‘After China, it’s India’s turn to take concentrated action against pollution’ | Mumbai News
Mumbai is in the headlines for its worsening air. But “publicity for the wrong reasons can be a motivator,” says Douglas Worsnop, noting that bad press over Beijing’s smog before the 2008 Olympics pushed China to clean up its air. Worsnop—a leading atmospheric chemist who helped develop key instruments to study pollution particles—has also worked on China’s clean air efforts. In Mumbai for the 14th Asian Aerosol Conference, the University of Helsinki professor spoke to Vaishnavi Chandrashekhar about lessons for India.Q: Tell us about the air pollution experience in China.A: I’ve been visiting China for 20 years, and I watched things get worse and then things get better. The govt there actually talks to scientists, more directly and more formally than anywhere else I’ve seen. That doesn’t mean the govt does exactly what the scientists say, but over time, they listen. And the govt in China, specifically, has the authority and the discipline to make things happen on a timescale of years. The air is still not fully clean there. There’s still work to do. But for five years or more, they made it a top priority, and things happened. And it’s still a high priority. China also took advantage of what had been learned in the US and Europe. In 1970, the US introduced the Clean Air Act, and it worked but it took us 40 years. The Europeans were roughly a decade behind us and now have caught up. The Chinese made the air dirty five times faster than we did, but they are cleaning it up maybe five times faster. But it took international headlines about pollution in Chinese cities to get concerted action. It’s now India’s turn. And India has the opportunity to do it even more efficiently, more scientifically.Q: What have we learned in recent decades?A: When the air was bad in the US, in the ’50s, ’60s, we didn’t know nearly as much, we didn’t have the instruments. We never studied the air in Los Angeles when it was at its worst. Now we understand the basic photochemistry better and we have better measurements. At the same time, the local sources are unique to each place. For example, in LA, the biggest problem in the ’60s were the cars. When China exploded their car (population), if they hadn’t had modern emission controls, they would have choked. In Delhi, a large fraction of the worst days is due to open and crop burning. China still has a problem with crop burning, but they’re trying to educate the farmers. What you need now is more measurements. That’s what happened around the 2008 Olympics in China. They scaled up measurements. There are 1,500 stations or so now, and you can call up the PM2.5 map of the country on your phone. Q: One thousand five hundred stations for the whole of China doesn’t seem much.A: That’s true, but it still gives you a picture. When you have a haze event like this (points to the Mumbai skyline outside) it’s widespread. But even when the sky looks cleaner, it doesn’t mean it’s clean. These networks give you that information.Q: What do advances in measuring pollution tell us?A: We figure out which emissions are most important. And we also get to understand the photochemistry. The haze we see today is accumulated photochemistry… To go back to the US, when the EPA (Environment Protection Agency) started regulating pollution in 1970, they started with total suspended particulates, and the biggest source of that was cement factories. And they forced the cement factories to clean up. And then they went to PM10 (larger particles), and that included construction dust. And then in 1997, they went to PM2.5 (smaller particulates), which stays in the atmosphere longer and has more health effects. China just did that faster.
