Further emissions cuts from the utility sector are needed to allow for ecological recovery in acid-sensitive areas according to the 2011 National Acid Precipitation Assessment Program Report to Congress.
Power sector emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx) must be reduced to below 1.1 and 0.44 million tonnes per year, respectively, by 2020 to reduce the number of lakes with acute acid deposition issues. To fully protect the lakes in the northeast, SO2 emissions would have to come down to 0.44 million tons per year or less. Ecological recovery in the southeast will take longer because the soil there retains sulphur.
The Cross-State Air Pollution Rule would, if implemented fully, cut SO2 emissions from 23 eastern states to 3.24 million tons per year (TPY) in 2012. NOx emissions would come down to 1.16 million TPY.
Power sector SO2 emissions would have to be cut by an additional 90 per cent to reach 0.44 million TPY relative to the emission level expected to be achieved under existing air quality legislation. To cut NOx emissions to 0.44 million TPY power sector emissions would have to fall by about 80 per cent. Sources outside of the power sector such as industrial boilers would have to reduce emissions by an additional 50 per cent, according to the report.
Source: Argusmedia 20 January 2012