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Health Impact Of Air Quality Alerts

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Air pollution watches are common this time of year. They’ve been around since 2000, but rarely does anyone say what they mean. In a KERA Health Checkup, Robert Kent, Director of Environmental Programs for the North Texas Commission, explains the alerts are a warning about ozone in the North Texas air.

Robert Kent: Ozone is basically three oxygen molecules that have been bonded together. It’s highly reactive and unstable and so when it gets into the lungs then it ends up causing coughing, throat irritation, pain and burning in the chest and chest tightness. Additionally, if you have asthma or emphysema it can aggregate those conditions.

They’ve done some studies about what happens when we have ozone in the area and they’ll find that trips to the emergency room increase. There are more people who call in sick to work. There are more students who take absent on days when we have those. And so ozone definitely has an impact on the health of the general population.

Baker: Usually when the media gives those various levels, they just basically say, “We have an ozone alert at level orange.” But no one ever really says what that means. So what does each level represent?

Kent: So they’re color-coded on a scale so green, no problem at all. Yellow is moderate. Orange is unhealthy for sensitive groups – sensitive groups would be anyone that has respiratory problems. This would be people with asthma, emphysema, or other type of lung conditions.

Baker: So on an orange alert day, what should such people do?

Robert Kent: Individuals who are sensitive to ozone pollution should limit their outdoor activity. People who are not sensitive to ozone pollution, who don’t have asthma or emphysema or other lung conditions, they may have some effects if they are doing a lot of outdoor exertion. So if they’re working out a lot, or running, or playing basketball, they may end up feeling some of the impacts from ozone pollution on days like that.

Then you move up to red, which is unhealthy for pretty much anyone. And then you can move on to higher levels of maroon and purple, which are hazardous and very unhealthy. We haven’t had a level above red in many, many years. But this year we’ve already had one or two days that were red, and last year we had one day that was red as well.

Baker: I was just wondering, what would all of this mean for someone who is in reasonable good health?

Kent: The EPA does some different types of activity levels that people who do not have lung conditions may start feeling ozone. So on a day that’s even at orange or red, someone who’s doing eight hours of intermittent outdoor work – so lawn work, mowing the lawn. Even at an orange level or particularly a red level, they may start feeling some impacts from ozone. So this could be tightness in the chest, inability to get a really deep breath, coughing, itching in the lungs, that type of feeling.

Baker: What sparks an ozone alert to begin with?

Kent: The Texas Commission on Environmental Quality, they do forecasts on the day ahead. So they look a a variety of factors based on the weather, wind patterns, temperature, and also what they’re expecting from traffic patterns in the area that will end up predicting if they think there may be an ozone alert the next day.

Baker: Now doesn’t all this have to do with how much the wind is moving?

Yes. So Ozone is formed by the combination of a variety of different pollution. So some of this is car exhaust, some of this is coming from vapors and fumes like you might find in the gasoline station. And those end up going into the lower atmosphere where they mix with sunlight and heat, and then on a very still day, they just sit tight and they don’t move. Consequently, you’ll have these chemicals all baking in the lower atmosphere, turning into ozone. And then on those days they’ll slowly drift across the Metroplex. And so on various still days it doesn’t go anywhere and it doesn’t dissipate, and consequently we’ll have higher ozone levels on those days.

Baker: Which leads me to wonder: just how bad is the air in North Texas?

Kent: Air quality has been steadily improving for the last ten to fifteen years. The main pollution that we have to deal with in North Texas is ozone. So if you look back at the numbers the last ten years, we’ve gone down from readings like 105, 110 parts per billion, down to two years ago when we were at 86 parts per billion. But the last two summers, because they’ve been so hot, we’ve had unusual weather conditions. They’ve actually slowly been starting to rise again.

Baker: Is that why the American Lung Association doesn’t look very kindly on this area? I think they’ve listed us as one of the most polluted areas in the nation.

Kent: For ozone pollution, that is correct. We get a B for particulate matter, which is alright, But for ozone pollution, they have us at an F.

Baker: So then what can people do to help with the pollution problem here?

50 percent of the ozone pollution problem is going to be caused by people driving their vehicles on a single occupancy basis. So anything you can do to drive less will make a big impact. A lot of the pollutants that end up causing ozone come from gasoline vapors that are escaping out of your vehicle. So if you can wait to fill up your vehicle after dark, it will help keep some of those emissions out of the sunlight and out of the heat where they bake into ozone. Another thing you can do is try to put off your lawn work into the weekends.

The small engines that run your weed-eater and your lawnmower end up releasing a lot of the emissions that end up causing ozone. And so on weekdays when we have a lot of traffic on the highways, we have a lot of people who are out driving. If we’re then running our lawnmowers those days as well, that’s just adding to the problem. We can help spread out some of those emissions to days that usually aren’t going to be ozone problems, we can make a big impact.

Robert Kent is director of environmental programs for the North Texas Commission.

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