Coal Remains Pittsburgh's Top Pollutant

In my previous post, I noted that Pittsburgh has the 6th worst air pollution in the US and scores a failing grade for ozone. Whenever I mention Pittsburgh's poor air quality to anyone, the first question they ask is "Why?" I was surprised to find that as in the past, our current top polluter is coal. Specifically, coal-fired power plants, which we will discuss at length below. 

Types of Air Pollution

According to the Breathe Project, there are three main categories for air pollution in our region: 

• Ground-level ozone
• Particle pollution
• Air toxics

Ozone: Ozone, or smog, is a gas formed when oxides of nitrogen and volatile organic compounds react chemically with heat and sunlight. The precursors to ozone are emitted by sources such as power plants, coke and steel making plants, refineries, chemical plants, motor vehicles, and others. This "bad" ozone should not be confused with the "good" ozone in the stratosphere.

Source: EPA

Particulate matter: Particulate pollution is a mixture of solid particles and liquid droplets found in the air. Some particles such as dust, dirt, soot, and smoke can be seen with the naked eye. Smaller particles can only be detected with an electron microscope. Sources of particulate matter include construction sites, unpaved roads, smokestacks, fires, power plants, and motor vehicles. The figure below illustrates the size of particulate matter.

Air toxics: These are hazardous air pollutants that can cause cancer, reproductive effects, and birth defects, among other health issues. Examples include benzene (found in gasoline), perchloroethylene (used in some dry cleaning), and heavy metals (emitted by coal-fired power plants).

Our Region's Coal Problem

The Sierra Club reports that the state's 31 coal-fired power plants are the single largest source of pollution in a 10-county region of southwestern Pennsylvania. Specifically, 64% of the particulate matter in this region results from electrical generation. No other single source contributes more than 10% of the total. 

Coal-fired units produce electricity by burning coal in a boiler to heat water to produce steam. At tremendous pressure, the steam flows into a turbine, which spins a generator to produce electricity. 

Source: Tennessee Valley Authority

Coal-burning power plants release millions of pounds of toxic pollutants into the air every year. Notably, they emit 84 of the 187 hazardous air pollutants identified by the Environmental Protection Agency (EPA) as posing a threat to human health and the environment including:

• Dioxins
• Metals such as mercury, arsenic, chromium, lead, nickel, and cadmium
• Formaldyhyde
• Polycyclic aromatic hydrocarbons
• Volatile organic compounds including benzene, tolulene, and xylene
• Acid gases such as hydrogen chloride, and hydrogen fluoride
• Small amounts of radioactive materials such as radium, thorium, and uranium
• Sulfur dioxide and nitrogen oxides, which react with precipitation to form acid rain

Southwestern Pennsylvania's Biggest Polluters

The Pittsburgh Business Times lists the following plants as the top 10 air polluters in our region:

• US Steel Clairton Works, Clairton
• NRG Energy, Cheswick
• US Steel Edgar Thomson Works, Braddock
• US Steel Irvin Works, West Mifflin
• Shenango, Inc,, Neville Island
• Guardian Industries, Jefferson Hills
• Allegheny Ludlum, Brackenridge
• Allegheny Energy Supply, Springdale
• Bay Valley Foods, Pittsburgh
• Allied Waste Systems, Imperial

The Breathe Project features an online map of polluters on its website. Beneath is a screenshot of the map, featuring US Steel's Edgar Thomson plant, which is just a few miles from my house. Click here to see which plants are near you or to get more information about the industries and pollutants.

Geography

Even if you don't live close to a plant, your air quality is still affected. While people living near large sources of pollution are at particular risk, the problem is not confined to these areas. Nine out of 10 of the air quality monitors in Allegheny County rank in the worst third in the nation for particle pollution. Six out of 10 fall among the worst 10% in the country. According to Harvard environmental epidemiology professor Joel Schwartz, southwestern Pennsylvania is in an "unfortunate position" because it produces considerable industrial pollution, is downwind from industrial and utility plants in Ohio that produce pollutants, and has hills and valleys that trap bad air. 

The Good News/Looking Ahead

There is some good news for Pittsburgh residents. While our air quality is bad, the amount of fine particulate matter in our air is improving and is the lowest it has been since 2000. This is due in part to some plants switching from coal to natural gas. More clean burning diesel engines help too. The government is also fighting to impose stricter regulations on these plants, which is being met with opposition. These regulations and the fight against them will be the next topic in the Pittsburgh Smog Blog.