On July 6 this summer, Virginia's Department of Environmental Quality issued the region's first "unhealthy" air alert since 2008. The culprit? "Bad" ozone and other air pollution that had combined to produce an abnormally high reading of 119 parts per billion in Suffolk and 70-80 parts per billion in other parts of southeastern Virginia. That compares to the natural concentration of ozone of about 10 parts per billion that was the norm more than a century ago. Ozone spikes are part of a pattern of increasing O3 levels globally, in even the most remote areas, says Dr. Jack Fishman, senior research scientist in the Science Directorate at NASA Langley Research Center in Hampton, Va.
"I think what we have to dispel is that ozone pollution is confined to places like Los Angeles and Houston," says Fishman. "Despite emission controls that have resulted in notable reductions in many American cities, O3 concentrations in non-urban areas in both the U.S. and around the world are increasing, with negative impacts to all living things -- plants, animals, and people." Fishman is an expert in the composition of the troposphere, which is the part of the atmosphere that extends from the ground up to four to 12 miles (19.3 km), depending on where it is measured. In general, the troposphere is deeper in the tropics than at higher latitudes.
The troposphere contains about 75 percent of the atmosphere's mass, 99 percent of its water vapor and is where weather occurs. Although 'good' ozone high in the stratosphere the layer just above the troposphere provides a shield to protect life on Earth, direct contact with it is harmful to plants and animals, including humans. According to the Environmental Protection Agency, exposure to ozone levels of greater than 80 parts per billion for eight hours or longer is unhealthy. Harmful effects can include throat and lung irritation or aggravation of asthma or emphysema.
"I think what we have to dispel is that ozone pollution is confined to places like Los Angeles and Houston," says Fishman. "Despite emission controls that have resulted in notable reductions in many American cities, O3 concentrations in non-urban areas in both the U.S. and around the world are increasing, with negative impacts to all living things -- plants, animals, and people." Fishman is an expert in the composition of the troposphere, which is the part of the atmosphere that extends from the ground up to four to 12 miles (19.3 km), depending on where it is measured. In general, the troposphere is deeper in the tropics than at higher latitudes.
The troposphere contains about 75 percent of the atmosphere's mass, 99 percent of its water vapor and is where weather occurs. Although 'good' ozone high in the stratosphere the layer just above the troposphere provides a shield to protect life on Earth, direct contact with it is harmful to plants and animals, including humans. According to the Environmental Protection Agency, exposure to ozone levels of greater than 80 parts per billion for eight hours or longer is unhealthy. Harmful effects can include throat and lung irritation or aggravation of asthma or emphysema.
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