1Hazy vista in the Appalachians

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Major Air Pollutants in the Mid-Atlantic United States

Bebhinn DoMeteorologist, NC DAQ

Some slide material provided through K.G. Paterson, Ph.D., P.E. ©2007 via contract with MARAMA

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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)

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Discussion

If air quality is getting better, then why is it still a concern?

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Course GoalsBy 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.

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Air PollutionAir 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)

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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 AmbientAir Quality Standards(NAAQS) are set for each by the U.S. EPA in the Clean Air Act

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Pollutants

Of the Criteria Air Pollutants, two are particularly challenging for the Mid-Atlantic U.S.OzoneParticulate

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OzoneOzone, O3

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.

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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

NOx VOC sunlight O3 other

Reactivevolatile organic compounds

Three important ingredients Ozone

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Ozone

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Particulate MatterUnderstanding 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 PM10 (Coarse): < 10 µm PM2.5 (Fine): < 2.5 µm

human hair(100 µm)

10 µm PM

2.5 µm PM

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Coarse particles, PM10

NAAQS: 150 µg/m3 (24-hr),50 µg/m3 (annual)

Major sources• Windblown dust• Earthmoving

Effects • Cardiovascular distress• Respiratory distress• Visibility impairment

Trends• U.S. average PM10 down 30%

(over past 20 years)• While exceedances exist

elsewhere, the Mid-Atlantic U.S. has few problems

Particulate MatterFine particles, PM2.5

NAAQS: 35 µg/m3 (24-hr),15 µg/m3 (annual)

Major sources• Diesel engines• Power plants

Effects • Cardiovascular distress• Respiratory distress• Visibility impairment

Trends• U.S. average PM2.5 is down 10%

(over past 5 years)• Numerous areas exceed standard

in the East, particularly the DC to Boston urban corridor

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Particulate MatterFormation of PM

Physical attrition (10-1000 µm) Combustion by-products (1-1000 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

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Particulate Matter

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Ozone & Particulate MatterWhy 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 PM2.5; 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 PM2.5 concentrations remain nearly the same. How can this be?

source: http://www.epa.gov/airtrends/pm.html

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Pollutants

While PM and ozone attainment challenges exist, four of the Criteria Air Pollutants are rarely problematicNitrogen dioxideSulfur dioxideCarbon monoxideLead

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Nitrogen DioxideNitrogen dioxide, NO2

NAAQS: 0.053 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

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Sulfur DioxideSulfur dioxide, SO2

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

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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 helpedlower emissions

• Nationally, a few areas are not in compliance (2001-2002)

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LeadLead, Pb

NAAQS: 1.5 µg/m3 [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)

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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

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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

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Hazardous Air PollutantsTRI emission data reveals spatial patterns for one HAP,

mercury, in 2004 due to location of major mercury sources. Total Mercury Emissions (pounds/year)

source: http://www.epa.gov/triexplorer/

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Hazardous Air PollutantsCompared 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)

http://www.epa.gov/triexplorer/

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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, dustinggas stove, kerosene heater

photocopier, printer, air cleaners

diffuses from soilpaint, solvents

Indoor Air

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Any Questions?

Thanks for making this a great class!

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Post Test

1. What pollutant presents the biggest challenges in the Mid-Atlantic U.S.? a) Sulfur dioxideb) Carbon monoxidec) Ozoned) Lead

2. Which is not a source of PM2.5?a) Windblown dustb) Diesel enginesc) Coal-fired power plantsd) Unpaved roads

3. Which pollutant most recently received a lower NAAQS?a) Ozoneb) Carbon monoxidec) Fine particles

d) Nitrogen dioxide

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Further Learning

The Particle Pollution Report: Current Understanding of Air Quality and Emissions through 2003, EPA 454-R-04-002, http://www.epa.gov/airtrends/pm.html

The Ozone Report - Measuring Progress through 2003, EPA 454/K-04-001, http://www.epa.gov/air/airtrends/aqtrnd04/ozone.html

A Guide to Mid-Atlantic Regional Air Quality, Part I: The Nature of Air Pollutants, pp. 1-15. http://www.marama.org/reports/Guide-MidAtlantic_RegAQ_Final.pdf

A Guide to Mid-Atlantic Regional Air Quality, Appendix C: Air Quality Standard and Goals, pp. C1-C4. http://www.marama.org/reports/Guide-MidAtlantic_RegAQ_Final.pdf