Tropospheric ozone

Ground level or tropospheric ozone is created by chemical reactions between oxides of nitrogen (NOx gases) and volatile organic compounds (VOCs). In urban areas, high ozone levels usually occur during warm summer months. Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day. Troposheric , or ground-level ozone , is the major ingredient in smog and continues to pose a health risk to many Americans.

Ground-level ozone , though less concentrated than ozone aloft, is more of a problem because of its health effects. Thus, its concentration affects how long these compounds remain in the air. These are such small amounts that they are not harmful to the health of humans, animals or the environment. Stratospheric ozone is “good” because it protects living things from ultraviolet radiation from the sun.

Satellites can measure tropospheric ozone. Measurements specifically of ground-level ozone require in situ monitoring technology. When ozone is high above the Earth in the stratosphere, it helps protect life on the ground from solar radiation by scattering incoming ultraviolet rays from the sun. However, ozone during pollution events is approximately ten times the natural level. About of total ozone in the atmosphere is in the stratosphere, and is in the troposphere.

Although tropospheric ozone is less concentrated than stratospheric ozone , it is of concern because of its health effects. These effects are to be added to the detrimental effects of other pollutants such as sulphur dioxide, nitrogen oxides,. This chapter addresses the scientific evidence that relates global change in atmospheric gases and climate to tropospheric ozone.

Such a consideration of global changes is important because they are likely to continue and might hamper local efforts to meet the ozone National Ambient Air Quality Standards (NAAQS). Shortness of breath, dry cough or pain when taking a deep breath, tightness of the chest, wheezing, and sometimes even nausea are common responses to ozone. Here, ground-level or bad ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. It is a main ingredient of urban smog.

In the troposphere, a range of chemical reactions can create ozone. At high concentrations, tropospheric ozone (O ) causes respiratory problems and is detrimental to a wide variety of plants. Ozone’s Effects on Human Health.

Photolysis of ozone leads to the formation of the hydroxyl radical (HO). However, ground-level or “bad” ozone (smog) is a biological irritant that can lead to human health problems, ecosystem damage, and crop loss. Emissions from cars, trucks, factories, and power plants are large contributors to bad ozone.

SPECIAL NOTES: All of the above data tables were determined from Nimbus TOMS (Jan79-Apr93) and Earth Probe TOMS (Aug96-Dec05) satellite measurements. Background: Tropospheric ozone is a greenhouse gas and pollutant detrimental to human health and crop and ecosystem productivity. Reading: Chapters Environmental Chemistry, G. Tropospheric ozone is formed by the interaction of sunlight, particularly ultraviolet light, with hydrocarbons and nitrogen oxides, which are emitted by automobiles, gasoline vapors, fossil fuel power plants, refineries, and certain other industries. Tropospheric ozone is also a very important absorber in the visible and infrared wavelength region and participates in the so called greenhouse-effect of the atmosphere.

This increase is responsible for ~ of the antropogenically caused greenhouse effect. Given these uncertainties, projections suggest that climate change will increase concentrations of tropospheric ozone , at least in high-income countries when precursor emissions are held constant, which would increase morbidity and mortality. Few projections are available for low- and middle-income countries. C in the Northern Hemisphere and about 0. C in the Southern Hemisphere. A novel idea of controlling the ozone concentration in the troposphere by applying ultraviolet short laser pulses is proposed.

However in the troposphere, nitrogen dioxide, not molecular oxygen, provides the primary source of the oxygen atoms required for ozone formation. The increase is nearly 0.