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NO x reacts with volatile organic compounds in the presence of sunlight to form ozone. Ozone can cause adverse effects such as damage to lung tissue and reduction in lung function mostly in susceptible populations (children, elderly, asthmatics). Ozone can be transported by wind currents and cause health impacts far from the original sources.
Although the ozone precursors often originate in urban areas, winds can carry NOx hundreds of kilometers, causing ozone formation to occur in less populated regions as well. Methane, a VOC whose atmospheric concentration has increased tremendously during the last century, contributes to ozone formation but on a global scale rather than in local ...
One study finds significant positive associations between chronic ozone and all-cause, circulatory, and respiratory mortality with 2%, 3%, and 12% increases in risk per 10 ppb [93] and report an association (95% CI) of annual ozone and all-cause mortality with a hazard ratio of 1.02 (1.01–1.04), and with cardiovascular mortality of 1.03 (1.01 ...
The null cycle can be broken in the presence of certain molecules, leading to a net increase or decrease in ozone in the stratosphere. One important example is NO x emissions into the stratosphere. The NO x reacts with both the atomic oxygen and ozone leading to a net decrease in ozone. [2] This is particularly important at night when NO 2 ...
Peroxyacetyl nitrate, or PAN, is an oxidant that is more stable than ozone. Hence, it is more capable of long-range transport than ozone. It serves as a carrier for oxides of nitrogen (NOx) into rural regions and causes ozone formation in the global troposphere. [1]
Sulfate pollution also has a complex relationship with NOx pollution and ozone, reducing the also harmful ground-level ozone, yet capable of damaging the stratospheric ozone layer as well. [122] Stratospheric sulfates from volcanic emissions cause transient cooling; the purple line showing sustained cooling is from tropospheric sulfate pollution.
Concentrations of hazardous ground-level ozone have worsened in northern China despite country-wide efforts to tackle air pollution, according to a study published by Peking University on Tuesday.
Ozone can also form from reactions of VOCs or carbon monoxide and NOx. Exposure to higher levels of ozone during pregnancy has been linked with an increased risk of stillbirth, infant mortality, and brain disorders. [22] PM 2.5 and ozone levels are converted from scientific units (like μg m −3) to air quality index levels. The maximum AQI ...