Unformatted text preview: secondary pollutant is peroxyacetyl nitrate, better known as PAN. PAN literally brings tears
to your eyes. It is an example of a lachrymator, a compound that causes burning of the eyes and tears. Onions,
as you know, contain a lachrymator.
Unburned hydrocarbons in automobile exhaust also produce secondary air pollutants. The oxidation of
unburned hydrocarbons produces various alcohols and organic acids. These can condense to produce an aerosol.
Aerosols are liquid droplets dispersed in air. They are objectionable because they reduce visibility and make the
air look hazy.
Efforts to control smog are usually focused on reducing the source of primary pollutants. The catalytic
converters on automobiles are designed to remove NO, CO, and unburned hydrocarbons from automobile
exhaust. The catalyst contains platinum and palladium metals. Nitrogen monoxide, a primary pollutant, is
converted back to nitrogen and oxygen by a reaction whose rate is increased by the catalyst in the converter.
2NO(g) → N 2 (g) + O 2 (g)
Carbon monoxide and unburned hydrocarbons are both oxidized to carbon dioxide by the catalytic converter,
as shown by the following equations (C5 H12 represents a typical hydrocarbon).
2CO(g) + O 2 (g) → 2CO2 (g)
C 5 H12 (g) + 8O 2 (g) → 5CO2 (g) + 6H 2 O(l) Back Forward Main Menu TOC Study Guide TOC Textbook Website MHHE Website Chemistry in the Atmosphere 3 63
15. Name three primary pollutants.
16. Name three pollutants that are removed by catalytic converters.
17. Is ozone in a city a primary or secondary pollutant? INDOOR AIR POLLUTION
2. Describe the source of radon and how it gets into buildings.
Describe why the main health effects of radon are to the lungs. Radon Gas. All isotopes of radon are radioactive. Concern about radon in homes began in 1984 when a
worker at a nuclear power plant in Pennsylvania found that he was setting off the plant's radiation monitor
alarms in the morning upon arriving at the plant. The source of the radioactivity was traced to the worker's
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