Presentation on theme: "1 Hazy vista in the Appalachians. 2 Major Air Pollutants in the Mid- Atlantic United States Bebhinn Do Meteorologist, NC DAQ Some slide material provided."— Presentation transcript:
3 Did You Know? Air quality is getting better in many Eastern U.S. cities? Philadelphia: 68% improvement New York: 64% improvement Baltimore: 52% improvement Source: U.S. EPA (2006), comparing 3-year average AQI (early 1980s to early 2000s)
4 Discussion If air quality is getting better, then why is it still a concern?
5 Course Goals By the end of this session, you will be able to Understand the difference between ambient and indoor air pollution Identify the criteria pollutants Identify the pollutants of concern to the Mid-Atlantic U.S. Understand the sources, trends and spatial patterns of some of the criteria pollutant concentrations in the Mid-Atlantic U.S. Understand the sources, patterns, and trends of major air toxics in the Mid-Atlantic U.S.
6 Air Pollution Air pollution is a gas, vapor, or solid that, in the atmosphere, has adverse effects on health, welfare, or the environment Air pollution occurs in the ambient (outdoor) and indoor environments. Some differences: Sources that influence these environments Transport of pollutants Connection between source and point of impact (receptor)
7 Criteria Air Pollutants are a group of very common air pollutants regulated by EPA on the basis of criteria (information on health and/or environmental effects of pollution). Criteria air pollutants are widely distributed throughout the country. While there are thousands of air pollutants, the following six are the only Criteria Pollutants Lead Sulfur dioxide Nitrogen dioxide Carbon monoxide Particulate matter Ozone Pollutants National Ambient Air Quality Standards (NAAQS) are set for each by the U.S. EPA in the Clean Air Act
8 Pollutants Of the Criteria Air Pollutants, two are particularly challenging for the Mid- Atlantic U.S. Ozone Particulate
9 Ozone Ozone, O 3 NAAQS: 0.12 ppm (1-hr), 0.08 ppm (8-hr) Sources Not directly emitted Formed in the atmosphere Effects Respiratory stressor Crop and forest damage Trends U.S. average concentration down 20% over past 20 years 40+urban areas routinely exceed the 8-hr standard, many in the Mid-Atlantic U.S.
10 Ozone is created in the atmosphere via a complex combination of sunlight-driven chemical (photochemical) reactions. These many reactions can be summarized as follows, Ozone Reactive volatile organic compounds Three important ingredientsOzone
12 Particulate Matter Understanding particulate matter (PM) is complicated by several factors Many different particle sizes Different sources Different composition An old standard was based on Total Suspended Particulate (TSP), those between 0.1 and 30 µm Two air quality standards by particle size PM 10 (Coarse): < 10 µm PM 2.5 (Fine): < 2.5 µm human hair (100 µm) 10 µm PM 2.5 µm PM
13 Coarse particles, PM 10 NAAQS: 150 µg/m 3 (24-hr), 50 µg/m 3 (annual) Major sources Windblown dust Earthmoving Effects Cardiovascular distress Respiratory distress Visibility impairment Trends U.S. average PM 10 down 30% (over past 20 years) While exceedances exist elsewhere, the Mid-Atlantic U.S. has few problems Particulate Matter Fine particles, PM 2.5 NAAQS: 35 µg/m 3 (24-hr), 15 µg/m 3 (annual) Major sources Diesel engines Power plants Effects Cardiovascular distress Respiratory distress Visibility impairment Trends U.S. average PM 2.5 is down 10% (over past 5 years) Numerous areas exceed standard in the East, particularly the DC to Boston urban corridor
14 Particulate Matter Formation of PM Physical attrition ( µm) Combustion by-products ( µm) Nucleation (0.1-1 µm) Homogeneous nucleation: pre-cursor air pollutants forming PM in the atmosphere (secondary PM) –Sulfur dioxide –Nitrogen dioxide –Ammonia Heterogeneous nucleation: binding to existing particles –Organics –Metals
15 Particulate Matter
16 Ozone & Particulate Matter Why are particulate matter and especially Ozone so problematic? What are some of the challenges to reducing both of these pollutants? Consider that in the Mid-Atlantic U.S., sulfates make up as much as 55% of PM 2.5 ; much of this comes from power plants. Power plants have reduced their sulfur emissions more than 33% in this region over the past decade, yet PM 2.5 concentrations remain nearly the same. How can this be? source:
17 Pollutants While PM and ozone attainment challenges exist, four of the Criteria Air Pollutants are rarely problematic Nitrogen dioxide Sulfur dioxide Carbon monoxide Lead
18 Nitrogen Dioxide Nitrogen dioxide, NO 2 NAAQS: ppm [annual] Some major sources Automobiles (gasoline) Power plants (coal, natural gas) Effects Respiratory problems Contribution to ozone formation Damages waterways through deposition Impairs visibility Trends U.S. average concentration down 20% All urban areas now in compliance Smog and haze persist as problems
19 Sulfur Dioxide Sulfur dioxide, SO 2 NAAQS: 0.14 ppm (24-hr), 0.03 ppm (annual) Some major sources Coal-fired power plants Oil-burning power plants Effects Particle formation Respiratory distress Formation of acid deposition –Damage to infrastructure –Damage to ecosystems Visibility Trends U.S. average concentration down 50% over past 20 years All urban areas meet standard Watersheds in northeast U.S. acidified
20 Carbon Monoxide Carbon monoxide, CO NAAQS: 35 ppm (1-hr), 9 ppm (8-hr) Some major sources Vehicles Power plants Wild fires Wood burning stoves Effects Cardiovascular distress Reduced mental acuity, headaches Enhance smog formation Trends U.S. average concentration down 65% Oxygenated fuels, catalytic converters, and wood burning stoves have helped lower emissions Nationally, a few areas are not in compliance ( )
21 Lead Lead, Pb NAAQS: 1.5 µg/m 3 [quarterly] Some major sources Fuels Smelters, battery manufacturers Effects Neurotoxin Impairs brain development in infants Permanent damage Trends U.S. average down more than 93% over the past 20 years due to changes in gasoline formulations Some localized hot spots still remain Notes Inhalation is main exposure route for adults (lead in particulate matter) Ingestion is main exposure route for children (lead paint, soil) Source: US EPA (2006)
22 Hazardous Air Pollutants (HAPs) Hazardous air pollutants (HAPs) are not covered by ambient air quality standards but which, as defined in the Clean Air Act, may present a threat of adverse human health effects or adverse environmental effects. They tend to be found in “hotspots”, usually near their sources. List of HAPs (EPA = 187, TRI=360) No NAAQS
23 Hazardous Air Pollutants (HAPs) Sources Many possible sources, dependent on specific pollutant Main categories: pesticides, metals, organics Effects –Toxicity varies by pollutant –Health impacts (cancer and non-cancer effects) –Bioaccumulative Trends Many emissions are decreasing due to emission monitoring, auditing, and public reporting of emissions (TRI) Hazardous Air Pollutants
24 Hazardous Air Pollutants TRI emission data reveals spatial patterns for one HAP, mercury, in 2004 due to location of major mercury sources. Total Mercury Emissions (pounds/year) source:
25 Hazardous Air Pollutants Compared to mercury, different spatial patterns for another HAP, benzene, in 2004 are due to different sources. Note emission magnitudes and locations. Total Benzene Emissions (pounds/year)
26 Indoor air pollution is different than ambient (outdoor) pollution Sources are often very different for indoor pollutants Carbon monoxide Formaldehyde Particulate matter Nitrogen oxides Ozone Radon Volatile organics Pollutants linger longer due to limited air exchange Indoor air quality is rarely monitored Limited enforcement of air quality in most indoor settings fireplace, stove, furnace, cigarettes carpets, paneling, press board, cigarettes tobacco smoke, cooking, pets, dusting gas stove, kerosene heater photocopier, printer, air cleaners diffuses from soil paint, solvents Indoor Air
27 Any Questions? Thanks for making this a great class!
28 Post Test 1.What pollutant presents the biggest challenges in the Mid-Atlantic U.S.? a)Sulfur dioxide b)Carbon monoxide c)Ozone d)Lead 2.Which is not a source of PM 2.5 ? a)Windblown dust b)Diesel engines c)Coal-fired power plants d)Unpaved roads 3.Which pollutant most recently received a lower NAAQS? a)Ozone b)Carbon monoxide c)Fine particles d)Nitrogen dioxide
29 Further Learning The Particle Pollution Report: Current Understanding of Air Quality and Emissions through 2003, EPA 454-R , The Ozone Report - Measuring Progress through 2003, EPA 454/K , A Guide to Mid-Atlantic Regional Air Quality, Part I: The Nature of Air Pollutants, pp MidAtlantic_RegAQ_Final.pdf A Guide to Mid-Atlantic Regional Air Quality, Appendix C: Air Quality Standard and Goals, pp. C1-C4. MidAtlantic_RegAQ_Final.pdf