Wildfire smoke: How bad is air pollution for your health?

As wildfires rage across the Northern Hemisphere, many people are wondering how the smoky air might affect their health.  

Air pollution: A major risk factor for illness and death

People are right to worry. Air pollution is a major contributor to health problems globally. According to the Global Burden of Disease Study, air pollution is the fourth-leading risk factor for early death and disability worldwide, ranking just below tobacco (#3) and higher than alcohol use (#9). While wildfires can produce air pollution, and killed an estimated 130,000 people worldwide in 2019, there are more mundane kinds of bad air that people are exposed to daily that can also cause health problems.  

Read more in Think Global Health: Protecting Ourselves from Wildfire Smoke

Infants have the highest rates of death from air pollution

According to the Global Burden of Disease study led by IHME, when looking at deaths linked to air pollution across age groups, newborn babies ages 0 to 6 days old have high rates of death. Other people at higher risk of death from air pollution include slightly older newborns (infants ages 7 to 27 days) and older adults. This is because air pollution contributes to low birthweight and preterm births, which make infants more vulnerable to infectious diseases and long-term disability. At the same time, some conditions associated with pollution exposure take many years to develop, like chronic obstructive pulmonary disease (COPD), which includes emphysema. These air-pollution-related deaths will therefore only be associated with adults.

Countries in Asia, Africa, and the Middle East are most affected by air pollution

The State of Global Air 2020 report, which is produced jointly by the Health Effects Institute and IHME, found that the countries with the highest average annual exposures to ambient air pollution in the last decade were India, Nepal, Niger, Qatar, Nigeria, Egypt, Mauritania, Cameroon, Bangladesh, and Pakistan. People in South Asia were consistently the most exposed, and countries with some of the highest exposures in the world—such as India, Pakistan, and Bangladesh—continue to see increases in exposure. Higher air pollution levels are associated with lower levels of income because burning solid fuels (such as coal and wood) tends to be less expensive than burning liquid fuels (including propane and natural gas) or using renewable energy, but generates more air pollution. The degree of pollution in the air also depends on whether or not a country has taken meaningful steps to reduce pollution through national policy. For example, between 2013 and 2017, China implemented a five-year plan to improve air quality and saw ambient pollution levels drop by 30%. 

Air pollution trends vary by a country’s level of income

While 90% of the world experienced pollution levels that exceeded WHO’s Air Quality Guidelines in 2019, higher-income countries tended to have cleaner air than lower-income countries. Progress toward improving disparities in air quality stalled over the last decade, but there is one area of marked improvement: household air pollution, which is mostly caused by cooking with solid fuels. People in lower-income countries tend to use solid fuels more often than people in higher-income countries. In places like India and China, which waged campaigns to shift people away from using solid cooking fuels, household air pollution and the mortality associated with it declined. In fact, the largest decline in the burden of disease from air pollution was associated with introducing cleaner cooking fuels.