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27 Dec. 2024. While the effects on climate change from burning coal for electric power produce more headlines, the impact of this energy source on human health remains a key concern at all levels. As a result, utilities generating power from coal need to install filtering devices called scrubbers, like those made by Torch-Air, to remove harmful pollutants from coal exhaust before they’re released into the atmosphere.

In 2023, coal accounted for 16 percent of all electric power generated in the U.S., according to the U.S. Energy Information Administration, with higher rates of coal power generation offshore; 60 percent in China, for example. Coal consists mainly of carbon and sulfur, and when burned, the exhaust emits the greenhouse gas carbon dioxide, sulfur dioxide or SO₂, micro- and nano-sized particulates, and other substances.

Lungs are only the beginning

We’ve known for some time that coal emissions have damaging health effects, but a 2021 review in the journal Energy Geoscience spells them out in detail.

Lungs, according to the review’s authors, “are the first target of air pollutants.” Even in low concentrations and indirect exposure, coal emissions are associated with higher rates of asthma, chronic obstructive pulmonary disease or COPD, lung cancer, and respiratory infection. But the harmful effects don’t end there. Inhaling coal emissions is also associated with damage to:

• Immune system
• Heart
• Brain
• Reproductive system
• DNA

Coal plant scrubbers

To remove SO₂ and other damaging emissions, coal-fired power plants need to install devices called scrubbers that filter and clean exhausts in the flue before reaching the outdoor air. A coal scrubber uses a chemical reaction to neutralize harmful compounds in the exhaust.

The scrubber sends out a fine mist into the flue with a water-based solution of alkaline minerals like lime or limestone. The alkaline mist absorbs the SO₂ and reacts with its ingredients to produce chemically neutral substances, such as sulfates or sulfites, that can be repurposed into gypsum for building materials. Torch-Air, in Los Angeles and Tulsa, says its wet scrubbers can remove up to 99 percent of SO₂ from coal emissions, allowing cleaner air to flow up the stack.

In power plants, coal scrubbers are used with continuous emission monitoring systems to meet stringent requirements of health and environmental authorities. Sensors monitoring the content of emissions are installed in the flue to provide real-time measurements of target contaminants. The monitoring systems then collect the sensor data and report the results to management, and eventually to authorities.

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