Clean Air and Global Health

Cleaner air, longer lives: Quantifying how air pollution impacts life expectancy

We develop the first systematic estimates of how air pollution shortens life expectancy around the world, taking advantage of a consistent global dataset. The impact of air pollution on human life spans around the world is strikingly large.

[Open Access Journal Article] | [NY Times Article

Citation: Apte JS, Brauer M, Cohen AJ, Ezzati M, Pope CA III. 2018. Ambient PM2.5 reduces global and regional life expectancy. Accepted, Environmental Science and Technology Letters.

Ambient air pollution is a major risk for premature death, killing more than 4 million people worldwide in 2016. While this risk is well understood, few studies to date have systematically evaluated how air pollution shortens lives around the world. We used detailed global data on death-by-age from the Global Burden of Disease 2016 study to quantify how fine particulate matter (PM2.5) air pollution reduces life expectancy at birth (LE) for 185 countries.
We found that the average human loses 1 year of life expectancy because of outdoor PM2.5 air pollution. Exposure to air pollution varies dramatically around the world, and there is generally a larger decline in life expectancy in more polluted countries. In especially polluted countries in Asia and Africa, people die on average 1.5-1.8 years early because of outdoor air pollution. Even in cleaner countries like the USA, current PM2.5 air pollution shortens lifespans by about 0.4 years.
The life expectancy impact of air pollution is large even relative to the impact of many other diseases that are more widely appreciated for their health risks. For example, removing air pollution as a risk for mortality would have a larger impact on lifespans than if major types of cancer — like breast cancer or lung cancer — were completely cured. In some polluted countries, air pollution does more to shorten life expectancy than all types of cancer combined.
The good news is that cleaner air can help bring about longer lives — a finding that has been repeatedly demonstrated through careful analyses around the world. Based on our models, we estimate that meeting the World Health Organization guidelines for PM2.5 air quality globally would lengthen the average human life by about 0.6 years overall, and by more than a year in the most polluted parts of Asia and Africa. Because air pollution has important risks even under the cleanest conditions, even countries that meet the WHO air quality targets could benefit from further improvements in air quality.
Many developing countries face two simultaneous risks from air pollution: on one hand, the outdoor air pollution often associated with industrialization and economic development, and on the other hand, high levels of indoor air pollution from cooking and heating with solid fuels like wood. The combined effect of indoor and outdoor air pollution on life expectancy is very large in places like India, Pakistan, and Bangladesh, where the average life is shortened by more than 2.5 years from the combined result of indoor and outdoor air pollution. In Sub-Saharan Africa, household air pollution has a larger impact on life expectancy than does outdoor air pollution.

Earlier research: Addressing Global Mortality from PM2.5

Journal article: Apte JS, Marshall JD, Cohen AJ, Brauer M. 2015. Adressing global mortality from PM2.5. Environmental Science & Technology, 2015 [open access]

Resources: Press release | High-resolution maps of mortality from PM (PDF, TIFF)

Ambient fine particulate matter (PM2.5) is the seventh-largest global risk factor for premature mortality, resulting in 3.2 million annual deaths in year-2010. To characterize how improvements in ambient PM air quality could result in improved health worldwide, we develop a high-resolution (10-km) model using data and methods from the 2010 Global Burden of Disease (GBD) study. The model combines fine-scale estimates of ambient PM concentrations with regional-cause specific mortality datasets and non-linear integrated exposure-response functions that describe the relationship between PM2.5 and mortality risks.

Improving outdoor air quality — in clean places and in polluted places alike — could potentially avoid millions of worldwide deaths each year. Meeting the WHO 2.5 air quality guideline concentration of 10 µg per cubic meter globaly could avoid up to 2.1 million annual deaths. One striking finding of this work is that comparatively small improvements in PM in already-clean locations (e.g, reductions of 1-4 µg per cubic meter in the U.S. and Europe) could avoid hundreds of thousands of annual deaths, while achieving comparable benefits in polluted developing countries (e.g., China, India) would require much larger improvements in air quality.  However, the potential health benefits of fully meeting WHO guidelines in China and India would be very large, avoiding roughly 1.4 million premature annual deaths from PM.