AIR POLLUTION

Lecture Objectives By the end of this lesson you will be able to:

1. Name some of the problems and costs associated with air pollution

2. List two types of national air quality standards 3. Describe six responsibilities of the EPA as they

pertain to air pollution standards 4. List six principal air pollutants and their health

and environmental effects 5. Describe the nature and source of acid rain,

visibility pollution and toxic air pollutants

Air Pollution & Respiratory Health

The Problem 1990

More than 2.4 billion pounds of toxic pollutants released into the atmosphere.

1991 98 areas exceeded recommended levels for carbon

monoxide 140 million people lived in those areas

70 exceeded recommended levels for particulate matter 50 exceeded recommended levels for sulfur dioxide

Air Pollution & Respiratory Health

Costs Health costs of exposure to outdoor pollutants $40

million up Estimated 50,000 – 120,000 premature deaths Asthma

People experience more than 100 million days of restricted activity

Health costs exceed $4 billion ~ 4,000 people die of asthma

Air Pollution

Clean Air Act Passed in 1970 Amended in 1990

Revised Ozone and Particulate Matter Standards - 1997

Air Pollution Sources of Air Pollution

Stationary Sources Factories, power plants, smelters

Area Sources (smaller stationary sources) Dry cleaners, degreasing operations

Mobile Sources Cars, buses, planes, trucks, trains

Natural Sources Windblown dust, volcanic eruptions

Air Pollution

Clean Air Act Six EPA Responsibilities

Setting national ambient air quality standards (NAAQS) for the six principal pollutants.

Ensuring the standards are met, or attained. Reducing emissions of sulfur dioxide and nitrogen

oxides that cause acid rain. Reducing air pollutants such as particulate matter,

sulfur oxides, and nitrogen oxides that cause visibility impairment across large regional areas.

Air Pollution

Clean Air Act EPA Responsibilities

Ensure that sources of toxic pollutants that cause or may cause cancer, other adverse human health problems or adverse environmental effects are well controlled and risks to public health and the environment are substantially reduced.

Limiting use of chemicals that damage the stratospheric ozone layer, in order to prevent increased levels of harmful ultraviolet radiation.

1997 National Air Quality

Types of National Air Quality Standards “Primary Standards”

Designed to establish limits to protect public health, including health of “sensitive” populations such as asthmatics, children and elderly

“Secondary Standards” Sets limits to protect public welfare, including

protection against decreased visibility and damage to animals, crops, vegetation, and buildings

Air Pollution

Six Principal Pollutants 1. Carbon Monoxide (CO)

Colorless, odorless and at high levels a poisonous gas.

Formed when carbon fuel is not burned completely. Motor vehicle exhaust accounts for ~60% of all CO

emissions nationwide. As much as 95% in cities.

Air Pollution

Carbon Monoxide (CO) Health Effects

Reduces oxygen perfusion to organs and tissues Low levels

Most serious for people suffering from cardiovascular disease

High levels Poisonous Visual impairment, reduced work capacity, reduced

manual dexterity, poor learning ability and difficulty in performing complex tasks

Air Pollution

2. Lead (Pb) Nature and Sources

Past – automotive sources were major contributor Today – highest concentrations are found in the vicinity of

nonferrous and ferrous smelters and battery manufacturers. Health and Environmental Effects

Occurs mainly through inhalation of air and ingestion of Pb in food, water, soil or dust.

Air Pollution

2. Lead (Pb) Health and Environmental Effects

Can adversely affect the kidneys, liver, nervous system, may cause neurological impairments, such as seizures, mental retardation and behavioral disorders

Low doses associated with damage to the nervous systems of fetuses and young children, resulting in learning deficits and lowered IQ.

May be a factor in high blood pressure and subsequent heart disease

Air Pollution

3. Nitrogen Dioxide (NO2) Nature and Sources

A reddish brown, highly reactive gas that is formed in the ambient air through the oxidation of nitric oxide (NO).

Plays a major role in the formation of ozone. Major source of man-made are emissions are high-

temperature combustion processes – automobiles and power plants.

Air Pollution

3. Nitrogen Dioxide (NO2) Health and Environmental Effects

Short term exposure (less than 3 hrs.) Changes in airway responsiveness and lung function in

individuals with pre-existing respiratory illnesses and increases in respiratory illnesses in children.

Long term exposure may lead to increased susceptibility to respiratory infection and may cause alternations in the lung.

Atmospheric transformation of nitrogen oxides (NOX) can lead to the formation of ozone and nitrogen-bearing particles.

Air Pollution

4. Ground-Level Ozone (O3) Nature and Sources

Primary constituent of smog Is not emitted directly into the air but rather is formed by the

reaction of VOCs (volatile organic compounds) and NO2 in the presence of heat and sunlight.

Forms readily in the atmosphere, usually during hot summer weather.

Air Pollution 4. Ground Level Ozone (O3)

Health and Environmental Effects Short term (1 – 3 hours) Exposure

Repeated exposures make people more susceptible to respiratory infection and aggravate pre-existing respiratory diseases.

Decreases lung function and increases respiratory symptoms such as chest pain and cough.

Long-term (6 – 8 hours) Exposure Present the possibility of irreversible changes in the

lungs which can lead to premature aging of the lungs and/or chronic respiratory illnesses.

Air Pollution 5. Particulate Matter (PM – 10)

Nature and Sources Particulate matter (PM) is a general term used for a mixture

of solid particles and liquid droplets found in the air. Some can be seen in smoke or soot while others can only

be viewed under an electron microscope.. Fine Particles (PM – 2.5)

Result from fuel combustion from motor vehicles, power generation, industrial facilities, residential fireplaces and wood stoves. Gases such as sulfur oxide, SO2, NO2 and VOC interact with other compounds in the air to form fine particles.

Coarse Particles (PM – 10) Result from vehicles traveling on unpaved roads,

materials handling, crushing and grinding operations as well as windblown dust.

Air Pollution 5. Particulate Matter

Health and Environmental Effects Exposure to coarse particles is primarily associated

with the aggravation of respiratory conditions such as asthma.

Fine particles are more closely associated with such health effects as increased hospital admissions and emergency room visits for heart and lung disease, increased respiratory symptoms and disease, decreased lung function and premature death. Elderly individuals with cardiopulmonary disease and

children are at the greatest risk. PM is the major cause of reduced visibility in many

parts of the United States.

Air Pollution

6. Sulfur Dioxide (SO2) Nature and Sources

Gases formed when fuel containing sulfur (mainly coal and oil) is burned and during metal smelting and other industrial processes.

Health and Environmental Effects High concentrations can result in temporary breathing

impairment for asthmatic children and adults who are active outdoors. Short term exposures to elevated levels may result in

reduced lung function accompanied by wheezing, chest tightness and shortness of breath

Air Pollution

6. Sulfur Dioxide (SO2) Health and Environmental Effects

Longer term exposure of high levels of SO2, in conjunction with high levels of PM, include respiratory illness, alternations in the lungs’ defenses and aggravation of existing cardiovascular disease.

Together SO2 and NOX are the major precursors to acidic deposition (acid rain)

Sulfur dioxide is also a major precursor to PM 2.5

Air Pollution

Additional Pollution Concerns Acidic Deposition or Acid Rain

Nature and Source Occurs when sulfur dioxide and oxides of nitrogen in the

atmosphere react with water, oxygen and oxidants to form acidic compounds.

Components can be dry (gas or particles) or wet in the form of rain, snow or fog.

In U.S. ~64% of annual SO2 emissions and 26% of NOX emissions are produced by electric utility plants that burn fossil fuels.

Air Pollution

Additional Pollution Concerns Acidic Deposition or Acid Rain

Health and Environmental Effects Before falling to earth, SO2 and NOX gases and related

particulate matter contribute to poor visibility. Acid rain raises the acid levels in soils and water bodies

(making the water unsuitable for some fish and other wildlife) and damages trees at some elevations. Also speeds the decay of buildings, statues and

sculptures

Air Pollution Visibility

Visibility impairment occurs as a result of the scattering and adsorption of light by air pollution, including particles and gases.

Nature and Sources of the Problem Primary emissions (particles) such as dust from roads

or elemental carbon (soot) from wood combustion. Secondary emissions (particles) are formed in the

atmosphere from primary gaseous emissions Sulfate from sulfur dioxide Nitrates from nitrogen oxides

Air Pollution Reduced Visibility

In eastern U.S. mainly attributable to secondarily formed particles

Western U.S. largely mainly attributable to primary particles

Humidity can significantly increase the effect of pollution on visibility Sulfates can accumulate water and grow in size

reducing visibility more. Annual average relative humidity - in eastern U.S.

70-80%; in western U.S. 50-60% Poor summer visibility in the east primarily the result

of high sulfate conc. combined with high humidity

Air Pollution Toxic Air Pollutants

Those pollutants that cause or may cause cancer or other serious health effects such as reproductive effects, birth defects, or adverse environmental and ecological effects.

Nature and Sources EPA addresses 188 toxic air pollutants Examples include: benzene (found in gasoline),

perchloethylene (emitted from dry cleaning facilities), methylene chloride (solvent and plant stripper)

Also includes natural sources such as volcanic eruptions and forest fires.

Most originate from human-made mobile sources (cars, trucks, etc.) and stationary sources (factories, refineries, power plants)

Air Pollution

Toxic Air Pollutants Health and Environmental Effects

Exposure at sufficient concentrations and duration increases the risk of cancer damage to the immune system neurological damage reduced fertility developmental problems respiratory problems

Air Pollution

Toxic Air Pollutants Health and Environmental Effects

Persistent toxic air pollutants can accumulate in plants and animals magnifying up the food chain A particular concern in aquatic ecosystems where

greater magnification can occur In animals

toxic pollutants disrupt the endocrine system decreased fertility decreased hatching success damaged reproductive organs Altered immune systems

Air Pollution Stratospheric Ozone

Stratosphere - 6 to 30 miles about earth, contains a layer of ozone gas that protects living organisms from harmful ultraviolet radiation (UV-b) from the sun

Nature and Source of Problems Damage has occurred over the past two decades

Ozone hole forms over the Antarctic each year and ozone levels fall to 70% below normal

In U.S. ozone levels are ~5% below normal in the summer and 10% in the winter

3.4% decrease per decade in average total ozone over the northern hemisphere mid-latitudes since 1979

Air Pollution

Stratospheric Ozone Nature and Sources of Problem

in 1996 - scientists demonstrated that UV-b levels over most populated areas increased. Increases associated with human activities including

use of chlorofluorcarbons (CFCs), halons, carbon tetrachloride and methyl chloroform.

These chemicals are found in home air conditioners, foam cushions, etc.

Air Pollution

Health and Environmental Effects Humans

UV-b linked to skin cancer including melanoma Cataracts Suppression of the immune system

Plants Slowed growth Suggestions that marine phytoplankton are already

under stress

Air Pollution

Global Warming and Climate Change Climate is fueled by the sun. Most solar radiation is

absorbed by the earth, some is reflected back into space. Atmospheric gases absorb some of the reflected radiation and reflects more still back to the earth where it warms the earth’s surface in a greenhouse effect. Without the greenhouse effect the earth would be much

colder and probably covered with ice.

Air Pollution Global Warming and Climate Change

Nature and Source of Problems Recent scientific evidence indicates that the greenhouse

effect is increasing. Due to release of certain gases to the atmosphere causing

a rise in temperature - Global warming Carbon dioxide accounts for 85% of greenhouse gases in

the US Methane emissions is the second largest contributor Other contributing gases include hydrofluorocarbons (from

foam production, dry cleaning, chemical and semiconductor manufacturing), perfluorinated compounds (smelting aluminum); nitrogen oxides (automobile exhaust) contribute to ground level ozone

Air Pollution Health and Environmental Effects

Greenhouse emission gases could cause a 1.8o to 6.3oF rise in temperature during the next century if levels are not reduced. Small change that could produce extreme weather events

including droughts and floods, raising sea levels, increased risk for certain disease by producing new breeding sites. Possible increased insect populations and plant disease.

All of these could reduce biological diversity.

Air Pollution

Conclusion Six Principal Pollutants

1. Carbon monoxide 2. Lead 3. Nitrogen dioxide and Nitrogen oxides 4. Ozone 5. Particulate matter (PM-10) and PM-2.5) 6. Sulfur Dioxide and Sulfur oxides

Air Pollution

Conclusion Other Pollutants

Chloroflurocarbons Methane Carbon dioxide Hydrofluocarbons Nitrous oxide Perfluorinated carbons Volatile organic compounds

Air Pollution

Conclusion The Clean Air Act has been the impetus for

improvements in the quality of air in the U.S. New data helps to identify sources of pollution

and their properties. Although a lot of progress has been made we

must change our lifestyles to reduce pollution