The total emissions of 5 leading air pollutants in Pennsylvania fell dramatically from 2008 to 2011. Encouragingly, soot being dumped into the air fell 27% and sulfur dioxide pollution fell an astonishing 70%.
http://thebreakthrough.org/index.php/programs/energy-and-climate/deadly-air-pollution-declines-thanks-to-gas-boom/. The amount of carbon monoxide, nitrogen oxides, and volatile organic compounds (VOCs) also dropped substantially.
These statewide, total declines in pollution from point sources within Pennsylvania will prevent illnesses and premature deaths. Soot is really dangerous to human health, and its reduction should be especially celebrated. And so the drop in pollutants is great news, and Pennsylvania will receive even better news when data is available for 2012.
The question becomes, why is Pennsylvania's pollution dropping so sharply? The answer is primarily scrubbers installed on coal plants (something the BreakThrough Institute ignored in the linked to piece) and switching from coal to cleaner burning natural gas.
Though the statewide data is encouraging, it is also important to look at regional or local air pollution loads.
While Pennsylvania's overall emissions of air pollutants are falling substantially, some areas where gas drilling is concentrated do have significant new sources from gas production of nitrogen oxides and volatile organic compounds.
Gas production statewide emitted 16,542 tons of nitrogen oxides or about 8% of Pennsylvania's 2011 point source total, 2,820 tons of volatile organic compounds or 14% of the total, and 6,852 tons of carbon monoxide or 8% of the total. Those are significant amounts in the statewide data and can be a real local air pollution problem in some circumstances.
It should also be noted that gas production contributed about 0% of Pennsylvania's total soot and sulfur dioxide pollution. And soot is the most serious threat to human health.
While using more natural gas is helping to reduce the total emissions of leading air pollutants, regulators and the industry should install the best available technology on compressor engines, drilling rigs, fracking pumps, well completions, and other main sources of air pollution from gas drilling. Such measures can reduce air emissions by 90% from gas production.
By installing the best available pollution controls and avoiding diesel to fuel engines during gas production, Pennsylvania can gain substantial statewide air benefits, without creating local air pollution problems. Cutting local air emissions from gas production is possible and must be done.