What do you think of when you hear the word “ozone?” For many of us, it brings to mind the early days of our cultural awareness about climate change. In the 1980s, scientists discovered a hole in the ozone layer. Ozone, we learned back then, is a gas floating in the stratosphere that helps protect us from the ultraviolet rays of the sun.
But it turns out there’s also a lower-altitude version of ozone. Armin Sorooshian is a professor who researches ozone at the University of Arizona, and he told The Show that this lower-altitude version of ozone is much less friendly.
Conversation
ARMIN SOROOSHIAN: Down low near the surface where we you and I everyone else where we're walking, living ozone has harmful effects because if we inhale it, it is an irritant, it's bad for our, our lungs. You know, it could lead to a coughing, scratchy throat could lead to long term effects like emphysema, chronic bronchitis, it could lead to asthma attacks.
SAM DINGMAN: Yeah. So part of the reason we're talking today is because the American Lung Association just released its state of the air report. And with that, there was the list of most polluted cities. Phoenix was number five on that list. And with one exception, New York, all of the other cities on that list, so 24 of, I believe the top 25, were either in the West or the Southwest. What is it about this region of the country that makes us so susceptible to this low altitude ozone that can get into our lungs?
SOROOSHIAN: So it really helps to know how you form ozone in the atmosphere. There's a few basic ingredients, you need sunlight and you need two other types of chemicals, which are referred to as precursor species and they are considered to be NOX, which is a, you know, fancy acronym that represents what we call nitrogen oxides. And then VOCs, which are volatile organic compounds. NOX and VOCs are emitted from all kinds of sources around us. It could be from human made activities like cars, industries or wildfires. And VOCs similarly can come from natural sources, too. Like one of the largest sources of VOCs is actually vegetation and then the fuel to really generate the ozone is sunlight. And so that's something we have a lot of, especially in the summertime and in the middle of the days here in the Southwest.
DINGMAN: You know, whenever I hear a story in the news about climate peril, I am tempted to ascribe the basis for that peril to people being irresponsible. Generally speaking, we're building too much, we're driving too much, we're using too many dangerous chemicals in our manufacturing, whatever the case may be. But if I'm hearing you right, while that may be playing some of a role here, the bigger factor is just that we live in a region that is uniquely predisposed to the formation of ozone.
SOROOSHIAN: That's right. That's right. And you know, if, if it was easy enough to just know what knobs to turn to reduce the ozone levels, it would have been done by now. It, it hopefully allows people listening to appreciate the complexity of ozone formation in big cities like Phoenix and Tucson, other ones across the Western U.S., it turns out on the weekend we have fewer people outside driving. So there's, there's less NOX emissions, but you might actually have higher ozone. This leads to the, the, the nonlinear factors leading to ozone, it turns out in, in big cities, if you have less pollution from things like vehicles, your ozone can actually go up. And in Phoenix, for instance, Sunday typically has the highest ozone and that's why it's so hard to know the best mitigation strategies right now to cut down the ozone. There's a lot of factors outside of our control.
DINGMAN: Well, you know, this is a more unnerving conversation than I was realizing it was going to be because again, you know, with a lot of climate stories, at least a lot of times in those conversations, you can come out feeling like, well, there there are things we could be doing. But this is pretty fascinating that ozone seems to be this phenomenon that behaves in such unpredictable ways that not only is it very dangerous but it is resistant to study because of its nonlinear or its volatile nature.
SOROOSHIAN: So we, we, our team at the UA, myself and another professor, Ave Arellano, we've been looking at all the archive data that we can find across the state of Arizona that's been collected over the last few decades and we're trying to use satellite data and advanced models. And so we've already been able to learn a little bit more about the temporal changes in ozone in different parts of Arizona across many years and looking at different seasons of the year, different days of the week, different times of the day.
And so we're making advancements and understanding, you know, when are the periods when ozone levels are the highest, which can help inform people like when are the times to avoid being outside, especially if you're vulnerable populations that are most vulnerable to ozone, are younger people, especially infants because their lungs are still developing, and elderly people. So some of the results we've already published on help provide these details of when are the worst times to be outside. And also, with all the modeling simulations we're doing, we're trying to advance our capabilities to forecast these sort of extreme ozone events.
DINGMAN: Is that the best course of action if it is a particularly bad day or period or region for ozone, is to just stay inside.
SOROOSHIAN: That is probably the best strategy because you wanna avoid breathing any of the air outside and you know, have good clean air in your homes, you know, with, with windows closed. That's probably a great strategy on the very high ozone days.
DINGMAN: So if somebody's listening to this and they're thinking to themselves, oh my God, I, I didn't even know that this was something I should be mindful of. I wonder if today is a bad ozone day. I'm outside right now as I'm listening to this, where do you recommend folks go to get an assessment of the current ozone levels and what actions they should take?
SOROOSHIAN: Yeah. So everyone walking outside, for instance, usually has a smartphone. And so, you know, if you just go to your weather app, or there's so many apps now, there's an air quality index value that is provided like for me right now, I'm looking at my phone, I'm looking at my weather app and there's an air quality index of 36 in Tucson as we speak, which is classified as good. The important thing to know is that again, it's been around forever and we're just only learning more about it because of our more advanced methods, which is only gonna help us in the future.
