Air Testing After Sept. 11 Attack Is Both Perplexing and Reassuring
The ground-level atmosphere of Lower Manhattan has become one of the most intensely studied and sampled environments on the planet. Air monitors have been hung from trees and strapped to the belts of truck drivers. At least 11,000 people who worked at ground zero have had chest X-rays. Thousands more have been interviewed by researchers. What has been learned, scientists say, will have a far-reaching effect on urban disasters in the future.