PWS oil tankers creating less air pollution

Following the introduction of low sulfur marine fuel, oil tankers carrying crude oil from the Valdez Marine Terminal are generating less air pollution in the Prince William Sound region, according to a recently published report, commissioned by the Prince William Sound Regional Citizens’ Advisory Council. The pollutants investigated consist of sulfur dioxide, particulate matter and nitrogen oxides.

Under regulations developed by the International Maritime Organization, since August 2012 large ships operating within the North American Emissions Control Area, a zone extending out to approximately 200 miles from the U.S. coastline, have been required to use fuel with sulfur content not greater than 1 percent. In January 2015 the IMO tightened this limitation to a maximum 0.1 percent, the advisory council said.

The study that the advisory council commissioned estimated emissions levels as a consequence of tankers burning fuels with three different levels of sulfur content: 2.7 percent, 1.0 percent and 0.1 percent. The study found that, by using fuel limited to 0.1 percent of sulfur, tanker exhaust emissions would drop annually by 426 tons of sulfur dioxide, 33 tons of particulate matter and 29 tons of nitrogen oxides when compared with fuel with 2.7 percent sulfur content. That represents a 96 percent reduction in sulfur dioxide emissions, an 80 percent reduction in particulate matter emissions and a 6 percent reduction in nitrogen oxide emissions, the study report said.

Although these findings indicate that the new fuel standards will have improved the air quality in the Prince William Sound region, the study did not attempt to quantify the resulting benefits in terms of human health, environmental health or local air quality, the advisory council said. Apparently low sulfur fuel costs about 60 percent more than traditional fuels.

- ALAN BAILEY