Air Pollution

Air Pollution

Primary Pollutants: Come from:

Natural sources (volcanoes) Mobile sources (cars) Stationary sources (smoke

stacks) Examples:

Particle matter or soot (PM10) Nitric oxide (NO) Nitrogen dioxide (NO2) Sulfur dioxide (SO2) Carbon dioxide (CO2) Carbon monoxide (CO)

Secondary Pollutants: Result from chemical

reactions of primary pollutants in the atmosphere

Examples: Sulfur trioxide (SO3) Sulfuric acid (H2SO4) Ozone (O3)

Major Air Pollutants

Criteria air pollutants Set of pollutants that cause smog, acid rain, and

other health hazards Emitted from industry, mining, transportation,

power generation, and agriculture Include: ozone, particulate matter, carbon

monoxide, sulfur dioxide, nitrogen oxides, and lead

Major Air Pollutants

Nitrogen Dioxide (NO2) Forms when fuels burn at

high temperatures, from forest fires, volcanoes, and bacteria in soil

Forms nitric acid in the air acid deposition

When inhaled irritates the lungs

Supresses plant growth May be a carcinogen

Ozone (O3) Formed by the reaction of

sunlight and NOx and VOCs

Causes: Lung irritation and

damage Bronchial constriction Coughing Wheezing Eye irritation

In high atmosphere forms ozone layer = good

Major Air Pollutants

Peroxyacyl Nitrates (PANs)Hydrocarbons + O2 +NO2 + light CH3COOONO2 (PAN)Stable in the atmosphere transport unstable compounds far away from urban centersCause eye irritation In high concentrations damage vegetation

Sulfur Dioxide (SO2) Produced by burning high-

sulfur oil or coal, smelting of metals, and paper manufacturing

Combines with water vapor to produce acid rain

Acid rain causes: Reduction in plant

productivity Breathing difficulties Destroys buildings Acidifies water supply

Major Air Pollutants Suspended Particulate

Matter (PM10) Particles with a diameter of

1/7 of a human hair or less Include smoke, dust, diesel

soot, lead, and asbestos Cause lung irriation and

damage Are mutagens, teratogens

(interfers with development), and carcinogens

Reducing PM10 would produce health benefits 10 times grater than reducing all other air pollutants combined

Volatile Organic Compounds (VOCs) Include organic compounds

that have a high vapor pressure

Found in paints, aerosol sprays, dry-cleaning fluids, and industrial solvents

Cause respiratory irritation and damage

Most are carcinogens Cause liver, kidney, and

central nervous system damage

May be greater concentrations indoors than outdoors

Measurement Units

ppm (Parts per million) 1ppm means every 999,999 particles of air there

is 1 particle of pollutant

Others: ppb or nano: parts per billion ppt or pico: parts per trillion

Smog

Industrial: tends to be sulfur based Called “grey-air” smog

Photochemical: nitrogen based Catalyzed by UV radiation Called “brown-air” smog

Formation of industrial smogStep Chemical Reaction

1. Carbon in coal or oil is burned in oxygen gas to produce carbon dioxide and carbon monoxide

C + O CO2

C + O CO

2. Unburned carbon ends up as soot or particulate matter

C

3. Sulfur in oil and coal reacts with oxygen gas to produce sulfur dioxide

S + O SO2

4. Sulfur dioxide reacts with oxygen gas to produce sulfur trioxide

SO2 + O2 SO3

5. Sulfur trioxide reacts with water vapor in the air to form sulfuric acid

SO3 + H2O H2 SO4

6. Sulfuric acid reacts with atmospheric ammonia to form brown, solid ammonium sulfate

H2 SO4 + NH3 (NH2)2SO4

Formation of photochemical smog

Occurs during specific times of the day

Net Result:

NO + VOCs + O2 + uv O3 + PANs

Formation of photochemical smog

Time of day

Event Chemical Reactions

6 A.M. – 9 A.M.

People drive to work, concentrations of nitrogen oxides and VOCs increase

N2 + O2 2NO

NO + VOCs NO2

NO2 + uv NO + O

9 A.M. – 11 A.M.

As traffic begins to decrease nitrogen oxides and VOCs react to form nitrogen dioxide

2NO + O 2NO2

Formation of photochemical smog cont.

Time of day Event Chemical Reactions

11A.M. – 4 P.M.

As sunlight becomes more intentse, nitrogen dioxide is broken down and the concentration of ozone increaes

NO2 + uv NO + O

O2 + O O3

Nitrogen dioxide reacts with water vapor to produce nitric acid and nitric oxide

3 NO2 + H2O 2HNO3 + NO

Nitrogen dioxide can also react with VOCs released by vehicles , refineries, gas stations, and so on to produces toxic PANs

NO2 + VOCs PANs

4 P.M. – Sunset

Ozone production is halted

Case Study – Great Smog of ‘52

A period of cold weather combined with windless conditions to collect airborne pollutants (most form coal) to produce a thick layer of grey smog over London December 5 – 9 1952

Dispersed quickly after a change in weather 100,000 people became ill 12,000 died

Catalytic Converters

Converts toxic chemicals in engine exhaust to less noxious substances

Inside a catalyst stimulates a chemical reaction in which noxious by-products of combustion are converted to less toxic substances

Catalytic Converters

3 way converter: Reduction of nitrogen dioxides to nitrogen and oxygen Oxidation of carbon monoxide to carbon dioxide Oxidation of unburned hydrocarbons to carbon dioxide and

water.

Catalytic converters

Pros Remove hydrocarbons

and other harmful emissions

Cons Do not reduce carbon

dioxide emissions Release nitrous oxide

which contributes to climate change

Types of Acid Deposition

Wet: Acid rain Acid fog Acid snow Water flows over the

ground and affects plants and animals

Dry Acid gases Acid particles Particles fall out of

atmosphere and onto buildings, cars, trees, etc.

Rain can wash particles off features in the environment contributing to acid rain

Acid depositions

Due to: Sulfur dioxide Nitrogen oxides

Environmental effects: Acidify streams Damage forests soils through nitrogen saturation Acid shock (rapid melting of snow pack with acid

particles) Leaches essential plant nutrients from the soil

Heat Islands Occur in metropolitan areas Urban air is 10°F (6°C) warmer than surrounding

environment

Heat Islands Causes:

Buildings reduce radiation of heat to the atmosphere

Thermal properties of surface material (asphalt, bricks, concrete) store heat longer

Lack of vegetation and standing water increase temperatures

Human activities (automobiles, industry, etc.)

Effects: Combined with high

levels of pollution leads to a localized green house effect

Excessive temperatures can lead to deaths

Meteorological effects: Alter local wind patterns Alter the development

of clouds and fog Alter number of lighting

strikes Change precipitation

patterns

Wind and Urban Heat Islands

Combating urban heat islands

Increasing amount of landscaping in parks and on top of buildings

Increasing the amount of light or reflective material

Smart Cities

Temperature Inversions

Occur when air temperature increases with height above the ground Usually occur at night when the surface cools,

cooling the air above it

Can lead to smog being trapped near the ground human health problems (asthma, emphysema, and increase in lung cancer)

Case Study- Donora, PA 1948

Smog from the local zinc and steel smelting plants settled in the valley where Donora was located

20 people asphyxiated and 7,000 went to the hospital (total population of the town was 14,000)

Four days later, wind cleared the toxins from the town

Led to first meaningful federal and state laws to control air pollution

Indoor Air Pollution

Indoor air pollution is 25% to 60% greater than outdoor pollution

Sick Building Syndrome (SBS) describes a combination of ailments associated with a place of work or residence

Common Pollutants: Mold Bacteria Carbon monoxide Radon Allergens Asbestos Tobacco smoke Formaldehyde VOCs

SBS symptoms

Headaches Breathing difficulties Allergies Asthma Cancer Emphysema Nerve disorders

Air Pollution Remediation and Reduction Strategies

1. Emphasizing tax incentives for pollution control rather than fines and penalties

2. Setting legislative standards for energy efficiency

3. Increasing funding for research into renewable energy resources

4. Incorporating incentives for reducing air pollution into trade policies

5. Distributing solar cook stoves to developing countries to replace coal and firewood

Air Pollution Remediation and Reduction Strategies

6. Phasing out two-cycle gasoline engines7. For issues involving SBS

a. Modify building codes to control materials used in construction

b. Replace and repair areas that have received water damage to control for mold

c. Use paints, adhesives, solvents, cleaning products, and pesticides in well-ventilated areas and during non-occupancy

d. Increase the number of complete air exchanges in buildings

e. Ensure proper maintenance of HVAC systems8. Providing incentives to use mass transit

Combating Acid Rain

Design more efficient engines to reduce emissions

Reduce emissions in coal-burning power plants

Increase penalties on stationary sources Provide incentives to consumers to purchase

Energy Star products Increase CAFE standards

EPA’s Acid Rain Program Designed to achieve

significant environmental reduction and public health benefits through reductions in emission of sulfur and nitrogen compounds at a low cost to society

Encourages energy efficiency and pollution prevention

Strategies: Allowance trading system Opt-in program, allows non-

affected industrial and small utility units to participate in trading

Setting new NOx emission standards

Permit process that affords flexibility in selecting most cost-effective approach

Continuous Emissions Monitoring (CEM) provide accounting of excess emissions

Clean Air Act (1963) Designed to control

pollution on a national level Act has been amended in

1967, 1977, 1990 Requires EPA to design and

enforce regulations to protect the public from airborne contaminants

Required comprehensive federal and state regulations for both stationary and mobile sources of pollution

Expanded federal enforcement authority

Addressed acid rain, ozone depletion, and toxic air pollution

Established new gasoline reformulation requirements

1st major environmental law to include provisions for citizen law suits

Clean Air Act (1963) is responsible for:

Estimates responsible for: Saving 15,000 lives per

year Reducing bronchitis by

60,000 cases each year Reducing respiratory

related illnesses by 9,000 cases each year

Pollutant Changes

Pollutant % Change

Pb (lead) -98%

VOC -42%

SO2 -37%

CO -31%

NOx +17%

PM10 +266%

Relevant laws

Air Pollution Control Act (1955) 1st legislation regarding air pollution Identified air pollution as a national problem Announced research and additional steps were

necessary Basically meant to make public aware of problem

National Environmental Policy Act (1970) Created EPA Mandated the creation of Environmental Impact

Statements

Relevant laws

Montreal Protocol (1989) Agreement among nations to phase out

chemicals that damage the ozone layer

Pollution Prevention Act (1990) Requires industry to reduce pollution at its source Reduction can be in terms of volume and/or

toxicity

Kyoto Protocol (1997 and 2001) An agreement among 150 nations requiring

greenhouse gas reductions Would have required a 7% decrease in greenhouse

gas emissions compare to 1990 levels over a 5 year period US felt protocol held developed and developing countries

to different standards Concerned the costs were too high and time frame too

short; climate change deniers 2012: Canada, Japan, and Russia joined the US

saying they would not sign an agreement unless unbalanced requirements for developed and developing countries were changed

Noise Pollution

Unwanted human-created sound that disrupts the environment Transportation noise (dominant) Office equipment Factory machinery Appliances Power tools Audio entertainment systems

Noise Pollution Effects

Short Term Damage to inner ear

results in hearing loss Cardiovascular problems Gastric-intestinal

problems Decrease alertness and

ability to memorize Nervousness, pupil

dilation Decrease in the visual

field

Long term Insomnia Nervousness Bulimia chronically high blood

pressure Anxiety Depression Sexual dysfunction

Noise Pollution Control Measures Road noise:

Use of noise barriers, limitations on vehicle speed

newer roadway surface technologies

traffic control limiting times for heavy duty

vehicles Air line Noise:

Developing quieter jet engines

controlling take off and landing times

Industrial Noise: New technologies Instillations of noise barriers

in the work place Residential Noise:

Regulate noise from power tools, garden equipement, loud radios

Relevant Law

Noise Pollution Control Act (1972): Establishes a national policy to promote an

environment free from noise that jeopardizes health

Establishes a means for the coordination of federal research activities in noise control

Authorizes establishment of federal noise standards and products

Provides information to the public respecting noise emission and noise reduction characteristics of such protocol