AIR POLLUTION

Pollutants VOCs=volatile organic compounds: chemicals used to manufacture and maintain building materials, interior furnishing, cleaning products and personal care products. "Volatile" means that these chemicals evaporate or can easily get into the air at room temperature. "Organic" means these chemicals are carbon based. Particulates=extremely small particles and liquid droplets, acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. Ground level ozone=created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.

More on Pollutants Carbon monoxide=colorless, odorless gas emitted from combustion processes Nitrogen oxides= NO 2 forms quickly from emissions from cars, trucks and buses, power plants, and off- road equipment. contributes to the formation of ground-level ozone, and fine particle pollution Sulfur dioxide= industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment. Lead=a metal found naturally in the environment as well as in manufactured products.

Pollutants Primary pollutants emitted directly from a source. Examples: sulfur dioxide, nitrous oxide, carbon dioxide, Secondary pollutants forms when other pollutants (primary pollutants) react in the atmosphere. Examples: ozone, NO2, which is formed as NO combines with oxygen in the air; and acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water

Acid Rain-what is it? Precipitation (including snow, fog, mist, gas, and dust). with pH less than normal

The pollutants sulfur dioxide and nitrogen oxides Combine with the precipitation to form: sulfuric acid and nitric acid. Source: volcanoes, marshes, and human activities

Deposition Dry deposition= acidic gases and particles 50 % of acidity in atmosphere Wind can blow it around Ends up in runoff Wet deposition= acidic rain, fog, and snow

The effects Acidification lakes and streams Damage to trees, plants, and soils Damage to buildings and paints

Acidification of Lakes and streams Causes aluminum to increase in water Acid and aluminum levels kill fish (acid shock) Stream diversity declines

Damage to soils If soils have limestone bedrock neutralizes acid in rain If soils do not, acid accumulates in lakes, streams, soils Nutrients leached from soils Aluminum increases in soils

Damage to trees/plants needles and leaves turn brown and fall off. stunted growth damaged bark and leaves, vulnerable to weather, disease, and insects.

Damage to buildings and paints Accelerated weathering of building stone/statues Deterioration of paints and finishes Corrosion of metals

Ozone depletion: How does it happen? certain chemicals used on earth escape into the atmosphere they are broken down by solar radiation and release chlorine and bromine atoms in a chain reaction, they destroy ozone molecules

Ozone, what depletes it? CFCs=(chlorofluorocarbons) refrigerants, aerosols, solvents, insulating foams HCFCs=(Hydrochlorofluorocarbons) insulating foams, refrigerants Halons=(agriculture, dry cleaning, fire suppression (fire extinguishers) Methyl bromide=pest control fumigant Carbon tetrachloride=fire extinguishers, pre refrigerant, cleaning agent Methyl chloroform=used as a solvent Any manufactured halogen source gases

Most common sources

EGEE Pisupati16 The Antarctic Ozone Hole The ozone hole is defined as the area having less than 220 dobson units (DU) of ozone in the overhead column (i.e., between the ground and space). dobson units Source:

SMOG Smoke + fog Primarily composed of ground level ozone Two types: industrial and photochemical Industrial= from the burning of coal and oil that contains sulfur Photochemical=automo bile exhaust, contains Nitrogen Oxides, Ozone, Alkanals, Peroxyacyl Nitrates (PANs), react in the atmosphere with sunlight to form secondary pollutants

Inversion normal decrease in air temperature with increasing altitude is reversed and air above the ground is warmer than the air below it.

Greenhouse effect Greenhouse gases: The most important greenhouse gases are: H 2 O – Water vapor. CO 2 – Carbon Dioxide CH 4 – methane What is the greenhouse effect? The retention of part of the Sun's energy in the Earth's atmosphere in th eform of heat as a result of the presence of gree nhouse gases.