By Sid Perkins
Emissions from oceangoing ships substantially boost acid rain on shore and may account for more than a quarter of the ground-level ozone in some coastal areas, a new study reveals.
Many commercial vessels, especially long-haul cargo ships, spend much of their time in international waters. Nevertheless, exhaust from these ships contributes to onshore pollution: Studies have shown that about 70 percent of shipping occurs within 400 kilometers of land.
To assess the amount of pollution spewed by ships, as well as pinpoint where those emissions occur, Stig Dalsøren, an atmospheric scientist at the University of Oslo in Norway, and his colleagues analyzed data gathered worldwide during 2004.