Pollution Helps Kill 6.1 Million People Per Year, But Indoor Air Pollution is Decreasing

The annual State of Global Air Report published last week by the Health Effects Institute (HEI), a U.S. non-profit corporation funded by the EPA and the auto industry, found that over 95 percent of the world's population is breathing unhealthy air. Long-term exposure to outdoor and indoor air pollution contributed to the deaths of 6.1 million people globally in 2016, with strokes, heart attacks, lung disease and lung cancer responsible for most of these deaths.

According to the report, outdoor (ambient) air pollution from fine particles less than 2.5 micrometers in diameter (PM2.5) was responsible for 4.1 million deaths in 2016 (close to the 4.2 million deaths recorded in 2015), while indoor (household) air pollution from PM2.5, due to burning solid fuels indoors, was responsible for 2.6 million deaths (down 9% from 2.85 million deaths in 2015). Some of these deaths were due to a combination of both indoor and outdoor air pollution. Ground-level ozone, the other key deadly outdoor air pollutant, whose levels are on the rise around the world, was blamed for 234,000 air pollution deaths, an 8% decrease from the 254,000 ozone-related deaths in 2015.

Air pollution is the fourth-highest cause of death worldwide, trailing smoking, high blood pressure and diet. The majority of air pollution deaths are in poor countries. India and China lead the world in the total number of deaths attributable to air pollution in 2016 with 1.61 and 1.58 million, respectively. Air pollution killed 105,000 people in the U.S. in 2016, with 93,000 of those deaths due to PM2.5; 12,000 deaths were blamed on ozone pollution (see the HEI’s interactive plots to graph pollution levels and deaths by country).

Figure 1. Proportion of the population subjected to indoor air pollution due to the burning of solid fuels for cooking or heating, 1990 – 2016.

A success story: the number of people exposed to indoor air pollution is dropping

While the death toll and numbers of people exposed to unhealthy levels of outdoor air pollution have not changed much in recent years, there was one significant success story to report: the total number of people exposed to indoor (household) air pollution through burning solid fuels has been dropping in recent years, despite significant global population growth. People in developing nations routinely use wood, hay, dung, charcoal or coal to fuel inefficient, smoke-belching indoor cookstoves that emit high quantities of dangerous fine particles. The total number of people using solid fuels indoors fell from just over 3 billion in 1990 to about 2.4 billion (34% of the world’s population) in 2016. According to Forbes, India in particular has had great success combatting indoor air pollution by expanding and modernizing its electricity network, and by providing liquefied petroleum gas (LPG) as a cooking fuel.

However, in East, Central, and West sub-Saharan Africa, where the percentages of population exposed to indoor air pollution have been the highest, there has been little change in exposure. Nigeria, Ethiopia, the Democratic Republic of Congo and Tanzania have all seen net increases in populations exposed to indoor air pollution in recent years.

Figure 2. Costs and benefits of the Clean Power Plan as estimated by the U.S. EPA. Image credit: U.S. EPA.

Yearly costs of air pollution: $5.1 trillion globally, $473 billion in the U.S.

The 2018 HEI report did not attempt to estimate the costs of air pollution to the global economy, but instead referred readers to a 2016 report by the World Bank.  That report estimated that in 2013, the most recent year full data was available, exposure to outdoor and indoor air pollution cost the world’s economy $5.11 trillion in welfare losses. These losses were highest in South Asia, East Asia and the Pacific: 7.4 - 7.5% of the regional gross domestic product (GDP). The report estimated that the U.S. suffered $473 billion in health-related damages from air pollution in 2013 (2.9% of the GDP). Health care consumes one-quarter of the $3.7 trillion U.S. federal budget, and air pollution is a major reason why.

Unfortunately, the Trump administration has taken steps that will greatly limit the ability of the U.S. to reduce this massive cost in lives and dollars. As I blogged about last year, the administration is withdrawing from the Paris Agreement to limit global greenhouse gas emissions, and is attempting to scuttle the Clean Power Plan, the key feature of the U.S.’s Paris climate accord commitment. Burning fewer fossil fuels creates less air pollution, and air pollution from the power generation industry will fall about 25% by 2030 if the Clean Power Plan is adopted. The EPA projects that the reduction in pollution will prevent up to 3,600 deaths, 1,700 heart attacks, 90,000 asthma attacks in children, and 300,000 missed work and school days per year by 2030 (note that a person who dies from air pollution-related causes typically dies about twelve years earlier than they otherwise might have, according to Caiazzo et al., 2013). For every dollar Americans spend on the Clean Power Plan, $4 worth of health benefits will result, says the EPA.

Have a great weekend, everyone!