ALEX CHADWICK, host:
The big finale at the Olympics is the marathon. That's on Saturday. We're checking back on air quality with Ken Rahn. He's professor emeritus of atmospheric chemistry at the University of Rhode Island, and he's a senior research scholar at Tsinghua University in Beijing. Ken, hello again.
Dr. KENNETH RAHN (Professor Emeritus, Atmospheric Chemistry, University of Rhode Island): Hi, Alex, nice to be with you again.
CHADWICK: On NBC last night, news anchor Brian Williams said that people told him the air in the city was the best it had been in 10 years. And I actually could see the stadium behind him in a sort of bluish tint to the sky. What's going on?
Dr. RAHN: I got a glance over the weekend, and the sky was beautifully blue. I mean, really, it was wonderful. And the air pollution index for that day was exceedingly low. Also, it was like 17. That's lowest since I've been keeping track.
This, I think, has to do with changes in weather patterns that appeared to start somewhere in the first week of August. The arrival of rainfall and winds from the northeast and form the northwest, which would bring in cleaner air, and in particular lack of strong winds from the south that would bring up the heavy levels of pollution.
CHADWICK: Yet, you've said earlier that the air pollution in Beijing mostly blows in from elsewhere. So these steps that the city officials have taken in recent months with changing traffic patterns and closing factories, really, that's not a factor here?
Dr. RAHN: Well, you know, I've been looking at the day they very carefully tried to decide what is really going on this summer. We know that the controls did something. It's just that I, at least, am unable to pick out their effects in the data so far.
CHADWICK: So how long is this going to hold, do you know, Ken? You know, the women marathoners, I guess, were lucky because they run over this weekend, and the air quality was very good. Then the..
Dr. RAHN: And it was raining. It was misting that day, too.
Dr. RAHN: So that's just perfect for marathoners.
CHADWICK: The men are running on Saturday. I wonder what it's going to be like for them?
Dr. RAHN: I don't think the situation is going to change very much between then and now. We now are in the mid 50s for air pollution index. It's not the greatest. but certainly, there's nothing to be concerned about. And over the weekend, things are going to get scattered. Winds are going to be variable, and there's some, I guess, some rain predicted, too. So it looks as if the air quality is going to stay quite acceptable through the rest of the Olympics and maybe a little bit cooler, too, on the ground.
CHADWICK: Ken, in your work as a scholar in Beijing, do you get any sense that China might really try to do something about pollution long term, air pollution, or is this just cleaning up while the visitors are in town?
Dr. RAHN: It's actually both. China has in place a regional air quality plan. They have tried to accelerate that plan for the Olympics. They're getting what they can out of this. To me, it doesn't appear to be very much so far, and I don't think there's any surprises in that because this is a long-term project.
In the United States, we've been at this for 40 years, and we're still working on ozone. We still have areas of noncompliance for ozone around the country. China, it's still a developing country. So where we talked about, you know, 30 or 40 years, you probably have to double or triple that for China. So we're going to be revisiting this for many, many years.
CHADWICK: Atmospheric chemist Ken Rahn who monitors the online air quality stations all around Beijing, and he's a visiting scholar there at Tsinghua University. We've reached him at his home in Rhode Island. Ken, thank you again.
Dr. RAHN: Always a pleasure, Alex.