Ch. 16 Air Pollution

Acid Deposition/Acid Precipitation:

Acid precipitation-deposition of wet acidic solutions or dry acidic particles from the air. Unpolluted rain generally has pH of 5.6. Carbonic acid from atmospheric CO2. H2SO4 and HNO3 from industrial and automobile emissions are cause of acid precipitation. Aquatic effects are severe, as pH of 5 in freshwater lakes disrupts animal reproduction and kills plants, insects and invertebrates. Below pH5, adult fish die.

Air Pollution Trends in the U.S.

Air pollution in the US has improved dramatically in the last decade. The only pollutants that have not shown significant declines are particulates and Nitrogen Oxides. 80% of US cities now meet National Ambient Air Quality Standards.

EPA Method Nine: Opacity

Background blocking ability from emissions such as smoke. Requires certified "smoke" readers to determine compliance with Air Quality Act and Rules. Every 6 months, certified readers must pass a Method 9 EPA certified school. Such tests include successfully passing 50 readings, various opacities, of white and black smoke.

Hazardous Air Pollutants (HAP)

Can cause cancer and nerve damage. Require special reporting and management as they remain in ecosystems for a long period of time, and tend to accumulate in animal tissues. Include carcinogens, neurotoxins, endocrine disrupters.

Cap and Trade

Cap and Trade programs, begun in 1990, set maximum amounts for pollutants, but let facilities facing costly cleanups pay others with lower costs to reduce emissions on their behalf. Has worked well for sulfur dioxide. However, it permits local hot spots where high polluters continue to pollute because they are paying someone somewhere else to reduce pollution.

Chlorofluorocarbons (CFCs)

Chemical compounds with a carbon skeleton and one or more attached chlorine and fluorine atoms. Commonly used as refrigerants, solvents, fire retardants, and blowing agents.

Stratospheric Ozone Depletion

Discovered in 1985 that stratospheric ozone levels over South Pole were dropping rapidly during September and October. Occurring since at least 1960. Chlorofluorocarbons (CFC) are the cause. At ground-level, ozone is a pollutant, but in the stratosphere it screens UV radiation. A 1% decrease in ozone could result in a million extra human skin cancers per year worldwide. Decreased agricultural production and reduced plankton in the ocean , the basis of food chain.

EPA Method Nine: Opacity continued-

Generally, opacities greater than 40% are violations of Georgia Air Quality Control Act and Rules. Some industries have language in their Air Quality permits no more than 20% opacity.

Effects of Air Pollution

Human Health-who estimates each year 5-6 million people die prematurely from illnesses related to air pollution. Likelihood of suffering ill health is related to intensity and duration of exposure. As much as a 5 to 10 year decrease in life expectancy if you live in worst parts of Los Angeles.

Particulate Matter continued:

Human health suffers from exposure. Cities with high particulates have a higher death rate. Dust also carries bacteria, viruses, fungi, pesticides, herbicides and heavy metals. Outbreak of foot-and-mouth disease in Britain linked to dust from North Africa. Recent discovery of nanobacteria in dust. Primary source of allergies and asthma.

Air Pollution in Developing Countries

In developing Asia, Africa and the Americas government intervention may be weak and regulations nonexistent. Mexico City: Pollution levels exceed WHO health standards 350 days per year. More than half of children have lead levels high enough to lower intelligence. China's 400,000 factories have no air pollution controls. Former Soviet Union has serious problems as well.

Chronic Obstructive Lung Disease

Irreversible damage to the linings of the lungs caused by irritants.

Ambient Air

Is the air around us. 147 million metric tons of air pollutants are released annually into the atmosphere in the U.S. Worldwide emissions total around 2 billion metric tons. Developed countries have been improving air quality, while air quality in developing world is getting worse. 16 of the 20 smoggiest cities in the world are in China.

Unconventional Pollutants: Aesthetic Degradation

Noise, odor, light pollution. Reduce quality of life by increasing stress. Light pollution: prevents us from seeing stars (this is a serious problem for astronomers). Can confuse birds (black smoke).

Effects of Air Pollution continued:

PM 2.5 particulates less than 2.5 micron in diameter are particularly risky and have been linked with heart attack, asthma, lung cancer and abnormal fetal development. New rules will remove particulates from diesel engines and power plants. Most air pollutants are inhaled, but some can be directly absorbed through the skin or ingested in food and water.

Photochemical Oxidants

Products of secondary atmospheric reactions. Smog- the term used to describe the combination of smoke and fog in the stagnant air of London; now often applied to photochemical pollution or urban air pollution of any kind.

Air Pollution Control

Reducing Production: Conservation by reducing electricity consumption, insulating buildings and providing energy saving public transportation. Particulate Removal: Remove particles physically by trapping them in porous mesh which allows air to pass through but holds back solids. Electrostatic Precipitators: fly ash particles pick up electrostatic charge as they pass between large electrodes in waste stream, and accumulate on collecting plate.

Air Pollution Control continued:

Sulfur Removal: Switch from soft coal with a high sulfur content to low sulfur coal. Change to another fuel (natural gas). Nitrogen Oxides: Best method is to prevent creation; Staged Burners, Selective Catalysts. Hydrocarbon Control: Use closed systems to prevent escape of fugitive emissions.

Some other Conventional Pollutants

Volatile Organic Compounds (VOCs). Organic chemicals- Generally oxidized to CO and CO2. Plants are largest source. 400 million tones of methane produced by natural wetlands and rice paddies.

Synergistic Effects

When an injury caused by exposure to two environmental factors together is greater than the sum of exposure to each factor individually.

Plants are Susceptible to Pollution

Chemical pollutants can directly damage plants or can cause indirect damage by reducing yields. Certain environmental factors have Synergistic effects in which the injury caused by the combination is more than the sum of the individual exposures. Pollutant levels too low to cause visible effects may still be damaging. Ex: soybean leaves damaged by sulfur dioxide.

Ozone Hole Over Antarctic/ Stratospheric Ozone

Circumpolar vortex isolates Antarctic air and allows stratospheric temperatures to drop and create ice crystals at high altitudes. Absorb ozone and chlorine molecules. When sun returns in the spring, energy liberates the chlorine allowing it to destroy ozone. Persists for years. Hole has begun to form over Arctic, too.

Clean Air Legislation

Clean Air Act (1963)- First national air pollution control. Clean Air Act (1970) (extensively revised over time). Identified critical pollutants. Established ambient air quality standards. 1990 amendments addressed: Acid rain, Urban air pollution, toxic emissions, Ozone depletion.

Mercury

Dangerous neurotoxin, 75% of human exposure comes from eating fish. In 2007, all sampled rivers in 12 western states were contaminated. 45 states have warnings about local fish and pregnant women and children should limit consumption of tuna, swordfish, marlin, lobster. 300,000 to 600,000 children in US exposed in the womb each year, resulting in diminished intelligence. Minamata, Japan disaster.

Indoor Air Pollution: EPA

EPA found indoor concentrations of toxic air pollutants are often higher than outdoor. People generally spend more time indoors. Chloroform, benzene and other chemicals in carpeting and paints in homes can be found at concentrations that would be illegal in the workplace. Less Developed Countries also suffer from indoor air pollution. Organic fuels make up majority of household energy. These are often burned in smoky, poorly ventilated heating and cooking fires.

Long-Range Transport

Fine aerosols can be carried great distances by the wind. A 3km toxic cloud covers India for most of year, causing 2 million deaths/yr. This cloud may also be disrupting monsoon rains on which harvests in south Asia depend. Increasingly, monitoring activity has begun to reveal industrial contaminants in places usually considered among the cleanest in the world (e.g. Antarctica). Grasshopper transport- volatile compounds evaporate from warm areas; travel to poles where they condense and precipitate. Contaminants bioaccumulate in food webs. Whales, polar bears, sharks have dangerously high levels of contaminants (such as HAP).

Acid Deposition continued:

Forest Damage: Air pollution and depositions of atmospheric acids are believed to be important causes of catastrophic forest destruction in Europe, North America. Buildings and Monuments: Limestone and marble are destroyed by air pollution at an alarming rate. Corroding steel in reinforced concrete weakens buildings, roads, and bridges. Smog and Haze reduce visibility.

Human Health Effects : Bronchitis

Persistent inflammation of airways in the lung that causes mucus build-up and muscle spasms constricting airways. Can lead to emphysema-irreversible chronic obstructive lung disease in which airways become permanently constricted and alveoli are damaged or destroyed. In the U.S. half of all lungs examined at autopsy show alveolar deterioration. Smoking is the most important air pollution in the U.S. 400,000 die annually from diseases related to smoking. This is 20% of all mortality. Associated costs are estimated at $100 billion annually.

Anthropogenic Air Pollution/Primary Pollutants

Primary Pollutants-released directly from the source, from air stacks already harmful. Primary standards-intended to protect human health. Secondary Pollutants-converted to a hazardous form after entering the air and mixing with other air components; not hazardous coming out, but becomes hazardous. Fugitive Emissions-do not go through smokestack. Dust from strip mining, rock crushing, building construction/destruction. Secondary Standards-to protect other things.

Toxic Release Inventory (TRI)

Requires manufacturers to report on toxin release and waste management. Most HAP are decreasing but mercury and dioxins (from plastics) are increasing. More than 100 million Americans live in areas where cancer rate is 10x normal standard.

Dust Storms

Soil erosion causes dust and sand storms that put particulate matter into air. Dust can travel thousands of km. Dust from the Sahara regularly ends up in Miami, Florida. Some benefits to this movement of particulate matter, as nutrients from Africa fertilize the Amazon basin.

Aerosols

Solid particles or liquid droplets suspended in the atmosphere. Atmospheric aerosols are usually called particulate material. Includes ash, soot, lint, smoke, pollen, spores, etc. Aerosols reduce visibility. When smaller than 2.5 micrometers, they enter lungs and cause damage. Asbestos and cigarette smoke cause cancer. Larger than 2.5 micrometer not as likely to enter the lungs. PM10 filters: Examples include fugitive dust from roadways.

Clean Air Legislation continued:

Source review in 1977 allowed old plants to be grandfathered in, but required new equipment to meet air pollution standards. Result was that companies kept old facilities operating in order to avoid pollution controls. Thirty years later, these old plants (often expanded in size) continue to be among biggest contributors to smog/acid rain. Despite disputes, has been successful in saving money and lives.

Signs of Progress

Sweden and West Germany cut their sulfur emissions by two-thirds between 1970 and 1985. Australia and Switzerland even regulate motorcycle emissions. Delhi, India was once one of world's most polluted cities. According to health experts, breathing the air was equal to smoking 2 packs of cigarettes a day. After instituting air pollution controls, the air is dramatically cleaner with sulfur dioxide levels reduced 80% and carbon monoxide levels down 70%.

Climate and topography: Inversions

Temperature inversions occur when a stable layer of warm air lies above cooler air, reversing the normal temperature decline with increasing height, and prevents convection currents from dispersing pollutants. Rapid nighttime cooling in a basin as the cold air becomes trapped.

Criteria Pollutants, Six Major air pollutants know forms, sources, (natural & manmade) detrimental effects.

1. Sulfur Dioxide-Natural sources, Evaporation of Sea Spray, detrimental effects-acid rain. 2. Nitrogen Oxides-reactive gases formed when nitrogen is heated above 650 degrees C in the presence of oxygen, or when nitrogen compounds are oxidized by bacteria. Causes eutrophication of inland waters and coastal seas. Growth of weeds that crowd out native species. Humans responsible for 60% emissions. 3. Carbon Monoxide-Colorless, odorless, toxic gas produced by incomplete fuel combustion, cars & trucks. Inhibits respiration by binding irreversibly to hemoglobin in the blood. One contributing factor to global warming. 4. Ozone-Layer in the stratosphere shields the biosphere by absorbing incoming uv radiation. In the troposphere it is a pollutant- a photochemical oxidant (product of secondary atmospheric reactions driven by solar energy). Has an acrid, biting odor that is a characteristic photochemical smog. Damages vegetation and buildings. 5. Lead-Many toxic metals occur as trace elements in fuel, especially coal. Lead is 2/3 of all metallic air pollution. Lead is a neurotoxin. Banning lead from gas was one the most successful pollution controls in American history. Since ban, children's average blood levels have dropped 90% and average IQ has risen 3 points. 6. Particulate Matter-Aerosol: solid particles or liquid droplets suspended in the atmosphere. Atmospheric aerosols are usually called particulate material. Includes ash, soot, lint, smoke, pollen, spores, etc. Aerosols reduce visibility when smaller than 2.5 micrometers, they enter lungs and cause damage. Asbestos and cigarette smoke cause cancer. Larger than 2.5 micrometers not likely to enter lungs. PM 10 filters, Examples include fugitive dust from roadways and emissions, road dust.

Natural Sources of Air Pollution

1. Volcanoes-Ash and acidic components 2. Sea Spray-Sulfur compounds 3. Vegetation-Volatile organic compounds 4. Dust storms 5. Bacteria metabolism is responsible for 2/3 of methane in the air.

EPA Method Nine: Field Test Example-

50 readings - 25 white smoke, 25 black smoke. An error of three is acceptable. Four errors is a fail, must repeat the entire set reading 50. Total error of less than 38 on each set or its a fail.

Air Curtain Destructor: A Machine-

Georgia counties (greater than symbol) 65,000 populations, Air Quality Rules don't allow open burning of land -clearing debris. Glynn county has at least 75,000 population. In counties where open burning is allowed, no closer than 1,000 feet from a dwelling. Air curtain destructors, when allowed, may burn controlled burn within 300 degrees of a dwelling. Once air curtain destructor begins operations, opacities must be less than 40%.

Montreal Protocol

Most effective International Environmental agreement ever established. Montreal Protocol (1987) phased out use of CFCs. HCFCs were substituted, which release less chlorine. Very successful - CFCs cut by 95% since 1988. Levels should be back to normal by 2049. Also contributing to the reduction of greenhouse gas emissions.