Tibet air quality near perfect

Tibetans living around the sacred Nam Co Lake in Tibet breathe in almost perfectly clean air, as in pollution-free Antarctica, new research has found.

Scientists reached the conclusion after tests found the Aerosol Optical Depth (AOD) of air samples stood at 0.029, a reading comparable to that in Antarctica, said Cong Zhiyuan, deputy head of the Qinghai-Tibetan Plateau Institute under the Chinese Academy of Sciences (CAS).

The AOD measures particular matter like sand and dust in the air. The lower the reading, the cleaner the air. "The Nam Co area has the cleanest air on earth," Cong concluded.

The PM2.5 reading of the area on an average day was 10 micrograms/cubic meter. That was one third of the standard set for national parks.

PM2.5 is a measurement that tracks particles smaller than half the width of a hair. The average PM2.5 reading in Chinese capital Beijing from Wednesday to Thursday was 137 micrograms/cubic meter.

Nam Co, with an elevation of 4,718 meters, is regarded as a sacred lake in Tibetan Buddhism. The pastureland around it is similar to other herding grounds on the plateau.

Kang Shichang, a CAS research fellow stationed at Nam Co, said the region is relatively free of pollution because most residents are herders and there is little human activity that could affect the air quality.

Kang said the pollution-free environment provides a perfect site for scientists to conduct research on the ecology.