Laws to Prevent and Reduce Air Pollution

Unit 4

Human Input of Pollutants into Troposphere

• Nitrogen and Sulfur compounds released by burning fossil fuels

• CO2 & other greenhouse gases from burning fossil fuels & clearing forests

Urban Air Pollution

Photochemical Smog in every CityChemical reactions triggered by light. Over 100 chemical substances i.e. O3

Acid rainThe hotter theday the more O3

Industrial Smog• consists mostly of sulfur dioxide (SO2), sulfuric acid

(H2SO4) suspended in droplets, & particulates (soot)

• sulfur compounds in coal & oil react with oxygen to form sulfur dioxide: S + O2 –> SO2

Acid rain

– Industrial smog is less common in “developed countries”, but a major problem in countries like China, India, & Russia where oil & coal are burned without sufficient pollution control.

Acid Deposition

• Acid deposition, which consists of rain, snow or gas with a pH lower than 5.6 is commonly called acid rain. Soils and lakes vary in their ability to buffer or remove excess acidity.

Acid Deposition

Effects of acid rain on Trees & Soils

Effects of acid rain on Aquatic Life

• high acidity (low pH) leaches harmful minerals such as aluminum into the environment;

• kills fish & other organisms; inhibits reproduction; disrupts food chains; & decreases productivity.

Massive plant, invertebrate, fish & bird extinctions• Norway and Sweden over 16,000 lakes are dead• Canada 14,000 lakes are affected• US over 9,000 lakes are affected

Effects air pollution on Health

• carbon monoxide (CO): reacts with hemoglobin in red blood cells & reduces ability of blood to carry oxygen;

• particulates: long–term exposure contributes to lung disease & cancer, aggravates bronchitis & asthma;

• sulfur dioxide (SO2): causes constriction of airways & can cause bronchitis;

Effects air pollution on Health

• nitrogen oxides (especially NO2): irritate lungs, cause conditions similar to bronchitis & emphysema;

• volatile organics (& toxic particulates): cause mutations, reproductive problems, & cancer;

• ozone: causes coughing, chest pain, shortness of breath, & eye, nose, & throat irritation.

Preventing & Reducing Air Pollution

Indoor Air Pollution is higher than outdoor

Clean Air Acts of 1970, 1977, & 1990

• require Environmental Protection Agency (EPA) to establish national ambient air quality standards (NAAQS);

• NAAQS apply to seven pollutants: suspended particulate matter, sulfur oxides, carbon monoxide, nitrogen oxides, ozone, volatile organic compounds, & lead;

Clean Air Acts of 1970, 1977, & 1990

• national emission standards for toxic air pollutants require the EPA to regulate many toxic air pollutants.

• prevention of significant deteriorization

Success of Clean Air Act• decrease of six of seven major pollutants;

• nitrogen dioxide levels increased slightly, primarily from automobiles;

• 1996 study by EPA shows that benefits greatly exceed costs: 1970–90 $436 billion spent, health benefits of $2.7 to $14.6 trillion;

• EPA estimates that 107 million Americans live in areas that exceed at least one outdoor air pollution standard.

National Emissions Standards for Hazardous Air Pollutants

• Identified and targeted 8 toxic pollutants– Arsenic - Coke oven emissions– Asbestos - Mercury– Benzene - Radionuclides– Beryllium - Vinyl chlorides

Clean Air Act (CAA) 1990 expanded to 188 toxic Air Pollutants

Reducing Emissions

Solutions to prevent& reduce indoor air pollution.