Air quality affects how you breathe and how you live. It can change from day to day or even hour to hour. The United States Environmental Protection Agency (USEPA) and West Virginia Department of Environmental Protection (WVDEP) provide information about outdoor air quality, how unhealthy air may affect you, and how you can protect your health.
National Ambient Air Quality Standards (NAAQS) have been established for acceptable concentrations of specific pollutants in the outdoor air. These standards, set by the USEPA, apply to pollutants which have adverse effects on human health and welfare. Two standards exist for each pollutant. Primary standards are designed to protect public health, including an adequate margin of safety to protect sensitive populations such as children and the elderly. The second standards were set to protect public welfare, such as decreased visibility, damage to crops, vegetation, buildings, etc. Depending on the pollutant, exposure level, and duration, the effects of air pollution can vary greatly.
Air Quality Index
The Air Quality Index (AQI) is a tool used to report information about air quality. It tells you how clean or unhealthy the air is and what associated health effects might be a concern. The AQI is calculated for five major air pollutants regulated by the Clean Air Act: ground-level ozone (O3), particle pollution also known as particulate matter (PM10 and PM2.5), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2).
What Do Air Quality Index Values Mean?
The Air Quality Index can help you understand what local air quality means to your health. AQI values at or below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy – at first for certain sensitive groups of people and then for everyone as the AQI values increase. The AQI has six levels of values and is grouped in six levels of health concern as follows:
- Good – The AQI value is between 0 and 50. Air quality is considered satisfactory and air pollution poses little or no risk. No cautionary actions are needed.
- Moderate – The AQI is between 51 and 100. Air quality is acceptable; however, unusually sensitive people should consider limiting prolonged outdoor exertion.
- Unhealthy for Sensitive Groups – When AQI values are between 101 and 150, members of sensitive groups may experience health effects, but the general public is unlikely to be affected. For example, children and older adults who are active outdoors and people with respiratory disease are at greater risk from exposure to ozone, while people with heart disease are at greater risk from carbon monoxide.
- Unhealthy – Everyone may begin to experience health effects when AQI values are between 151 and 200. Active children and adults, and people with respiratory disease such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion.
- Very Unhealthy – AQI values between 201 and 300 trigger a health alert, meaning everyone may experience more serious health effects. Active children and adults, and people with respiratory disease such as asthma should avoid all outdoor exertion. Everyone else, especially children, should limit outdoor exertion.
- Hazardous – AQI values over 300 trigger health warnings of emergency conditions. The entire population is more likely to be affected. Everyone should avoid outdoor exertion.
Finding the Air Quality Index
The AQI is a national index so the values and colors used to show local air quality and levels of health concern are the same everywhere in the United States. Checking local air quality is as easy as checking the weather.
- AQI on the Internet – The USEPA and its federal, state, and local partners have developed the AIRNow website to provide the public with easy access to national air quality information. The WVDEP reports air quality data for cities where daily monitoring data is recorded.
- AQI via email – Sign up for EnviroFlash, a free service that will alert you via email when air quality is forecast to be a concern in your area.
- AQI in the media – Some local and national newspapers and television and radio stations provide daily reports as part of weather forecasts.