1 Pollutants of Concern in North America and

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, Croatia May 24, 2007

2 Objectives • Identify air pollutants and reasons for concern • Describe different approaches to improving air quality

Several air pollutant categories and concerns 3 • Criteria Pollutants – indicators of air quality with maximum concentrations above which adverse effects on human health may occur (CO, SO 2, NO 2, O 3, Pb, PM [TSP, RSP, PM 10, PM 2. 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 (H 2 SO 4, HNO 3, O 3)

Several air pollutant categories and concerns 4 • Material Damage – reactive or decolorizing pollutants that destroy or soil buildings, clothing, vehicles, antiquities (SO 2, H 2 SO 4, HNO 3, 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

Several air pollutant categories and concerns • Visibility Reducing Gases and PM – PM 2. 5 components, including sulfate, nitrate, ammonium, organic carbon, elemental carbon, sea salt, and soil. NO 2 absorbs light in plumes • Halocarbons – deplete stratospheric O 3 (Freon-12, SF 6, 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 (CO 2, CH 4, halocarbons, BC, ultrafine particles) 5

Same pollutants in several categories 6 • Many pollutants are in several regulatory categories (e. g. , SO 2, NOx, VOCs, SO 4=, NO 3 -, 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): O 3, secondary sulfates and nitrates – Regional-scale (100 to 1, 000 km): O 3, 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

7 Several 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

8 Ambient air quality standards are basis for regulation Pollutant EU Std CO 10 mg/m 3 8 hr max/day 0/yr 10 mg/m 3 40 mg/m 3 8 hr 1/yr SO 2 350 µg/m 3 125 µg/m 3 1 hr 24/yr 365 µg/m 3 80 µg/m 3 24 hr 1 yr 1 0 NO 2 200 µg/m 3 40 µg/m 3 1 hr 1 yr 18/yr 0/yr 100 µg/m 3 1 yr 0 120 µg/m 3 8 hr max/day 25/3 -yr 160 µg/m 3 8 hr max/day 4 th 3 -yr avg 50 µg/m 3 40 µg/m 3 24 hr 1 yr 35/yr 0/yr 150 µg/m 3 24 hr 2 nd 3 -yr avg 35 µg/m 3 15 µg/m 3 24 hr 3 yr 98% 0/3 yr . 25 yr 0/quarter O 3 PM 10 EU Avg EU Exced US Std PM 2. 5 None TSP Pb 0. 5 µg/m 3 1 yr 0/yr 1. 5 µg/m 3 Benzene 0. 5 µg/m 3 1 yr 0/yr HAPs As 120 µg/m 3 1 yr 0/yr HAPs Cd 5 ng/m 3 1 yr 0/yr HAPs Ni 20 ng/m 3 1 yr 0/yr HAPs PAH (Ba. P) 1 ng/m 3 1 yr 0/yr HAPs US Avg US Exced

Elements of an air quality standard • Evidence of association with adverse health effects • Indicator (e. g. , O 3 for oxidants, PM 2. 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) 9

10 Levels for adverse health differ by pollutant CO has well defined chemical character and health end-point

11 SO 2 is well defined pollutant, but with several health end-points

PM has multiple components and multiple health endpoints The PM-mortality effect estimates are consistently larger for longer time scales of exposure. 12

13 Air quality progress in Europe and the US • CO, SO 2, NO 2, 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 SO 2, NOx, and PM emission controls • On-road diesel engine emissions requirements • Montreal Protocol on fluorocarbon releases • Regional emission caps for industrial SO 2 and NOx

EURO passenger car emissions standards (g/km) 14

15 Problem: O 3 and PM 2. 5 are remaining problems at local and regional levels Counties Exceeding the Ozone and PM 2. 5 NAAQS in 2002 Ozone Nonattainment (226 Counties) PM 2. 5 Nonattainment (49 Counties) Both Nonattainment (71 Counties)

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? 16

Particle Diameter (nm) Ultrafine particles come from primary emitters and form in the atmosphere Vehicle Exhaust Photochemical Nucleation d. N/dlog. Dp (number cm-3) Vehicle Exhaust, Residential Heating and Cooking 17

18 Saharan dust affects southern Europe

Conclusions 19 • Criteria pollutants (CO, SO 2, NO 2, O 3, Pb, and PM [TSP, RSP, PM 10, PM 2. 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, SO 2, NO 2, and Pb, but O 3 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