Outdoor Air Quality

Current Air Quality: Visit AirNow.gov for current air quality information.

Healthy outdoor air supports a high quality of life for Montgomery County residents. With healthy air, our families, including the young and elderly, can spend more time outdoors exercising, enjoying parks and exploring the County's great neighborhoods.  

Current Air Quality

To protect human health and the environment, the Clean Air Act amendments of 1990 established standards for six air pollutants. Two of those air pollutants, ozone and particulate matter, can reach unhealthy concentrations in the Washington Metropolitan Region.

Air Quality Action Days

Air Quality Action Days occur when air pollution in the region is expected to reach unhealthy levels. They occur primarily during the summer months when hot, humid, and stagnant weather conditions contribute to the formation of air pollution.

An Introduction to Air Quality Action Days:

Health Concerns on Air Quality Action Days

Ground-level ozone is an air pollutant that damages human health, vegetation, and is a key ingredient of urban smog. Repeated exposure may cause permanent damage to the lungs and trigger a variety of health problems including chest pains, coughing, nausea, throat irritation, and congestion. Exposure can also worsen bronchitis, heart disease, emphysema, and asthma, and reduce lung capacity.

Particulate matter pollution includes dust, dirt, soot, smoke, and liquid droplets. Particulate matter can either be directly emitted into the air or formed in the atmosphere by reactions of fuel combustion gases. Inhaled particles can evade the respiratory system's natural defenses and penetrate deep into sensitive regions of the lungs. Many scientific studies have linked particulate matter to a series of significant health problems, such as aggravated asthma, chronic bronchitis, decreased lung function, and heart disease.

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