Ozone how does it form

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Please click here to see any active alerts. Learn more about ground-level ozone. Ozone is a gas composed of three atoms of oxygen. Ozone occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found.

Called stratospheric ozone, good ozone occurs naturally in the upper atmosphere, where it forms a protective layer that shields us from the sun's harmful ultraviolet rays. This beneficial ozone has been partially destroyed by manmade chemicals, causing what is sometimes called a "hole in the ozone. We can all take actions to help protect ourselves and reduce the damaging effects of this pollutant on our health and environment. Mary Peyton Wall , Manager, Skip to main content.

Close this alert. Taken from A. Vegetation's sensitivity to ozone varies -- not only between species, but also within a species. For example, there may be two black cherry trees growing next to one another, and one will have severe ozone symptoms while the adjacent black cherry has no visible symptoms. An example of the variation between species can be seen when an analysis is conducted with Ozone Calculator. In , Shining Rock Wilderness had a W value of Using these values as inputs, the estimated growth loss for one black cherry study was Assuming there were adequate nutrients and soil moisture, the predicted growth losses indicated that black cherry is more sensitive to ozone than red maple, which is more sensitive than sugar maple.

Berry, C. Differences in concentrations of surface oxident between valley and mountain conditions in the Southern Appalachians. JAPCA 15 6 : Hogsett, W. Growth response of two varieties of slash pine seedlings to chronic ozone exposures. Botany Lefohn, A. Musselman, R. Significance of pollutant concentration distribution in the response of 'red kidney' beans to ozone. Response of beans to simulated ambient and uniform ozone distribution with equal peak concentrations.

Skip to main content. Average ozone concentrations for each hour of the day April through October for a low elevation top and high elevation bottom sites. The low elevation site has a diurnal pattern in the ozone exposure and also shows that at lower elevations the ozone exposures are less than the ozone exposures found at high elevations. Results were produced using the Ozone Calculator. Ozone Exposure Indices for Vegetation W The W exposure index does not utilize a threshold value, but weights differentially all hourly average concentrations.

Please click here to see any active alerts. Ozone O3 is a highly reactive gas composed of three oxygen atoms. It is both a natural and a man-made product that occurs in the Earth's upper atmosphere the stratosphere and lower atmosphere the troposphere. Depending on where it is in the atmosphere, ozone affects life on Earth in either good or bad ways.

Stratospheric ozone is formed naturally through the interaction of solar ultraviolet UV radiation with molecular oxygen O2. The "ozone layer," approximately 6 through 30 miles above the Earth's surface, reduces the amount of harmful UV radiation reaching the Earth's surface. Tropospheric or ground-level ozone — what we breathe — is formed primarily from photochemical reactions between two major classes of air pollutants, volatile organic compounds VOC and nitrogen oxides NOx.

These reactions have traditionally been viewed as depending upon the presence of heat and sunlight, resulting in higher ambient ozone concentrations in summer months. Within the last decade, however, high ozone concentrations have also been observed under specific circumstances in cold months, where a few high elevation areas in the Western U.

Ozone contributes to what we typically experience as "smog" or haze, which still occurs most frequently in the summertime, but can occur throughout the year in some southern and mountain regions.