Article

01 October 2004

Particulate matter and visibility

Blake Gettig

The Great Wall of China. Click image to enlarge.

Tian'anmen Square and the Great Hall of the People. Click image to enlarge.

People and nature have special ways of dispersing aerosols into the sky. The images here of the Great Wall of China and the Tian'anmen Square in Beijing were taken by Blake Gettig, an engineering major at Texas A&M University, who writes about the latter:

"This photo was taken at midday on 8 August 2004 from the Forbidden City looking out on Tian'anmen Square and the Great Hall of the People. Here the air quality is so poor that the photo looks as if it was taken on a rainy day. The air includes a mixture of dust, soot from coal-fueled power plants and factories that are not required to use scrubbers, and pollutants from the ever increasing number of automobiles. Within minutes of being exposed to the polluted air, the visitor experiences burning eyes, a coated throat, and headaches or dizziness."

Air pollution over Eastern China at noon
on 8 August 2004 modeled by the Navy Research Laboratory's NAAPS aerosol forecast model. Click image to enlarge.

Rapid industrialization, dense automobile traffic and desert dust have made Beijing among the world's most polluted cities. Other cities and regions around the world also suffer from severe air pollution, including the Los Angeles region, Mexico City, São Paulo, Brazil and others. Amateur scientists can track air pollution events using the Sun and Sky Monitoring Station, a 4-channel sun photometer and radiometer available from the Society for Amateur Scientists.