"Most people recognize that smoking is the worst thing you can do to your health. The next worst thing you can do is to be around smoke, and cook fires are equivalent to a thousand cigarettes burning in the kitchen per hour. Babies may not smoke, but they are in these homes", said professor Kirk Smith at Peking University recently.

When talking about air pollution, we normally think of air pollution as being outdoors, such as industrial pollutants, automobile exhaust etc, and indoor air pollution had been overlooked for a very long time.

Kirk R. Smith, a member of the National Academy of Sciences and professor of global health at the University of California at Berkeley, sounded the alarm that  solid fuels, on which almost half of the world’s population rely for cooking and heating, account for about 2 million deaths every year when burned in open fires or traditional cook stoves.

In 2008, indoor air pollution was listed as one of the world's worst pollution problems, according to Blacksmith Institute.

As the first scholar to recognize the health risks of indoor air pollution and pursue the solutions to it for over 30 years, Smith has his own reason.

Back to 1968, Smith earned his bachelor degree in Physics and Astronomy at UC Berkeley. But he always cares about helping people. “I want to help people using my physics background, and initially I worked on radiation. When I first came to China in 1981, I worked on the nuclear safety issues with a group of Tsinghua University. Then I started looking at the air pollution in Asia, I realized the risk was so high and it was much higher than nuclear power. It didn’t make sense to me and nobody was doing that at that time, so I decided to shift.”

Realizing the risks, Smith and his students started to carry out field studies in developing countries especially in China and India.

“In 1990s, we did measurement of the emissions from household air pollution, different types of stoves and different types of fuels, indoor and outdoor air pollution in China, India, Nepal and countries near Himalayas Mountain because black carbon goes in the lands of glaciers. We’ve carried out studies in Yunnan and Tibet on black carbon emission”, he said.

In his eyes, China has made great progress to reduce the exposure to household air pollution. Many families in the cities shifted their traditional stoves to gas or electricity in 1980’s and 1990’s. “China has a big national program and it is remarkable”.

Today, even though the public realize the solid fuels for cooking and heating have damaging effects on health and climate change, they are still using them. “In China, there is a lot of coal use, so lung cancer risk is higher for coal than for biomass. In fact, I think it is a mystery that China has a high rate of chronic obstructive pulmonary disease (COPD) for some reason, even those who are non-smokers have a much higher rate than the average”, he pointed out.

Health always comes first. According to him, women and young children in the developing countries get exposure to indoor air pollution due to household fuels. They inhale the indoor smoke that contains a range of health-damaging pollutants, such as small particles and carbon monoxide, and particulate pollution levels may be 20 times higher than accepted guideline values, which links the diseases of acute lower respiratory infection, low birth weight, pneumonia, tuberculosis, cancer and COPD etc.

“Young children and their mothers are getting exposed to indoor air pollution and they are most at risk”, Smith cares for them, “Young children have very sensitive lungs and they are not running around like school age kids, so they just stay at home with their cooking mothers and that’s why they have high exposure to household air pollution, people need to do more to make cooking safer for women and children”.

So does China. Despite the big changes in the past 30 years, China needs more progress.

Smith noted, “The expectations changed, now China should have a second national program, focusing on clean combustion. They need more new stoves and they need to move away coal to clean biomass finally.”

In Shanxi province, his former students are having a project advised by him to substitute dirty coal stoves with clean biomass stoves, and the latter has a blower and produce good and clean combustion from corn cob using. “Farmers are happy about it. They don’t have to buy coal and get clean combustion. Each stove costs 700-800 RMB, 200 RMB of which is paid by farmers and the carbon market pays the rest.”

Currently, he and his team are doing research outside of six ring of Beijing as well. He hoped that the rural area of Beijing would completely use clean energy in 4-5 years.

Kirk Smith was awarded the 2012 Tyler Prize for Environmental Achievement recently, in recognition of his contributions to understanding the health consequences of household air pollution from use of simple biomass fuels such as wood and cow dung. As Bernard D. Goldstein, his college in the field, said:”Dr. Kirk Smith has done more for the health of the largest number of individuals through the world than any other health scientist since Jonas Salk”. (Jonas Salk, an American medical researcher and virologist, was best known for his discovery and development of the first polio vaccine.)

“It is very nice to be here, I’m coming to China for more than 30 years. A lot of changes, but there are still a lot of challenges in the environmental health arena”. Smith said in his opening remarks for the lecture at Peking University. He has collaborated with his PKU colleagues for many years and serves the advisory board at College of Environmental Science and Engineering.

 “You just have to follow the risk”, Smith said, “don’t get diverted, always do good science and focus on the things that are going to help people, even though it is not easy to do in the academic environment”.

Interviewed and Reported by: Zhang Jiang, Dong Zhiyao