Effects and Sources of Air Pollutants - Air Pollution - Lecture Slides, Slides of Ecology and Environment

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Effects and Sources of AirPollutants

Major Provisions of 1970 CAAA ^

Established NAAQS^ 

Primary – allows adequate margin of safety to protect public health  Secondary – protects public from effects of air pollution

-^

Plants, animals, visibility, public enjoyment of life & property

^

Set new source performance standards for new stationary sources ^

National Emission Standards for Hazardous Air Pollutants(NESHAPS) applied to existing and new plants ^

Required states to submit

state implementation plans

(SIPs)

^

Method to set AQ standards for air quality regions within state

Categories of air pollution 

Outdoor

Indoor

Occupational

Personal exposure

General classification of airpollutants

^

Particulate matter ^

SOx ^

NOx ^

Organic compounds ^

CO ^

Halogen compounds ^

Radioactive compounds ^

Photochemical oxidants ^

Other inorganic compounds^ 

What about GHGs, ozone, biological agents?

National Emission Standards 

Limit amount or concentration of pollutantemitted from a source

Helps maintain or improve existing airquality in a region to meet state or localstandards

Based on what is achievable with currenttechnology

Basis for Regional Standards 

Availability of technology



Presence of monitoring stations



Ability to enforce standards



Understanding of synergistic effects of differentpollutants



Preparation of dispersion model (predictingambient concentrations)



Accurate estimates of growth or decline inindustry or population

Current NAAQS

Pollutant

Averaging Time

Primary Standard

Secondary Standard

CO

8 hr

9 ppm

Same

1 hr

35 ppm

Same

NO

2

Annual average

0.05 ppm

None

SO

2

Annual average

0.03 ppm

None

24 hr

0.14 ppm

None

3 hr

None

0.5 ppm

PM

10

Annual arithmeticmean

50



g/m

3

Same

24 hr

150



g/m

3

Same

PM

2. Added 1997

Annual arithmeticmean

15



g/m

3

Same

24 hr

150



g/m

3

Same

Ozone

1 hr

0.12 ppm

Same

8 hr

0.08 ppm

Same

Lead

3 months



g/m

3

same

Hydrocarbons ^

Result when fuel molecules in the engine do notburn or only partially burn



React in the presence of nitrogen oxides andsunlight to form ground-level ozone, a majorcomponent of smog



Ozone irritates the eyes, damages the lungs,and aggravates respiratory problems^ 

most widespread urban air pollution problem.



A number of exhaust hydrocarbons are alsotoxic, with the potential to cause cancer.

Source:

EPA 400-F-92-007 August 1994 Fact Sheet OMS-

P

articulate

Matter(PM

Also regulatingPM

-^

PM10 is a general term for tinyairborne particles (under tenmicrons), e.g., dust, soot, smoke

• Primary sources are fuel-burning

plants and other industrial/commercial processes

• Some are formed in the air• They irritate the respiratory system

and may also carry metals,sulfates, nitrates, etc.

• Some overall decreases seen but

trends may be masked bymeteorological changes

Fundamentals of Air Pollution and Motor Vehicle Emissions John T. White, EPA

Health Effects of PM 

Particles directly enter respiratory system



Particles themselves may be toxic



Particle may interfere with mechanismswhich clear the respiratory tract



Particle may act as carrier of absorbed toxicsubstance



20 to 60% of particles between 1 and 2.5 μmbreathed will penetrate into lungs

• Enter deep tissue

Oxidesof Nitrogen(NOx)

• Nitrogen dioxide is the prominent

one (it's the yellow-brown color insmog)

• NOx results from high temperature

combustion processes, e.g. carsand utilities

• They affect the respiratory system• They play a major role in atmos-

pheric reactions

• Overall levels unchanged but

transportation sources are cleaner

Fundamentals of Air Pollution and Motor Vehicle Emissions John T. White, EPA

CarbonMonoxide(CO)

-^

Odorless, colorless gas

• Caused by incomplete combustion of fuel and

air

• Most of it comes from motor vehicles• Reduces the transport of oxygen through the

bloodstream ^

Poses immediate health risk in highconcentrations (> 750 ppm) ^

Hemoglobin has 240 times affinity for CO asfor oxygen

• Affects mental functions and visual acuity,

even at low levels

• Improvements are being made but there are

still problems in some urban areas

Fundamentals of Air Pollution and Motor Vehicle Emissions John T. White, EPA

OtherAirPollutants

• Carbon dioxide• Chlorofluorocarbons• Formaldehyde• Benzene• Asbestos• Manganese• Dioxins• Cadmium• Still others which are yet to be

fully characterized

Fundamentals of Air Pollution and Motor Vehicle Emissions John T. White, EPA

Categories of Air Pollution ^

Ambient:^ 

air pollution in outdoors  Focus of class  Regulated by EPA

^

Indoor^ 

Air pollution indoors, buildings  EPA studies issues but no federal regulations

^

Occupational^ 

Pollutants in the workplace (mining, chemical operations,etc)  Regulated by OSHA

^

Personal exposure^ 

Persons willful exposure  Cigarette, gases, etc