Highway Vehicles Responsible for a Declining Share of Pollutants
October 9, 2017
Over half of all carbon monoxide (CO) emissions in 2002 were from highway vehicles; by 2016 that fell to 30%. The share of nitrogen oxides (NOx) emissions from highway vehicles declined from 43% of all NOx emissions in 2002 to 34% in 2016. The highway share of volatile organic compound (VOC) emissions declined by 9% during this same period. Highway vehicles contributed less than 3% of all particulate matter (PM) emissions.
Highway Vehicle Share of U.S. Air Pollutant Emissions, 2002–2016
Note
Particulate matter emissions include both fine particle matter less than 10 microns (PM-10) and fine particle matter less than 2.5 microns (PM-2.5).
Source
U.S. Environmental Protection Agency, National Emissions Inventory and Air Pollutant Emissions Trends Data.