CLIMATE AND TOPOGRAPHY

Temperature Inversions Temperature inversions occur when a stable layer of warm

air overlays cooler air, reversing the normal temperature decline with increasing height, and preventing convection currents from dispersing pollutants.

Subsidence Inversion – large warm air mass moves into a region at a high altitude and floats over a colder air mass near the surface (preventing any vertical mixing)

Radiation Temperature Inversion – occurs at night as the air near the ground cools faster than the air above it

Inversions

ACID DEPOSITION

NATURAL ACID CO2 = carbonic acid

(carbon cycle) SO2 = sulfuric acid

(seaspray, volcanoes)

NATURAL BUFFER CaCO3 – calcium

carbonate (limestone)

TYPES Acid precipitation (rain, sleet, snow) Acid deposition (dry particles washed into soil,

aquatic ecosystems)

UN-NATURAL ACID SO2 = Coal burning

(sulfuric acid H2SO4) NO2= Automobiles

(Nitric Acid HNO)

Carbonic Acid H2CO3; Nitric Acid HNO3; Sulfuric Acid H2SO4

Acid Deposition

Acid Deposition - Impacts

Aquatic Effects - acid shock (leaching of acid and Al3+ ions from soils into water); fish do not live typically below 4.5pH

Human Impacts – respiratory (bronchitis, asthma) Damages infrastructure statues, buildings, water

pipes (can leach metals into drinking water) Leaches essential nutrients from the soil Damages primary productivity - germinating seeds

& plant tissue

Wet deposition (rain, snow, fog)/ Dry Deposition (particulates)

ACID DEPOSITION CONTROL

Wet Scrubbers - Remove SO2 by injecting limestone – forms calcium sulfate sludge

Electrostatic Precipitators - Fly ash particles (smoke & dust) pick up electrostatic charge as they pass between large electrodes in waste stream, and accumulate on collecting plate.

Alternative Energy Sources – natural gas, coal low in sulfur content (anthracite); solar; hydroelectric

Clean Air Act (1990) – mandated reduction in SO2 & NOx emissions

Clean Air Act (1963) Revision (1990) - Included provision for:

Acid Rain Urban Smog Toxic Air Pollutants Ozone Protection Marketing Pollution Rights Volatile Organic Compounds Lead

Revision (1997) - Stricter standards