Effects and Sources of Air Pollutants

CE 524January 2011

Slides noted as AWMA are from: Understanding Air Quality from the Air and Waste Management AssociationDo not make copies of these slides for distribution

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

Definition of air pollution “Air pollution maybe defined as the

presence in the outdoor and/or indoor atmosphere of one or more contaminants or combinations thereof in such quantities and of such duration as may be or may tend to be injurious to human, plant, or animal life, or property of which unreasonably interferes with the comfortable enjoyment of life or property or conduct of business.

Categories of air pollution

Outdoor Indoor Occupational Personal exposure

General classification of air pollutants

Particulate matter SOx NOx Organic compounds CO Halogen compounds Radioactive compounds Photochemical oxidants Other inorganic compounds

What about GHGs, ozone, biological agents?

Air Quality Criteria Based on levels to protect human health

Sensitive members of the population Developed based on relationship between exposure and

short and long-term health and welfare effects Effects are expected to occur when pollutant levels exceed

criteria for specified time period Short-term -- immediate protection Chronic exposure

Pollutant levels cannot legally be exceeded during specific time period in a specific geographical area

National Emission Standards Limit amount or concentration of pollutant

emitted from a source Helps maintain or improve existing air

quality in a region to meet state or local standards

Based on what is achievable with current technology

Basis for Regional Standards Availability of technology Presence of monitoring stations Ability to enforce standards Understanding of synergistic effects of different

pollutants Preparation of dispersion model (predicting

ambient concentrations) Accurate estimates of growth or decline in

industry or population

Criteria AirPollutants

• Carbon Monoxide (CO)

• Hydrocarbons

• Oxides of Nitrogen (NOx)

• Sulfur Dioxide (SO2)

• Particulate Matter (PM10)

• Lead (Pb)

Fundamentals of Air Pollution and Motor Vehicle Emissions

John T. White, EPA

Current NAAQSPollutant Averaging

TimePrimary Standard

Secondary StandardCO

8 hr 9 ppm Same1 hr 35 ppm Same

NO2 Annual average 0.05 ppm NoneSO2 Annual average 0.03 ppm None

24 hr 0.14 ppm None3 hr None 0.5 ppm

PM10 Annual arithmetic mean

50 g/m3 Same

24 hr 150 g/m3 SamePM2.5

Added 1997

Annual arithmetic mean

15 g/m3 Same 

24 hr 150 g/m3 SameOzone 1 hr 0.12 ppm Same

 8 hr 0.08 ppm Same

Lead 3 months 1.5 g/m3 same

Hydrocarbons Result when fuel molecules in the engine do not

burn or only partially burn React in the presence of nitrogen oxides and

sunlight to form ground-level ozone, a major component 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 also toxic, with the potential to cause cancer.

Source: EPA 400-F-92-007 August 1994 Fact Sheet OMS-5

Particulate matter

Dispersed airborne solid and liquid particles (specific size criteria in chapter)

Settles out of air at rate which is function of size and weight (measured in micrometer µ = 10-4 cm)

Dust, water vapor, etc Affect health and visibility

ParticulateMatter(PM10)

Also regulating

PM2.5

• PM10 is a general term for tiny airborne particles (under ten microns), 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 by meteorological 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 mechanisms

which clear the respiratory tract Particle may act as carrier of absorbed toxic

substance 20 to 60% of particles between 1 and 2.5 µm

breathed will penetrate into lungs• Enter deep tissue

SulfurDioxide(SO2)

Sulfur trioxide

• This term is used for a number of compounds containing sulfur

• Primarily caused by burning of coal, oil and various industrial processes

• They can affect the respiratory system

• They react in the atmosphere to form acids, sulfates and sulfites

• Substantial reductions due to controls at the sources and through use of low sulfur fuels

Make up 5 to 20% of total suspended particles Major damage to materials Contributes to acid rain

Fundamentals of Air Pollution and Motor Vehicle Emissions

John T. White, EPA

Oxidesof Nitrogen(NOx)

• Nitrogen dioxide is the prominent one (it's the yellow-brown color in smog)

• NOx results from high temperature combustion processes, e.g. cars and 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 high concentrations (> 750 ppm)

Hemoglobin has 240 times affinity for CO as for 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

Lead(Pb)

• Long known as one of the worst toxics in common use

• Emitted from gasoline additives, battery factories and non-ferrous smelters

• Affects various organs and can cause sterility and neurological impairment, e.g. retardation and behavioral disorders

• Infants and children especially susceptible

• Control of mobile sources has been exceptionally successful

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

Climate Change• Certain gases in the

troposphere absorb some of the infrared radiation reflected from the earth

• Carbon Dioxide is the major one (50%).

• Others include methane (18%) and CFCs (14%). CFCs also are responsible for destroying the stratospheric ozone layer

• The United States produces over 20% of the world's "greenhouse" gases

Fundamentals of Air Pollution and Motor Vehicle Emissions

John T. White, EPA

TheExtentofAirPollutionToday Overall, 54 million metric

tons from mobile sourcesin 1990 (43% of total)

Mobile SourcesStationarySources

CO

VOCsNOx

SO2

LeadPM10

Fundamentals of Air Pollution and Motor Vehicle Emissions

John T. White, EPA

Who isAffected byAir Pollution?

63

22

9

19

15

Ozone CO NO2 PM10 SO2 Lead

Millions of people living in counties with air quality that exceeds each NAAQS (1990 data)

Over 74 million people are subjected to high levels of at least one of these pollutants

Fundamentals of Air Pollution and Motor Vehicle Emissions

John T. White, EPA

World wide

WHO indicates that 2.4 million people die from causes directly attributable to air pollution

More than for car accidents

Visibility

Although not a pollutant, visibility is a major pollution concern

Haze Smog

Air Toxics

Get information from EPA Example - http://epa.gov/otaq/toxics.htm

When is it a problem

Classified as pollutant once their presence results in damage to humans, plants, animals or materials

Concentration 1 volume of gaseous pollutant = 1 ppm106 volumes (pollutant + air)

0.0001 percent by volume = 1 ppm