By David Fertitta
From 2009-2015, Volkswagen has been installing devices in certain vehicles designed to recognize when the vehicle was being tested to make sure it complied with U.S. Environmental Protection Agency (EPA) emission standards. Once the device software detected that the vehicle was being tested, the engine switched to a calibration that met the EPA emissions standards. However, when not in testing, the engine switched to a different calibration that would be used in normal driving. The EPA notice of violation of the Clean Air Act mentions that this reduced the effectiveness of the emission control system and that “emissions of [nitrogen oxides] increased by a factor of 10 to 40 times above the EPA compliant levels” for certain models of Volkswagen’s 2.0-liter diesel engine vehicles that were equipped with these “defeat devices.”
But what do the excess levels of nitrogen oxides mean for your health?
To understand how an increase in nitrogen oxides could affect people’s health, I spoke with Dr. Vince Wilson, a toxicology professor in the LSU Department of Environmental Sciences.
“When they say nitrogen oxides, it’s really nitric oxide (NO) and nitrogen dioxide (NO2),” Wilson said. He explained that these two molecules get involved with chemical reactions in the atmosphere that can lead to problems associated with ozone and smog. An accumulation of nitrogen oxides in the atmosphere can also react with water and lead to a buildup of nitric acid, which contributes to acid rain.
Nitrogen dioxide and nitric oxide
Nitrogen dioxide is a pulmonary irritant and as its concentration in the atmosphere increases, people may start to get watery eyes, scratchy throats, and other irritations in their upper respiratory tract.
However, nitrogen dioxide can undergo several reactions in the atmosphere, so the more nitrogen oxides that are being put into the air, the worse the air quality is. In the presence of UV light from the sun, nitrogen dioxide can react with oxygen to create ozone in the air we breathe which can cause a host of other health problems.
Wilson also discussed the reactive nature of nitrogen oxides with volatile organic compounds (VOCs), carbon-containing compounds that are often emitted to the atmosphere from the burning of fossil fuels and vegetation. “These VOCs will react with UV light and various compounds including nitrogen dioxide,” he said, “and you end up with aldehydes which are toxic.”
“For nitric oxide, the concentration is usually low enough that it’s not a problem,” Wilson said, “but it can be toxic at high levels.” He also said the nitric oxide is very reactive in the atmosphere. “This leads to more ozone produced at ambient breathing level instead of the upper atmosphere where we want it,” he said. Ozone at this level contributes to poor air quality and can affect our lungs.
Levels of nitrogen oxides are so critical for air quality measures that nitrogen dioxide is one of the compounds constantly being monitored in our air under the Louisiana Department of Environmental Quality (DEQ) Ambient Air Monitoring program. “There are 6 stations around East Baton Rouge Parish that monitor for these compounds,” Wilson said. “[For] one of my master’s students, part of her project was collecting all that information and correlating it with health.”
EPA standards exist to regulate emissions of nitrogen oxides, a byproduct of combustion, in order to ensure clean air and a healthy population. While the increase in levels of nitrogen oxide emissions can create enough health problems on their own, the reactive nature of nitrogen dioxide and nitric oxide can also lead to a host of other environmental problems associated with air quality that can directly affect people’s health and well-being. When Volkswagen installed these defeat devices, they directly bypassed EPA emission standards, which could lead to detrimental issues associated with people’s health.