An April 19 CNSNews.com article by Matt Cover highlights a claim by President Obama that coal could create "the kinds of air pollution" that is "creating asthma for kids," retorting:
Asthma, however, is not caused by coal, or the emissions from coal-fired power plants, as the president suggested. According to the National Institutes of Health (NIH) the true cause of asthma is unknown, although scientists believe it is caused by a confluence of genetic and environmental factors or early viral infections.
In fact, as Media Matters details:
A 2001 study by the Harvard School of Public Health found that two coal-powered plants in Chicago were responsible for 2,800 asthma attacks per year. Likewise, the Asthma and Allergy Foundation of America states that "Substantial scientific evidence" has linked air pollutants like sulfur dioxide -- a compound released when coal is burned -- to respiratory problems. Specifically, the AAFA states that "People prone to allergy, especially those with allergic asthma, can be extremely sensitive to inhaled sulfur dioxide."
Coal-burning plants also produce nitrogen oxides. According to the Environmental Defense Fund, "Nitrogen oxides play a major role in the formation of ground-level ozone (or smog) in the summertime. Smog triggers millions of asthma attacks each year in the U.S., and worsens or causes other respiratory ailments."
Cover did concede that "The NIH did say that respiratory irritants, such as air pollution, can trigger an asthma attack," then added, "but not that air pollution causes the disease."