Ozone (smog)

Ozone is a colorless gas that exists naturally in the upper atmosphere where it shields the earth from the sun’s harmful ultraviolet rays. Ozone close to the earth’s surface is an air pollutant. It is formed by chemical reactions between volatile organic compounds (VOCs) and oxides of nitrogen in the presence of sunlight and elevated temperatures. The primary human sources of VOCs and nitrogen oxides are industrial and automobile emissions. Ozone can be transported hundreds of miles to remote areas of the country.

Natural Resource Effects of Ozone
Ozone is one of the most toxic air pollutants to plants. It causes considerable damage to vegetation throughout the world. Plants are generally more sensitive to ozone than humans. Many native plants in natural ecosystems are sensitive to ozone. The effects of ozone range from visible injury to the leaves and needles of deciduous trees and conifers to premature leaf loss, reduced photosynthesis, and reduced growth in sensitive plant species. Other factors, such as soil moisture, presence of other air pollutants, insects or diseases, genetics, or topographical locations can lessen or magnify the extent of ozone injury. The current state of knowledge for the Superior NF is that ozone levels are not currently high enough to cause damage to vegetation. For more information on ozone effects and monitoring, visit the following sites: