Outdoor air can contain pollutants. These pollutants can be the result of human activity (car exhaust or trash burning, for example) or from natural sources (such as pollen or radon). Air pollution has been linked to specific health problems, such as asthma, heart disease and lung cancer.
Overall, Vermont's air quality is good. Vermont has much less traffic congestion, commerce and industry that can contribute to poor air quality. Even so, there are days when high levels of fine particulate matter in the air make it risky to be outdoors and physically active, especially older adults, children, and people with chronic conditions such as asthma.
In Vermont, these higher risk days are often during periods of hot, humid weather. Particulates can aggravate existing heart and lung diseases, lower the body's defenses against inhaled materials, and damage lung tissue.
Under the Clean Air Act of 1970, the U.S. Environmental Protection Agency (EPA) began to set limits or standards on how much of a pollutant can be in the air anywhere in the United States. The goal of these limits is to help ensure that all Americans have the same basic health and environmental protections.
EPA established standards for six criteria pollutants: carbon monoxide, lead, nitrogen dioxide, sulfur dioxide, ozone and particulate matter. These standards, called the National Ambient Air Quality Standards (NAAQS), help protect public health and the environment.
The Centers for Disease Control and Prevention works closely with the EPA to publish air quality data on the National Tracking Network and to help better understand how air pollution affects our health.
Each state develops its own plan on how to monitor air under the Clean Air Act. The Vermont Department of Environmental Conservation (DEC) maintains an air quality monitoring program to measure ozone, nitrogen oxides, carbon monoxide, particulate matter, sulfur dioxide and toxic elements. Air pollution is monitored at stations in Underhill, Burlington, Rutland and Bennington.
DEC provides an Air Quality Index (AQI) with hourly updates from the four monitoring sites at http://www.anr.state.vt.us/air/Monitoring/cfm/RealTimeData.cfm