Nitrogen oxides such as NOx is along with COx a major constituent of tailpipe emissions, and a study of European historical data suggests the proportion of NO2 in NOx emissions is smaller than previously thought.
Legislation in Europe sets emission standards according to pollutant level inventories. These limits, in turn, have an impact on the industry in general and in transportation specifically, in the production management strategies and the engineering control devices to minimize emissions.
(Phys.org)—A team of researchers at the University of York analyzed the data from roadside air quality monitors located in urban areas across 61 cities in Europe and found that the proportion of nitrogen dioxide (NO2) in nitrogen oxides in European traffic emissions is smaller than has been thought.
Study Findings Implications
In their paper in the journal Nature Geoscience, they provide analysis of data from roadside monitors over the years 1990 to 2015. Drew Gentner and Fulizi Xiong with Yale University offer a News and Views perspective on the work done by the team in the same journal issue and suggest that the team’s findings could have implications for air pollution standards organizations in many more places than just Europe.
According to the study, the data gathered shows a drop in NO2 down to a level where it remained constant after car and truck owners made the switch from gasoline to cheaper diesel-powered vehicles. Now, the regulations enacted by European governments aimed at limiting NO2 emissions, not taking into account that NOx will undergo changes once emitted and turned into NO2.
Furthermore, the regulations limit NO2 as a proportion or percentage to NOx, so the actual levels of NO2 are actually smaller. Therefore, standard based NO2 emission levels could be reached sooner than expected with the ease of expected impacts on health and environment throughout Europe.