Researchers have investigated the link between decreasing vehicle emissions and deaths attributable to air pollution.
Using recent national emissions data, researchers from Harvard Chan School’s Department of Environmental Health, modelled four scenarios for emissions in 2017. This consisted of actual emissions, and three alternative scenarios, in which county-level emissions were the same as they were in 2014, 2011 and 2008. Each scenario factored a variety of factors, such as, the type of vehicles being driven and how many miles they travelled, detailed data about air pollution levels across the US, mortality rates, and trends in demographics.
“Recent reductions in vehicle emissions have yielded major health benefits, even though only small progress has been made on reducing their climate impact,” said Choma, one of the authors of the study. “Our results indicate that to achieve further public health and climate gains, even more stringent policies will be required.” Thus, despite the air pollution improvement, the Earth’s climate is still suffering.
The researchers estimated that the deaths attributable to air pollution dropped from 27,700 in 2008 to 19,800 in 2017. This decrease was not as notable as scientists were expecting. This is due to a variety of factors that influenced the results, that were not accounted for. Thus, components such as a larger and aging population, larger vehicles replacing smaller ones, and more miles travelled per vehicle, were not taken into consideration when calculating this estimation. Although, when Choma and their team discovered that if vehicles were still emitting emissions as they were in 2008, 48,200 deaths would have occurred between 2017 and then, emitting a 74% increase.
Air pollution link implications
Significant progress was made in reducing the emissions contributing towards air pollution from heavy-duty trucks. However, there was not much success in doing the same with light-duty vehicles, such as cars, SUV’s and pickup trucks. Light duty vehicles account for two-thirds of the public health burden from transportation related air pollution in 2017. Researchers noted that emissions from these vehicles in large metropolitan areas are responsible for more than 30% more attributable deaths than all heavy-duty trucks combined.
The link between health, and the impact on climate change from vehicle emissions, has been widely studied in the US. It is because of research into this topic that federal air pollution regulations and technological innovations by car manufacturers were introduced. This study investigates how these policies have impacted vehicle emissions, and as a result, public health. The drop in deaths related to illnesses caused by vehicle emissions suggests that, while there is a notable drop in deaths, the Earth’s climate is still a long way from any notable benefits.
“If the trends of increased population density with an aging population, and a shift to larger passenger vehicles continue, emissions, especially in urban areas, will continue to become more harmful and it will be harder to achieve further public health gains by small incremental improvements in new vehicles,” said John Spengler, Akira Yamaguchi Professor of Environmental Health and Human Habitation and another author of the study. “Our study findings strengthen the case for policies at the municipal level that encourage electric vehicles while discouraging conventional gasoline vehicles and for making our cities more accessible for non-motorized transportation such as biking or walking.”
Choma and their team calculated the social benefits attributable to decreasing emissions and estimated that reductions in air pollution yielded 270 billion dollars in 2017. This is primarily due to the estimated value of reduced mortality risk from the particulate matter. Also, reduced social costs from greenhouse gas emissions were considered in the calculation, as this factor had a minor but notable impact.