The Air Quality Index (AQI) is a measure for reporting daily air quality. It indicates how polluted the air is, and what associated health effects might be a concern to different populations. An AQI is established 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 US Environmental Protection Agency (EPA) has established national air quality standards to protect public health. Please click on the first link for information on the AQI and how it is calculated on the AIR Now website. One is able to add a zip to get real time information. The AQI forecast for the Washington Metropolitan region can be found by clicking on the second link below.

For inquiries requiring the response of a DEP investigator, the requestor will typically be contacted within 3 days although resolution of the issue may take longer depending on the circumstances of the case.