Emissions testing of vehicles has increased considerably over the past few decades. Though many people get frustrated with the requirements for their cars to pass emissions inspections, these regulations are saving lives. Air pollution from vehicle emissions is directly related to air quality and the health of people breathing in those pollutants. Air quality in the US and Europe has improved drastically since their poor historical conditions. In the US, vehicle emissions have been drastically reduced by as much as 99% per vehicle since 1970.
A new study assessed the impacts of vehicle emission reductions from 2008 to 2017, reporting huge benefits from reduced mortality from air pollution and a reduction in greenhouse gas emissions. In 2008, 27,700 deaths were attributed to air pollution from vehicle emissions. If emissions stayed the same, 48,200 deaths would have been expected in 2017. But 2017 only saw 19,800 deaths because of the improvements in vehicle emissions. This decrease in expected deaths is still not as profound as it could have been, as there were more cars on the road and more total miles driven than in 2008.
Breaking it down by vehicle type, Heavy Duty Transport, or large trucks like 18-wheelers, accounted for much of the improvement. Without emissions improvements, heavy-duty transport vehicles would have had 3.4x as many emissions. Light-duty Vehicles, aka passenger cars, contributed some improvement, but only would have been twice as bad without emission improvements. While only 28% of Greenhouse gas emissions come from transportation, 58% of transportation greenhouse gasses come from light-duty vehicles, and this percentage is increasing. Passenger vehicles are getting larger, and they are being driven more miles, so despite emission efficiency improvements, passenger vehicles are responsible for more PM2.5 deaths than large trucks.
Looking at the locations of vehicle pollution, there are large differences across states and cities. Some pollutants are very local and tend to cause problems in the cities where they are emitted, while other pollutants, like SO2, NOx, NH3, and VOCs, add to gaseous air pollution and waft across state lines.
In dollars, the EPA has estimated that the Clean Air Act Amendments of 1990 have provided two trillion USD per year in benefits. That’s thirty times the cost of implementing the amendments, and 90% of those benefits were calculated from reduced mortality.