Air Pollution

Chapter 15

PARTICULATES

• Soot, dust, asbestos, pollen.• PM – 10 is particulate matter 10 (¼) the

diameter of a human hair.

Mixed species pollen

Quick review

Coriolis effect

• As the earth spins on its axis the equator spins faster than the poles. Heated air rises from the equator and is deflected east and west over different parts of the planet

Global Warming and Global Cooling Are Not New (1)

– What are some natural events that can alter climate?

Volcanic emissions• Changes in solar input• Movement of the continents• Impacts by meteors

• Over the past 900,000 years– Glacial and interglacial periods

Sources and Types of Air Pollutants

A weather cell is prevailing belts of wind that distribute air and moisture

Case Study: Lead Is a Highly Toxic Pollutant (2)

• Reduction of lead (Pb)– Unleaded gasoline– Unleaded paint

• Still problems– 2007: toys with Pb paint recalled– Global ban on lead in gasoline and paint

Sunlight Plus Cars Equals Photochemical Smog

• Photochemical Smog-primary and secondary pollutants reacting with UV radiation from the sun– Chemical composition of ground level photochemical smog is OZONE– Causes: exhaust from commuter traffic.

• VOCs + NO2 + Heat + Sunlight yields >>>>> the below– Ground level O3 and other photochemical oxidants– Aldehydes– Other secondary pollutants

• Human health and environmental impact >>>irritate to eyes and lungs. Effects older folks and infants more adveresly.

Global Warming Is a Major Threat to Biodiversity (1)

• Most susceptible ecosystems– Coral reefs What is coral bleaching?– Polar seas– Coastal wetland– High-elevation mountaintops– Alpine and arctic tundra

Global Outlook: Photochemical Smog in Santiago, Chile

Case Study: Air Pollution in the Past: The Bad Old Days

• United States – 1948: Donora, PA; first U.S. air pollution disaster– 1963: New York City

Why would air pollution from the burning of coal be worse in the winter?

SHORT HISTORY OF AIR POLLUTION IN LONDON

• https://www.youtube.com/watch?v=SXGakIQSOn0

Urban Heat Island Effect

• The main cause of the urban heat island is the build up of heat in road and building materials which is then released at night. The effect is more common in the winter and summer. WHY?

Urban heat island effectATLANTA GA.

A Temperature Inversion- a layer of warm air can lie atop a layer of cooler air. The layer of cooler air is more dense

and thus does not rise and mix with the air above it

Air pollution

Gases• CO CO2

• Sulfur dioxide SO2 and Sulfuric Acid H2SO4

• Ozone

• Radon (gas Rn)

• VOC (Volatile organic compound)

CommentsCombustion of gasoline, oil, wood,

volcano

Produced by burning of high and low sulfur content coal. ACID RAIN

BAD in the troposphere caused by a photochemical reaction.

May enter homes through the foundations. Lung cancer

Methane, tannins, benzene

Air Pollution Essential Formula’s

• 4 Fe S2 + 11 02 > 2 Fe2O3 + 8 SO2 Burning of

coal forms SO2 a primary pollutant

Review of pH scale

ACID RAIN

• 2 SO2+ + O2 > 2 SO3 (SO3 is a secondary pollutant)

SO3 = H2O > H2SO4 (sulfuric acid/ acid rain)

Sulfuric acid is also a secondary air pollutant

PHOTOCHEMICAL SMOG

• N2 + 02 with combustion > 2NO

Then NO2 >sunlight> > NO + O

Then O + O2 > O3

A ground level pollutant in the troposphere

ACID DEPOSITION

• RAIN, SNOW, FOG, CLOUD VAPOR WITH A pH of less than 5.6

• Some soils have calcium carbonate which acts as a buffer. Some lakes are acidic because the soil surrounding the body of water is acidic.

Acid Disposition Is a Serious Regional Air Pollution Problem

• Acid deposition, acid rain– Formation– Local versus regional problems– Effects of prevailing winds– Buffers Calcium Carbonate– Where is the worst acid deposition? Slide

Current and Possible Future Acid Rain Problem Areas

Leaching low pH rainfall can result in mercury and lead leaching from rocks into bodies of water.

Graph of pH tolerances of some aquatic organisms.

Note: the young of all organisms are more affected by shifts in pH.

Electrostatic Precipitator

Electrostatic Precipitator

• They work better than paper filtration and are easy to maintain. However, they use large amounts of electricity and produce dust that must be disposed safely. When compared to wet scrubbers, they remove particles such as soot more effectively.

Wet scrubbers

• Using calcium carbonate to remove sulfur dioxide emissions. Wet scrubbers work best in removing gasses.

Good news- The Clean Air Act and it amendents (1970/ 77/93)

What is the Clean Air Act?

• The Clean Air Act is the federal law designed to make sure that all Americans have air that is safe to breath. Public health protection is the primary goal, though the law also seeks to protect our environment from damage caused by air pollution.

When was the Clean Air Act passed?

• Congress passed the core provisions of the Clean Air Act in 1970. The law was amended in 1977 and again in 1990 to extend deadlines but also to specify new strategies for cleaning up the air. The basic framework of the law and its public health objective have remained intact.

How does the Clean Air Act work?

• The Clean Air Act requires that the U.S. Environmental Protection Agency set national health-based air quality standards to protect against common pollutants including ozone (smog), carbon monoxide, sulfur dioxide, nitrogen dioxide, lead, and particulate soot. State governments must devise cleanup plans to meet the heath standards by a specific date. (Areas with the worst smog have a longer time to meet the standards.) In addition, the EPA sets national standards for major new sources of pollution including automobiles, trucks and electric power plants. The agency also is charged with developing controls for major sources of such toxic pollutants as benzene.

• Leaded gasoline will no longer be available in the United States after December 31, 1995.

The Clean Air Act Amendments of 1990 mandate the elimination of lead from all U.S. motor fuel by January 1, 1996. Thisrepresents the final step in a gradual reduction of lead in gasoline since the early 1970s. "Regular" gasoline typicallycontained approximately 4.0 grams of lead per gallon; average lead content was reduced to 0.5 gram/gallon in 1985, andstill further to 0.1 gram/gallon in 1986.

"Unleaded gasoline" is allowed to contain no more than 5/100ths of a gram of lead per gallon.

CAFÉ’ STANDARDSCorporate Average Fuel Economy

• First enacted by Congress in 1975, the purpose of CAFE is to reduce energy consumption by increasing the fuel economy of cars and light trucks. NHTSA has recently set standards to increase CAFE levels rapidly over the next several years, which will improve our nation’s energy security and save consumers money at the pump. This site contains an immense amount of information about the CAFE program including a CAFE overview, rulemaking actions, fleet characteristics data, compliance activities, summaries of manufacturers’ fuel economy performances since 1978, and related studies.