http://pediatrics.aappublications.org/cgi/content...

Some findings:

"…Researchers found that particulate air pollution did drop by about one-third during the two-week Olympic period. But coarser particulate matter, PM 10, exceeded levels the WHO considers safe about 81 percent of the time, while the smaller particulate pollution PM 2.5, which can cause more serious health consequences, exceeded WHO guidelines 100 percent of the time.

"It was a giant experiment and a noble effort. But in the end, the extra added measures didn't help reduce PM concentration as much as had been expected," said Staci Simonich, an associate professor of chemistry and toxicology at Oregon State University who worked on the study.

There has been no evidence so far of any health problems linked to the short-term exposure of athletes or spectators during the Olympics, researchers noted.

Further investigation suggested that weather conditions, such as rainfall and strong winds from the north and northwest, played a much larger factor in clearing the air than the pollution curbs.

Meteorological conditions accounted for 40 percent of the variation in concentrations of coarser particulate matter, while pollution control measures accounted for only 16 percent, the study said…"

Some findings:

"…Researchers found that particulate air pollution did drop by about one-third during the two-week Olympic period. But coarser particulate matter, PM 10, exceeded levels the WHO considers safe about 81 percent of the time, while the smaller particulate pollution PM 2.5, which can cause more serious health consequences, exceeded WHO guidelines 100 percent of the time.

"It was a giant experiment and a noble effort. But in the end, the extra added measures didn't help reduce PM concentration as much as had been expected," said Staci Simonich, an associate professor of chemistry and toxicology at Oregon State University who worked on the study.

There has been no evidence so far of any health problems linked to the short-term exposure of athletes or spectators during the Olympics, researchers noted.

Further investigation suggested that weather conditions, such as rainfall and strong winds from the north and northwest, played a much larger factor in clearing the air than the pollution curbs.

Meteorological conditions accounted for 40 percent of the variation in concentrations of coarser particulate matter, while pollution control measures accounted for only 16 percent, the study said…"