Yesterday MDN reported the story that air pollution in Pennsylvania overall has gone done significantly from 2008 to 2011 due to the increased use of Marcellus Shale gas now being mined and used (see “Thank You for Fracking” – Air Pollution Goes Down in PA). The reason air pollution has gone down is mainly due to the switch away from burning coal to burning natural gas.
However, closer analysis of the data (MDN has not been able to get a copy of the full report—yet) shows that in PA counties with a lot of shale drilling, certain kinds of air pollution went up during that period even though the state average went down. Why? Mainly because of (we’re guessing) the increased use of diesel engines used in the equipment operating at drill sites and from the large number of trucks coming and going to drill sites. Compressor plant emissions also contribute to the increase.