Catalytic Converters catalytic-converter-video.htm AIR POLLUTION REVIEW…

Catalytic Converters

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AIR POLLUTION REVIEW…

Natural air pollutants: volcanoes, fires, dust stormsPlants emit volatile organic compoundsMechanisms in the biosphere remove, assimilate, and recycle natural pollutants

Hydroxyl radical (OH): a naturally occurring compoundOxidizes many gaseous pollutants to harmless products brought to land or water by precipitation

Sea salts: a cleansing agent that helps form raindropsPicked up by wind flowing over oceans

Sunlight: breaks down organic molecules

ATMOSPHERIC CLEANSING

They also remove anthropogenic pollutants from the air

Highly reactive hydrocarbons are rapidly oxidized

Nitrogen oxides are oxidized within a day

Less reactive substances (e.g., CO) take months

Atmospheric levels of hydroxyl are determined by levels of anthropogenic air

pollutants

Hydroxyl’s cleansing power is used up

Pollutants are able to build up

Photochemical breakdown of ozone is a major source of hydroxyl radical

HYDROXYL RADICALS

THE HYDROXYL RADICAL

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