A new study provides the most detailed picture available to date of the global, regional, and local health impacts attributable to emissions from four transportation subsectors: on-road diesel vehicles; other on-road vehicles; shipping; and non-road mobile engines such as agricultural and construction equipment.

Transportation-attributable PM_2.5 and ozone deaths, associated mortality rates, and population in G20 economies in 2015. Source: The ICCT.

The study, by researchers from the International Council on Clean Transportation (ICCT); George Washington University Milken Institute School of Public Health; and the University of Colorado Boulder, links state-of-the-art vehicle emissions, air pollution, and epidemiological models to estimate health impacts at the global, regional, national, and local levels in 2010 and 2015.

The study links vehicle tailpipe emissions to ~361,000 premature deaths from ambient PM_2.5 and ozone worldwide in 2010 and ~385,000 in 2015, equivalent to 11.7% of global ambient PM_2.5 and ozone premature deaths in 2010 and 11.4% in 2015.

An estimated 84% of global transportation-attributable deaths occurred in G20 countries, and 70% occurred in the four largest vehicle markets in 2015: China, India, the European Union, and the United States.

Exhaust from on-road diesel vehicles was responsible for nearly half of the impacts (~181,000 premature deaths) worldwide, and fully two-thirds in India, France, Germany, and Italy.

Together, PM_2.5 and ozone concentrations from transportation emissions resulted in 7.8 million years of life lost and approximately $1 trillion (2015 US$) in health damages globally in 2015.

The urban areas with the highest number of transportation-attributable air pollution in 2015 were Guangzhou, Tokyo, Shanghai, Mexico City, Cairo, New Delhi, Moscow, Beijing, London, and Los Angeles. By contrast, when normalized by population, the urban areas with the highest number of transportation-attributable air pollution deaths per 100,000 people were Milan, Turin, Stuttgart, Kiev, Cologne, Haarlem, Berlin, Rotterdam, London, and Leeds.

The global health burden of on-road diesel vehicles, including the PM_2.5 and ozone impacts of all tailpipe emissions, is 68% higher than previously estimated for diesel NO_x emissions, because it includes the effects of tailpipe PM_2.5.

The distribution of health impacts and air pollution from transportation is influenced by policy, demographic, economic, and technological changes.

Transportation-attributable health impacts declined in the United States, European Union, and Japan as vehicle emission standards have been implemented, but these reductions have been offset by growing impacts in China, India, and other parts of the world. Unless the pace of transportation emission reductions is accelerated, these health impacts are likely to increase in the future as the population grows, ages, and becomes more urbanized.

—Susan Anenberg, lead author of the study and an associate professor at the George Washington University Milken Institute School of Public Health

The high public health burden of diesel vehicles in Europe underscores the need for world-class emissions standards to be accompanied by robust compliance and enforcement. The long lifetime of vehicles and equipment and the increasing health burden in regions without adequate protections stress the urgency to introduce world-class standards, develop compliance programs, and adopt in-use measures that accelerate the replacement of high-emitting vehicles.

—Joshua Miller, co-author of the study and a senior researcher at the ICCT

Ambient air pollution is the leading environmental health risk factor worldwide, contributing to 3.4 million premature deaths annually from heart and lung diseases and diabetes, according to the Global Burden of Disease (GBD) study 2017. Previous studies had estimated the global health burden of emissions from all transportation sources, and from subsectors such as land transportation and shipping, in 2005, 2010, and 2014, but none had evaluated health impacts at the same level of granularity as this study.

The study assessed health impacts of transportation emissions using the GBD 2017 methods, which consider the impacts of ambient PM_2.5 and ozone exposure on incidence of six disease categories. Those methods do not quantify the direct health impacts of nitrogen dioxide (NO₂) exposure, which is associated with asthma incidence among children worldwide and asthma emergency department visits.

Globally and for each trade bloc, transportation-attributable fractions (TAF) of combined PM_2.5 and ozone deaths in 2015, broken out by subsector. AMU = Arab Maghreb Union (North Africa); ASEAN = Association of Southeast Asian Nations; CARICOM = Caribbean Community; CEMAC = Central African Economic and Monetary Community; CIS = Commonwealth of Independent States; EAC = East African Community; ECOWAS = Economic Community of West African States; EU & EFTA = European Union and European Free Trade Association; GCC = Gulf Cooperation Council; MERCOSUR = Southern Common Market (South America); NAFTA = North American Free Trade Agreement; SAARC = South Asian Association for Regional Cooperation; SADC = Southern African Development Community; SICA = Central American Integration System. Source: The ICCT.

However, NO₂ is a precursor to both PM_2.5 (in the form of nitrate aerosols) and ozone levels, so policies that target reductions in NO₂—for which many European cities exceed EU air quality standards—would reduce the incidence of premature deaths from ambient PM_2.5 and ozone, the health endpoints that were quantified for 2010 and 2015 in this study.

Recent evidence indicates that the health response to PM_2.5 pollution may be greater at high concentrations than previously estimated, and that air pollution may be associated with chronic kidney disease, preterm birth and other birth outcomes, and cognitive decline. Consideration of these impacts would likely increase the estimate of health impacts from vehicle exhaust emissions.

Resources

• Susan Anenberg, Joshua Miller, Daven Henze, Ray Minjares (2019) “A global snapshot of the air pollution-related health impacts of transportation sector emissions in 2010 and 2015” International Council on Clean Transportation