Paved surfaces can foster build-up of polluted air

By Fei Chen, Shiguang Miao, Mukul Tewari, Jian-Wen Bao, and Hiroyuki Kusaka
Boulder, CO (June 07, 2011)- New research focusing on the Houston area suggests that widespread urban development alters weather patterns in a way that can make it easier for pollutants to accumulate during warm summer weather instead of being blown out to sea. The international study, led by the National Center for Atmospheric Research (NCAR), could have implications for the air quality of fast-growing coastal cities in the United States and other midlatitude regions overseas.


They found that, because pavement soaks up heat and keeps land areas relatively warm overnight, the contrast between land and sea temperatures is reduced during the summer. This in turn causes a reduction in nighttime winds.
In addition, built structures interfere with local winds and contribute to relatively stagnant afternoon weather conditions.
Houston, known for its mix of petrochemical facilities, sprawling suburbs, and traffic jams that stretch for miles, has some of the highest levels of ground-level ozone and other air pollutants in the United States. State and federal officials have long worked to regulate emissions from factories and motor vehicles in an effort to improve air quality.
The new study suggests that focusing on the city’s development patterns and adding to its already extensive park system could provide air quality benefits as well. “If you made the city greener and created lakes and ponds, then you probably would have less air pollution even if emissions stayed the same,” Chen explains. “The nighttime temperatures over the city would be lower and winds would become stronger, blowing the pollution out to the Gulf of Mexico.”
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