Air Pollution

HEI's Greenbaum discusses health effects of air pollution, science behind policy

Is particulate matter a contributor to heart attacks and asthmatic inflammation? Dan Greenbaum, the head of the Health Effects Institute, a Boston-based organization that studies all things air pollution, joins OnPoint to discuss the health effects of air pollutants, the science behind policy and new amendments for the Clean Air Act.


Darren Samuelsohn: Hello and welcome to OnPoint. I'm Darren Samuelsohn. Joining us today in the E&ETV studios in Washington is Dan Greenbaum, the head at the Health Effects Institute, a Boston, Massachusetts-based organization that studies all things air pollution. Mr. Greenbaum thanks for being with us.

Dan Greenbaum: Thanks for having me Darren.

Darren Samuelsohn: Let's start off talking generally about air pollution. Give us a sense, when industry, in the Bush administration these days, they talk about air pollution, they like to caveat everything with the fact that air pollution has been declining steadily over the course of the last 25, 30 years while the economy has been soaring. First off, is that it true assessment that they're giving?

Dan Greenbaum: Well, it is absolutely right that air pollution's been going down. There have been a lot of actions taken over a long period of time and contrary to what some people have felt, that has happened while the economy has gotten better. So it doesn't seem like the controls that have been put in have been bad for the economy. On the other hand, the health science has begun to show us that even at the lower levels we have today there continue to be issues.

Darren Samuelsohn: Does the bad news kind outweigh the good news do you think watching this issue?

Dan Greenbaum: Well, that's always a difficult balance. I mean, we've made a tremendous amount of progress, and I don't think anybody should deny that, but the continuing size of the impacts, particularly for exposure to particulate matter air pollution, give us pause and say, we better keep our intention and our eye on the ball.

Darren Samuelsohn: For the layman out there, let's get a sense. What are the health effects from particulate matter, from ozone and then from toxics? Those are kind of the three things that I think are probably the most on people's agendas these days.

Dan Greenbaum: Sure. Well, there is quite a bit of data that's been collected over many years, particularly on ozone, which has been known for some period of time to cause a lot of irritation, inflammation in the lung, to cause people who have asthma to go to the hospital more or kids to miss school or have asthma attacks. It doesn't appear to start up new cases of asthma, but it does have this serious short-term impact. Particulate matter has been known for a long time to have some similar effects, but in recent times, at lower levels, studies have pretty consistently shown that there's a relationship between exposure and increases in premature mortality, which is one of the largest kind of impacts that air pollution has ever seen.

Darren Samuelsohn: Let's talk about some of the, I guess, the newest studies that have been coming out lately. First off I guess, how many studies are going on, do you think, at any one point in time on air pollution?

Dan Greenbaum: Well, we actually have maintained, historically, a Web inventory of the studies and it's hundreds of studies now, particularly over the last five years ever since Congress sort of said, after 1997, that we really needed to do more research and more money went into that. Those range from just good quality air monitoring studies to laboratory studies to epidemiology studies out in the field.

Darren Samuelsohn: And they're happening in the United States and around the world too?

Dan Greenbaum: That's right, and one of the things we've seen is actually increasingly studies done in one country are then used to help inform decisions in another.

Darren Samuelsohn: Do we see that in some countries they're finding some answers that are not being found in other countries as well?

Dan Greenbaum: Well, there are differences. In fact, my institute's funding a study now bringing together European and North American investigators because the findings in the European studies were somewhat different in terms of which pollutants were causing effects than the findings in the U.S.

Darren Samuelsohn: OK, and then I guess there's one study that you brought to my attention before the show here, it has to do with heart attacks and people that are traveling in cars, in traffic, also on bicycles and public transportation. Give us a short synopsis. What did they find and how is that affecting where we are today?

Dan Greenbaum: Well, that's a study we funded actually for some investigators in Germany because they had the database. They looked at people who had already had a heart attack, but had survived it and then they went in and interviewed them and asked them what had they been doing in the days and hours beforehand? Not surprisingly they found that if they'd been doing something stressful, heavy exercise, that was often correlated with having the heart attack. But to most people's surprise, they found that if they'd been spending time in traffic, whether driving or in a bus, that also was pretty heavily correlated.

Darren Samuelsohn: It didn't match up though with, I think, what some people had found in Boston a couple of years before, is that right?

Dan Greenbaum: Well, our interest in funding the study was to see whether it also was correlated with exposure to air pollution in those hours before the heart attack and unlike a study these investigators had done in Boston a few years ago there wasn't that short term effect of air pollution. It doesn't necessarily mean air pollution isn't part of it, but as we know, there's a lot of stress in driving, there's a lot of noise, there are a lot of other things that could also help trigger heart attacks.

Darren Samuelsohn: Are there more studies like that going on or that are going to be going on pretty soon that will try and pin this down even more?

Dan Greenbaum: Yeah, we actually are going to publish the results fairly soon of a different type of study where we've actually had investigators track people who have implanted pacemakers to see when those triggered off and to see whether the triggering off seemed to be correlated with air pollution. There are several of those going on around the world and we're going to be trying to see if we can combine and compare across all of those.

Darren Samuelsohn: Another study that you brought to my attention, which was interesting, found people volunteering, that came in and they were asthmatic and as well as healthy people and they were breathing in fine particulate matter and the results were kind of interesting. Not what you expected or not what the researchers expected.

Dan Greenbaum: Yeah, well this was a study with ultra-fine particles, very, very tiny particles. You couldn't see them if you were looking at them in the air and some scientists have thought they may be the most toxic thing, because they do have the possibility of getting deeper into the lung. There was evidence in the study that these particles got deeper into the lung, but there was very little evidence of increased inflammation or other effects compared to when those same people were given, breathing clean air.

Darren Samuelsohn: Bringing this home to, I guess, where we are right now, the U.S. EPA has to review its standards every five years for six major criteria pollutants. I'm not going to ask you to remember them and name them right here, but I'm sure you can. Right now they're looking at fine particulate matter and they're looking at ozone and actually this week they're looking at fine particular matter. Give us a sense, what have the scientists from EPA said at this point in where it EPA headed right now?

Dan Greenbaum: Well, I think, first of all, they've said that the science that they had six or seven years ago, in 1997, has gotten stronger. My institute and others we've done re-analyses of the old studies. There are new studies that have been funded and I think in general the epidemiology studies and some of the toxicology studies are better than they were in the earlier round. So they feel the evidence is stronger. They've secondly said that, gee, there's still no evidence that there's a threshold, a safe level below which people are exposed and there aren't effects. So they're proposing, at least at this point, to tighten the standards, to reduce them to a lower-level than they were set in 1997.

Darren Samuelsohn: Industry argues sometimes that the science isn't fair and what's to say that they're not right in terms of making that argument?

Dan Greenbaum: Well they're raising, they raise good questions. There's always questions about the science and you need to pay a lot of attention to those so you don't erroneously go after the wrong things, spend a lot of money and don't really help public health. But I think we have tested the statistics pretty hard in these cases. Tested these studies pretty hard and although there continue to be questions, they've held up pretty well.

Darren Samuelsohn: When you have a study that finds an answer that's maybe different or a result that's different than what you had set out for, take, case in point, I guess the volunteer study, does that bolster the argument of people who say that less regulation is needed or maybe we should pull back from existing regulation?

Dan Greenbaum: Well, it can add to the arguments that say let's slow down or let's make sure we're doing the right thing here. Good science and good decisionmaking never rests on one study, but what you need to do is then look at that, the results of that study, you need to evaluate it carefully and then decide whether you still think there's enough evidence or you might want to slow down. Let me give you an example, that study dealt with people who were mild asthmatics and exposed them to ultra-fine plain carbon particles, which most people wouldn't have thought were very toxic. It was a safe study that we could do first. These were volunteers. They had to give their consent to do this. We might now move to a different study that used particles that had some metals on them, for example, that might cause affects or people, there may be volunteers who are slightly more asthmatics who would be willing to participate in such a study. These can be done safely, but we may see effects in those that we didn't see in this first one.

Darren Samuelsohn: Do these studies give you a real world sense of what's actually happening outside of the laboratory?

Dan Greenbaum: Well, that's always a challenge. The laboratory usually likes to use a very specific exposure that doesn't quite relate to what's outside, but we had actually done a similar study to that one a couple of years ago in Southern California where the volunteers were exposed to concentrated ambient particles, actual ambient particles and that gives you a little bit better sense of whether those particles are causing effects. Again, mild asthmatics, healthy people, there wasn't a lot shown, although there are now further studies being done now in that area using different types of particles.

Darren Samuelsohn: Are we monitoring enough for air quality around the country? Are there enough air monitors in every city and in the rural areas around the country to sense how much, how air quality is improving or declining?

Dan Greenbaum: Well EPA has done, I think, a very good job of expanding the monitoring network over the last five years. The states have worked with them. We're getting much better information. It's still not perfect. There's still some places where it's not giving us everything we need. One of the key questions is the question have are some components of the mixture of particles more toxic than others? We're just now having about three years of data of that from 50 sites around the country and now we're going to need to do health studies with that.

Darren Samuelsohn: Let's turn to the regulatory side of things. Taking all the science that you're dealing in, now EPA obviously has to deal with --

Dan Greenbaum: Right.

Darren Samuelsohn: What the scientists produce. A lot of EPA programs have come out of last 10, 15 years since the Clean Air Act amendments of 1990, you have reformulated gasoline in cities with dirty air. Most recently you have the new Clean Air Interstate Rule, reducing power plant pollution in the East. Diesel standards and I know you've played a major role in.

Dan Greenbaum: Right, right.

Darren Samuelsohn: Are all those combined enough to reduce the health risks right now? I mean do we need to do more in terms of regulation?

Dan Greenbaum: Well, they are going to get us a long way. I don't think there's any question that there'll be substantial reductions, particularly in the eastern part of the U.S. where some of the worst levels of particle and other pollutants are. I think that that is also the most cost effective way often to do these things, to do it on a multi-state basis or on a national basis rather than in one state at a time. California may be an exception to that because they have such an intense problem. But will they get us all the way there? Well if our experience in ozone is any indication, we've been working in that for about 30 years, we've made tremendous progress, but we still have some stubbornly nonattainment areas that, where people are exposed to levels that are higher than the standards allow. We're still going to need to come back and say, "Well, are there more things we need to do?"

Darren Samuelsohn: In Los Angeles for example I mean, they've got problems that date back for a long time. I mean, aside from, I guess, moving Los Angeles to another place or knocking the mountains down, is there anything that Los Angeles can do?

Dan Greenbaum: Well, I think some of the kinds of things that are going on, the reductions that are going to show up with the new diesel rules that are in place, the efforts that are under way in California and elsewhere to accelerate the replacement of the older diesels, which are the bigger problem really than the new ones, which are quite clean, are going to make a difference and they're going to help. They have made, I mean we shouldn't forget that for example, carbon monoxide which was a very, very serious problem in L.A., has been reduced dramatically to meet the standards in L.A. or nearly need to standards in L.A., despite massive growth in traffic and that's because each car is a lot cleaner than used to be.

Darren Samuelsohn: Mobile sources, I wanted to get at with you, we're talking cars, trucks, buses. They also emit air toxics and environmental groups, I think, state and local officials have been trying to push EPA to regulate mobile source air toxics for quite a while. I think they've lost in court in trying to push EPA to do this. What are the health risks of mobile source air toxics, first off, and then should they be regulated?

Dan Greenbaum: Well, there are two kinds of things that air toxics can create. One, and the one that people focus on the most, is that some of them are either known or probable human carcinogens. So if you get the right exposures you could be engendering some number of new cases of cancer. The second is there is some level of irritation, lung inflammation, those kinds of things, which are not dissimilar from what you might see from ozone. On the first one, I think, that there has been quite a bit of effort to try and reduce probably the biggest exposure and that is to benzene and which is a known human carcinogen. And the reformulated gasoline you mentioned a minute ago, actually, dramatically reduced benzene in the fuel. We've seen that measured reductions in benzene exposure. The vapor controls that have gone on gasoline pumps have also reduced that and there are also efforts to reduce these from other sources because they don't only come from mobile sources. But there are questions right now and we're actually conducting a review of all the existing science about how much further and where EPA should take this in the next steps.

Darren Samuelsohn: Six years ago you were in charge of a blue ribbon panel that looked at methyl tertiary butyl ether, MTBE as it's widely known --

Dan Greenbaum: Right.

Darren Samuelsohn: And you recommended its phase out six years ago. Today Congress is still debating whether or not they should phase out MTBE and it's been tied to a whole bunch of other things, the Arctic refuge, etc. in an energy bill.

Dan Greenbaum: Right.

Darren Samuelsohn: The health risks of MTBE are, what are they?

Dan Greenbaum: Well, they're actually pretty mild. The evidence we have don't suggest that it's, there is some limited animal evidence of possible carcinogenic activity, but it doesn't really suggest that these are human carcinogens. We don't have that. They're not terribly irritant kinds of things that go on and ironically, because of the reasons that it's problematic in water, that it smells and tastes bad, it actually reduces the risk because as soon as people know it's there they stop getting exposed, they stop drinking the water. That creates a different problem and which is what drove our recommendation, which is, the water suppliers can't use the water because nobody will drink it.

Darren Samuelsohn: OK.

Dan Greenbaum: And they have to shut down wells until they get it cleaned up, but not so much for public health reasons.

Darren Samuelsohn: So it's more of an aesthetic issue than it is health?

Dan Greenbaum: Yeah, and people don't want to drink water that smells like that.

Darren Samuelsohn: OK. Turning back to, I guess, the regulation side of things. One of the arguments that the administration has been making lately has to do with collateral benefits, like you're accomplishing one thing with one regulation, therefore maybe you don't have to do something with another one because you're also getting at the same issue. This happened with the Clean Air Interstate Rule and mercury. What's your take on collateral benefits, when one rule does something and helps out with something else? I mean how does that play in your eyes and as a former regulator in Massachusetts under Governor Dukakis, I mean, is that something that works?

Dan Greenbaum: I think it's what you always want to look for, frankly. I co-chaired a committee at the National Academy that recommended, just a year ago, that we really needed, in air-quality management going forward, to do much more of the multi-pollutant kind of efforts where you're looking at, yeah, we need to control these, these two or three pollutants, but if we can get extra benefits and reduce other ones let's go for that option and go for that. Obviously the question will always come to is that enough? So going back to the mobile source arena, for years we went after volatile organic compound emissions and nitrogen oxide emissions. That had reduced benzene emissions, but not enough. So then there were additional controls on the amount of benzene in the fuel to further reduce it and that's in some ways analogous to the kind of debate that's going on around mercury.

Darren Samuelsohn: I know you're not a lawyer, but right now these days, you have Republicans on the Hill saying that litigation is miring down the Clean Air Act and it's the reason why market-based approaches need to be put into place, a la the Clear Skies Initiative that the president has proposed. Is litigation really a problem with the Clean Air Act? I mean, litigation is a part of the checks and balances of the democracy that, I guess, we have in the country. But is litigation causing problems with reducing air pollution?

Dan Greenbaum: While there are certainly more lawyers involved in the implementation of the Clean Air Act than there were 10 years ago or 20 years ago and there's a lot more contention around it. Although I think if you look at the record on progress we've been making it's hard to argue that it has stopped all the progress. I would actually say though that there are places where we've been doing the same thing for a number of years and there are places where bureaucratic ways of doing things become entrenched and there are better ways sometimes to do these things. The kind of trading program that was put in the Clean Air Interstate Rule and the Clean Air Act in 1990 was amended to do even further than that, has actually resulted, that kind of trading if properly instituted can result, for the right pollutants, in substantial reductions and much, much lower costs than you would get if you required every single plant to do the same thing. I don't think we're going to eliminate the litigative parts of this because it is a law and the lot is at stake usually in this. But I think we've seen a number of cases where progress has been made in spite of that.

Darren Samuelsohn: Are the stars aligned for Congress to pass a new Clean Air Act set of amendments anytime in the near future?

Dan Greenbaum: Well I once testified in front of the Senate, not long after the 1990 amendments went through, and at that hearing somebody was proposing that they should be reopened. This was about three years after it. Senator, the late Senator [John] Chafee, was on the committee and turned to his colleague, the chair the committee, and said, "I will never again sit in room 327 of the Dirksen building to deal with the Clean Air Act." It takes a lot to do that. I think there clearly are opportunities to do that and to think about that. At some point I think the critical mass will get there to sort of say, "Yes, make that go forward." But the act has gotten thicker, many more pages and it gets more complicated each time.

Darren Samuelsohn: And keeping us very busy.

Dan Greenbaum: Yeah.

Darren Samuelsohn: Mr. Greenbaum, thank you very much for being here. I'm Darren Samuelsohn for OnPoint. We'll see you again next time.

[End of Audio]



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