Web Date: January 15, 2016
Estimating Damages And Deaths From The Volkwagen Emissions Scandal
Last year, the news broke that in the U.S. almost 600,000 Volkswagen diesel vehicles, model years 2009 to 2015, contain software that altered engine performance and lowered emissions of toxic nitrogen oxides (NOx) during emissions tests but not during normal driving. U.S. regulators have now filed a federal lawsuit against the automaker alleging violations of the Clean Air Act. In the atmosphere, NOx produces particulate matter and ground-level ozone, which aggravate heart and lung disease. A new study calculates the societal impact of this extra NOx: 46 excess expected deaths and $430 million in excess damages (Environ. Sci. Technol. 2015 DOI: 10.1021/acs.est.5b05190).
This work makes the consequences of VW’s actions more real and personal, says Ray Minjares, who works on health impact assessments for motor vehicles at the International Council on Clean Transportation (ICCT). He was not involved with the current study, though research supported by ICCT first revealed the excess emissions from VW vehicles.
Other automaker scandals, like General Motors’ defective ignition switch in 2014 and a Bridgestone/Firestone tire recall in 2000, caused accidents that led to deaths. In contrast, the impact of excess NOx emissions is invisible, as it’s impossible to identify specific people affected by the pollution, says Andrew Yates, an environmental economist at University of North Carolina, Chapel Hill.
To calculate damages and deaths from the VW scandal, Yates and his colleagues first estimated where the altered cars were located in the U.S., how far they were driven, and how much NOx these cars emitted in excess of limits set by the Environmental Protection Agency.
To do this, the researchers contacted a market research firm to obtain the county-by-county locations of 447,549 altered cars registered in the U.S. through June 2015. Then, they used data from the Federal Highway Administration to determine how far, on average, a typical vehicle in each of the affected model years was driven in each state. Finally, they estimated the amount of excess NOx produced by the altered cars using emissions measurements gathered from two different VW vehicles under actual driving conditions by researchers at West Virginia University as part of the tests that uncovered the scandal.
The researchers combined this information to estimate the excess NOx emissions in each county and used a model to predict the impact of air pollution by county. The model describes pollution movement through the atmosphere, tracks how NOx changes into harmful ozone and particulates, and predicts the health consequences and monetary damages from that pollution. The damages—primarily from particulate matter—include deaths, illnesses related to air pollution, reduced agricultural yield, degradation of buildings, reduced visibility, and reduced recreation. The model assigns costs to each of these to determine the monetary damages from NOx emissions.
The researchers found that the largest damages did not correspond to the regions with the largest number of affected vehicle registrations. For example, Minneapolis has the largest damages, even though the area ranks 14th in number of registered affected cars. Washington, D.C., on the other hand, ranks 28th in terms of damages, but third for registrations. The researchers think this is because atmospheric ammonia is required for the NOx reaction that forms particulate matter, and agricultural areas, such as those near Minneapolis, tend to have higher levels of atmospheric ammonia.
A previous study predicted 59 excess premature deaths and $450 million in societal costs from the scandal (Environ. Res. Lett. 2015, DOI: 10.1088/1748-9326/10/11/114005). Minjares is pleased that the estimates from the two studies are so similar, even though the studies used different air pollution models and data for vehicle activity and location. The similarity gives valuable robustness to the estimates, he says.
The two studies use also use an approach similar to the one that government regulators use to estimate benefits and costs of regulations, Minjares adds. “It’s a fairly well understood and trusted approach to estimating impacts.” That speaks to regulators and government officials seeking to understand the magnitude of the impacts from the scandal, he says.
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