When she was researching climate change in China’s Qinghai province several years ago, Catlin Powers was invited into the home of a local family of Tibetan nomads.
The tent was filled with noxious yellow smoke that stung her eyes and left her gasping for breath. “I had air monitors with me so I took some measurements and found that the air inside the tent was 10 times more polluted than the air in Beijing.”
The smoke was produced by the family’s cooking stove, a simple construction fuelled by yak dung and wood. Dr Powers, who lectures on sustainable technology at Harvard, learned that the sooty particles and greenhouse gases caused appalling health problems among the nomads.