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Air Quality 102: Understanding What’s in the Air

While Pittsburgh has come a long way when it comes to air quality improvements, it still has a long way to go.

Recent research indicates that Pittsburgh has some of the worst air quality in the country. This puts Pittsburgh-area residents at risk for everything from cancer to heart attack, stroke, and various respiratory and other illnesses.

Now more than ever, we need to demand clean air—and hold polluters accountable for their actions, as well as regulators for their inaction on enforcement efforts.

At GASP, we have long believed that education is a fundamental part of advocacy. In order to effect change, we need to ensure that we are educating ourselves and our loved ones about the types of air pollution common to our area that pose a threat to our health and environment.

Of paramount concern? Criteria Air Pollutants, which are widespread pollutants that pose significant harm to people and the environment. Criteria Air Pollutants are regulated by the Environmental Protection Agency (EPA), which sets national standards for them.

They include:

Carbon Monoxide

This type of air pollution is widely known—you likely have a carbon monoxide detector in your home. Carbon monoxide is created through the burning of fuel, traffic emissions, and power plants, and its effects can be deadly. That’s because carbon monoxide reduces the amount of oxygen in your blood that can be transported to organs like the heart, lungs, and brain. Carbon monoxide is odorless, colorless and tasteless. Signs of exposure include weakness, headache, extreme fatigue, confusion, and even lack of consciousness.

Ground-Level Ozone

Ground-level ozone is a a type of air pollution emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources of chemicals that react in the presence of sunlight to form ozone. Exposure to ground-level ozone has been associated with chest pain, coughing, throat irritation, airway inflammation, reduced lung function, as well as the aggravation of respiratory conditions such as asthma, bronchitis, and emphysema.

Ground-level ozone has a distinct smell: Some describe it as somewhat metallic, while to others it is a sweet-pungent odor reminiscent of an electrical spark. To others, it has a chemical odor similar to chlorine.


Lead is emitted into the air via metals processing, waste incinerating, and the burning of leaded aviation fuel, among other things. Exposure to lead dust in the air can be detrimental to your health, causing negative impacts to your nervous, immune, cardiovascular, and reproductive systems, in addition to reduced kidney function. Lead is odorless.

Nitrogen Dioxide

Emissions from traffic and power plants cause nitrogen dioxide to be emitted into the air. Nitrogen dioxide can also be caused by the burning of fossil fuels. Exposure to nitrogen dioxide can cause airways to become irritated, and can also aggravate asthma and other respiratory illnesses. Nitrogen dioxide has a sharp, sweet smell.

Particulate Matter

Particulate matter, or PM, is the term used for a mixture of solid particles and liquid droplets found in the air. This type of air pollution is caused by myriad sources and smells like acrid smoke. Exposure to particulate matter pollution, which can smell like acrid smoke, is associated with a host of health impacts including:

  1. Increased risk of heart attack, stroke, and asthma

  2. Decreased lung function

  3. Premature birth

  4. Low birth rate

Sulfur Dioxide

Of all the air pollutants discussed, sulfur dioxide might be the most distinct in odor. You know the odor emitted when you strike a match? That’s sulfur dioxide. This type of air pollution—which is caused by fossil fuel production, as well as power plant and other industry emissions—is known to irritate airways and aggravate respiratory diseases such as asthma.

Protecting Yourself

Scary, right? Fortunately, now that you understand what types of air pollution are common in Allegheny County, you can take steps to protect yourself and your family:

  1. Check the Air Quality Index, which provides a forecast of the day’s air quality.

  2. Sign up for Allegheny Alerts, and select what type of notifications you would like to receive. These notifications can be sent via email or text. There is even an option for Allegheny County to call and leave you the information via voicemail.

  3. Pre-plan outdoor activities with air quality in mind. On days where air quality is poor, consider staying away from congested roadways and/or staying in during rush hour, when emissions are greatest.

Editor’s Note: Now that you understand more about common air pollutants and how to spot them, it’s time to arm yourself with knowledge on how to report them to the powers that be. Check out our Air Quality 101 blog here.

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