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exert a considerable impact on global warming, because it is a key air pollutant and greenhouse gas, and; impact the production of surface level ozone (contributing again to climate change). As a result, photochemical smog pollution at the earth's surface, as well as stratospheric ozone depletion, have received a lot of attention in recent years.
Low level ozone, or tropospheric ozone, is the most concerning type of ozone pollution in urban areas and is increasing in general. [60] Ozone pollution in urban areas affects denser populations, and is worsened by high populations of vehicles, which emit pollutants NO 2 and VOCs, the main contributors to problematic ozone levels. [61]
Ozone-oxygen cycle in the ozone layer. The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sydney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking ordinary oxygen molecules containing two oxygen atoms (O 2), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines ...
A 2002 study found that "Each 10 μg/m 3 elevation in fine particulate air pollution was associated with approximately a 4%, 6% and 8% increased risk of all-cause, cardiopulmonary, and lung cancer mortality, respectively."
These sections require the EPA "(1) to list widespread air pollutants that reasonably may be expected to endanger public health or welfare; (2) to issue air quality criteria for them that assess the latest available scientific information on nature and effects of ambient exposure to them; (3) to set primary NAAQS to protect human health with ...
Ozone absorbs strongly in the ultraviolet and in the stratosphere functions as a shield for the biosphere against mutagenic and other damaging effects of solar UV radiation (see ozone layer). [5] Tropospheric ozone is formed near the Earth's surface by the photochemical disintegration of nitrogen dioxide in the exhaust of automobiles. [10]
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If a gaseous emission sample is analyzed and found to contain water vapor and a pollutant concentration of say 40 ppmv, then 40 ppmv should be designated as the "wet basis" pollutant concentration. The following equation can be used to correct the measured "wet basis" concentration to a "dry basis" concentration: