Editor's note: This Signature Story is part of the NET News QUEST Nebraska project, a multimedia series exploring Nebraska science, environment and nature. It's a common summer scene.
Vehicle traffic in most places, including the Omaha metro area picks up when the temperature rises. Vacations, more daylight and other factors put more people on the road. With or without the traffic, summer heat is sometimes described as stifling. There might be some truth to that. As traffic planner with the Metropolitan Area Planning Agency (MAPA), Sloan Dawson says something happens when mixing heat and traffic emissions.
"Those are things sort of beyond our control. Heat, humidity, intensity of sunlight. And of course, you know, winds. But uh, you know, the problem is sort of ozone formation is at its highest in typically the hotter parts of the day and particularly in the summer. Because it intense heat, intense sunlight really are the catalysts for the chemical reactions that essentially cause oxides of nitrogen and VOCs to form ozone molecules."
Click here for a video about ozone levels in Omaha, and how new EPA regulations could affect the city.
VOCs are volatile organic compounds. Some of the bad stuff associated with something called ground level ozone. It's expected that the Environmental Protection Agency will release new acceptable levels for ozone in the atmosphere in the next week. While it's not known exactly what the standard will be, it is known that the city of Omaha will be very close to it.
Ozone at higher altitudes is a good thing. It's the same chemical composition but provides a protective layer for the earth's atmosphere from the sun's harmful rays. But high amounts of ground level ozone create problems for people with respiratory and other health conditions particularly the very young and very old. That's one reason the Environmental Protection Agency is expected to lower the acceptable amount of ground level ozone. Dawson says the number the EPA decides on, will likely determine if Omaha is above or below the limit.
"The current standard is set in the mid-70s and that's measured in parts per billion and based on eight-hour average. So there are a lot of sort of statistical and mathematical controls that they have in place to really ensure that the measurement's as fair as possible, we're sort of in the mid 60s in this figure and the new range that the EPA's considering is between 60 and 70 parts per billion. So we're really kind of on the cusp of a potential new standard. And that announcement is actually supposed to come in late July."
The Nebraska Department of Environmental Quality is working with Omaha on the issue. DEQ is responsible for complying with EPA standards. Ground level ozone is a tricky pollutant to address. Brian Kozisek is with the Air Quality Division of DEQ.
"If you're finding lead emission in the air you're only going to have a few places that you know you're going to look at, but, with this it could be coming from anywhere so that does make it more difficult and adding to the problem is that ground level ozone actually may not form where the emissions are coming from so it may be forming miles away from where those emissions are so in that area you may see really low ozone readings but they may be higher someplace else and that's really the situation we ran into with what we're looking at right now."
There are three ground level ozone monitors in Omaha that have shown the city could be on the cusp of the new standard. But it's a metro area monitor about 40 miles away that's had the highest readings. It's in a small two-wheeled trailer, parked in rural Harrison County, Iowa that is telling Air Quality Standard officials like Kozisek, there's a potential problem.
"Now that monitor is run by the Iowa Department of Natural Resources but it was specifically set up to help to check the Omaha metropolitan area ozone levels and so I haven't been up to the monitor but from what I've been told is you're looking at the Pisgah hills run on the east side of it to where the monitors sits so there's some people that think that some of those emissions might be getting kind of stuck in that hilly area, you know, which could be but regardless it's going to be the, you know, the numbers are there, you know so we do know that the pollution is going there. There's been already some preliminary work done by the EPA in looking at prevailing winds to see how - what major sources of nitrogen oxides and VOC's in our area, where their emissions are ending up at and a lot of it has been pointing right towards Pisgah so it's a pretty safe bet that they're reading levels are going to be due to the Omaha metropolitan area."
Harrison, two other Iowa counties and five Nebraska counties are part of MAPA. It's working with Nebraska DEQ to address the issue whether or not Omaha is above or below the new limit. The business community is involved to identify best practices for reducing emissions, but for MAPA's Dawson, it starts with vehicles.
"Ground level ozone to a transportation planner is a potential obstacle. Since travel generates a lot of the precursor missions to ozone primarily oxides of nitrogen and volatile organic compounds, transportation is sort of a central concern when remediating or addressing an ozone problem. And we are sort of experiencing or at the beginning of experiencing on issues with those on air quality in our regions. So that naturally has some impact on the transportation system on and we're trying right now really to work on voluntary efforts on through encouraging car polling, on active transportation like bicycling and taking transit to really sort of mitigate some of those impacts."
Those are the types of things we've been hearing about for a while to help reduce automobile pollution. But MAPAs making it a public information campaign and Dawson says there are other things private citizens can do to limit ground level ozone. It goes back to how the heat of summer, even the hotter part of the day, encourages the pollutant to increase.
"Filling up a gas tank after 7 PM. I know it sounds a bit counter-intuitive, but there's a substantial difference in the amount of gasoline lost to evaporation between 90 or a hundred degrees and 70 degrees even. And this can aggregate over time.
"Not topping off your gas tank for similar reasons, the evaporative loss of the gasoline. And also not idling. So if you're somewhere for, you know, more than 30 seconds, turn off your car and that really helps out a lot. Also not mowing during the peak heat of the day. So mowing on the weekends, mowing in the evenings, really can make a substantial difference as well."
The campaign is called Little Steps, Big Impact . It's voluntary right now, but could take increased importance if Omaha exceeds the new standard the EPA sets. In the mean time, Dawson says, everyone in Omaha can help.
"The idea that each and every one of us does, you know, makes these small modifications to our behavior, that over time, the impact on the issue of the air quality is substantial."
They'll be no fines or penalties initially if Omaha exceeds the new allowable limit for ground level ozone. If that happens, DEQ and others would be required to establish an action plan within three years to address it.