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Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. Ground-level or tropospheric ozone is created by chemical reactions between NOx gases (oxides of nitrogen produced by combustion) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone.
Ground-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 ]
Ground-level ozone and particulate matter originate from different sources and human activities such as power plants and refineries that pollute the environment around the affected area. [2] With limited dispersion and a lack of atmospheric mixing, the amount of pollutants increase and stay stagnant for days. [ 2 ]
Ground-level ozone (O 3): Ozone is created when NOx and VOCs mix. [84] Photochemical and chemical reactions involving it fuel many of the chemical activities that occur in the atmosphere during the day and night.
Triatomic oxygen (ozone, O 3) is a very reactive allotrope of oxygen that is a pale blue gas at standard temperature and pressure. Liquid and solid O 3 have a deeper blue color than ordinary O 2, and they are unstable and explosive. [5] [6] In its gas phase, ozone is destructive to materials like rubber and fabric and is damaging to lung tissue ...
NO 2 is the oxide measured and used as the indicator for the entire NO x family as it is of the most concern due to its quick formation and contribution to the formation of harmful ground level ozone. [18] In 1971 the primary and secondary NAAQS for NO 2 were both set at an annual average of 0.053 ppm. The EPA reviewed this NAAQS in 1985 and ...
In South East England, ground level ozone pollution tends to be highest in the countryside and in suburbs, while in central London and on major roads NO emissions are able to "mop up" ozone to form NO 2 and oxygen. [31]
Ventilation with outdoor air containing elevated ozone concentrations may complicate remediation attempts. [69] The WHO standard for ozone concentration is 60 μg/m 3 for long-term exposure and 100 μg/m 3 as the maximum average over an 8-hour period. [29] The EPA standard for ozone concentration is 0.07 ppm average over an 8-hour period. [70]