Sea salt contributes to air pollution primarily by releasing reactive halogens into the atmosphere, which then impact atmospheric chemistry.
Here's a breakdown of the process:
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Sea Salt Aerosols: Wave action and wind create sea spray, generating tiny particles of sea salt that become airborne. These are known as sea salt aerosols.
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Halogen Release: These aerosols contain significant amounts of halogens, such as chlorine and bromine.
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Chemical Reactions: Once in the atmosphere, these halogens undergo chemical reactions that affect other atmospheric components:
- Ozone Depletion: Halogens can participate in catalytic cycles that destroy ozone (O3), a vital component of the stratosphere that protects us from harmful UV radiation.
- Hydrocarbon Oxidation: The reactive halogens can oxidize hydrocarbons in the air. This process leads to the formation of other pollutants like ground-level ozone (smog) and particulate matter.
- Particulate Matter Formation: Some reactions lead to the formation or growth of particulate matter (PM), specifically PM10, which are inhalable particles that can cause respiratory problems.
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Contribution to PM: In coastal regions, sea salt aerosols themselves can significantly contribute to the total annual particulate matter concentration, especially PM10.
In summary, while sea salt is a natural substance, the halogens released from sea salt aerosols can react with other atmospheric components, leading to the formation of harmful pollutants, ozone depletion, and contributing to overall air pollution, especially in coastal environments.
