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  2. Photochemical smog - Wikipedia

    en.wikipedia.org/wiki/Smog

    Photochemical smog, as found for example in Los Angeles, is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes. These pollutants react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

  3. Ground-level ozone - Wikipedia

    en.wikipedia.org/wiki/Ground-level_ozone

    Ground-level ozone is both naturally occurring and anthropogenically formed. It is the primary constituent of urban smog, forming naturally as a secondary pollutant through photochemical reactions involving nitrogen oxides and volatile organic compounds in the presence of bright sunshine with high temperatures. [35]

  4. Peroxyacyl nitrates - Wikipedia

    en.wikipedia.org/wiki/Peroxyacyl_nitrates

    In organic chemistry, peroxyacyl nitrates (also known as Acyl peroxy nitrates, APN or PANs) are powerful respiratory and eye irritants present in photochemical smog. They are nitrates produced in the thermal equilibrium between organic peroxy radicals by the gas -phase oxidation of a variety of volatile organic compounds (VOCs), or by aldehydes ...

  5. Peroxyacetyl nitrate - Wikipedia

    en.wikipedia.org/wiki/Peroxyacetyl_nitrate

    It is a secondary pollutant present in photochemical smog. [1] It is thermally unstable and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas. [2] It is a lachrymatory substance, meaning that it irritates the lungs and eyes. [3] Peroxyacetyl nitrate, or PAN, is an oxidant that is more stable than ozone. Hence, it is more capable ...

  6. NOx - Wikipedia

    en.wikipedia.org/wiki/NOx

    When NO x and volatile organic compounds (VOCs) react in the presence of sunlight, they form photochemical smog, a significant form of air pollution.The presence of photochemical smog increases during the summer when the incident solar radiation is higher.

  7. Air pollution - Wikipedia

    en.wikipedia.org/wiki/Air_pollution

    Peroxyacetyl nitrate (C 2 H 3 NO 5): formed from NO x and VOCs, like ozone. Photochemical smog: particles are formed from gaseous primary contaminants and chemicals. [95] Smog is a type of pollution that occurs in the atmosphere. Smog is caused by a huge volume of coal being burned in a certain region, resulting in a mixture of smoke and sulfur ...

  8. Ozone - Wikipedia

    en.wikipedia.org/wiki/Ozone

    Ozone (/ ˈ oʊ z oʊ n /) (or trioxygen) is an inorganic molecule with the chemical formula O 3.It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope O

  9. Photoinitiator - Wikipedia

    en.wikipedia.org/wiki/Photoinitiator

    NO 2 in the troposphere gives smog its brown coloration and catalyzes production of toxic ground-level ozone (O 3). Molecular oxygen ( O 2 ) also serves as a photoinitiator in the stratosphere, breaking down into atomic oxygen and combining with O 2 in order to form the ozone in the ozone layer.