Recently in western Pennsylvania, there has been a lot of discussion about air quality, pollution, and the importance of protecting your lungs when you are considered part of a “sensitive” population. However, the terminology and classification may be confusing. What does it mean to be “sensitive” to dips in air quality, and how would someone know that they need to protect their lungs?

The Clean Air Act is a law that mandates that the Environmental Protection Agency’s (EPA) Office of Air Quality Planning and Standards (OAQPS) set national ambient air quality standards (NAAQS). These standards evaluate pollutants that are considered harmful to people and the environment, and include six criteria:
• Ground-level ozone
• Particulate matter
• Carbon monoxide
• Lead
• Sulfur dioxide
• Nitrogen dioxide

In order to communicate these pollutant levels to the public, the EPA has established an Air Quality Index (AQI), which quantifies local air quality levels using five of the six pollutants previously mentioned (lead is excluded). The AQI ranges from 0-500, and is color-coded for ease of communication to the public. The AQI alerts individuals about when they should take actions to protect their lungs.

Some individuals are considered to be part of “sensitive populations.” This terminology means that it would be harder for an individual to protect themselves—and recover from—dips in air quality. The elderly, children, individuals with lung disease, and individuals with heart disease are included in this classification. Therefore, when pollutant levels rise, they tend to feel the effects before the rest of the population does.

It is important for individuals from sensitive populations to be aware of the air quality levels in their community, so that they may take steps to protect their lungs. You may register online at for daily AQI email alerts, or visit to review current air quality levels.

Exposure to pollutants can reduce the ability for the lungs to function normally. This is particularly true for sensitive groups. To protect your lungs when the AQI level is high, reduce the amount of time you spend outdoors, and limit your exertion levels outdoors. For more information on the Clean Air Act, visit

1. Environmental Protection Agency (2016). Air quality. Retrieved from
2. Environmental Protection Agency (2016). Air quality index (AQI) basics. Retrieved from