gases and particles that affect climate and ultrafine particles that affect health will become more important pollutants to be regulated in the future