Air Quality Index

Air Quality Index

The Air Quality Index (AQI) is a numerical scale used for reporting daily air pollution levels. It provides a standardized public health advisory and is a tool for effectively communicating the risks posed by air pollution to the public.

Overview

The AQI focuses on health effects that may be experienced within a few hours or days after breathing polluted air. It uses a complex algorithm that converts pollutant concentrations in a community's air into a number on a scale of 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern.

Calculation

The AQI is calculated for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, the United States Environmental Protection Agency (EPA) has established national air quality standards to protect public health.

AQI Levels

The AQI is divided into six categories, each corresponding to a different level of health concern. The six levels are: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), and Hazardous (301-500).

Health Implications

Exposure to high levels of air pollution can lead to a number of health problems. Short-term effects can include irritation to the eyes, nose, and throat, headaches, nausea, and allergic reactions. Long-term effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys.

Monitoring and Reporting

The AQI is reported daily in many areas across the world. In the United States, the AQI is reported by the EPA and local agencies. The AQI can also be reported by private companies and is often included in local weather forecasts.

See Also

• Air pollution
• Environmental health
• Public health