Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 30. huhtikuuta 2007 klo 14:35 (GMT)
Air pollution season begins May 1 and lasts through the end of September. The U.S. Environmental Protection Agency (EPA) has designated this week as Air Pollution Awareness Week, so I'll be pointing people to the EPA web site designed for the occasion. We worry most about air pollution in the summer for two reasons:
1) The pollutant of most concern in the U.S. Is ground-level ozone. Ozone is a colorless odorless gas. It's the same kind of gas that's found in the ozone layer. But in the ozone layer, high in the Earth's stratosphere, ozone protects us from the sun. At ground level, where we live, ozone pollution is unhealthy to breathe. Ground-level ozone forms when nitrogen oxides and gaseous carbon compounds from cars, trucks, power plants, industries, and some consumer products cook in the sun. Intense sunlight and hot temperatures make the most ozone. Thus, hot summer days in late afternoon have the highest ozone pollution--unless strong winds disperse the foul air.
2) Summertime has the the greatest incidence of multi-day periods with clear weather and light winds. These "air stagnation episodes" allow pollutants to build up, since there is little wind to disperse the stuff. Air stagnation episodes are much less common during other times of year, when low pressure systems and their attached cold fronts and warm fronts bring strong winds that keep pollution levels lower.
I'll have a new blog Tuesday or Wednesday, and take a look at last year's pollution season. Is air quality improving in the U.S.?
Figure 1. Map of hurricane buoys maintained by the National Data Buoy Center. Image credit: NOAA.
New hurricane buoys on-line
Two new ocean buoys are now on-line to help monitor hurricanes, thanks to over $2 million in special hurricane funding approved by Congress in the wake of the Hurricane Katrina disaster in 2005. Buoy 42059, a few hundred miles south of Puerto Rico, and buoy 41043, a few hundred miles north of Puerto Rico, are strategically placed to offer data in area where hurricanes frequently traverse. Six more buoys are scheduled to come on-line in the next year, and these will be a big help in tracking hurricanes.
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