Air pollution is deadly, a new study has confirmed.
The study, published this week in Nature, found that outdoor air pollution kills 3.3 million people around the world every year. And that number is set to rise in the next 35 years — if worldwide emissions continue unabated, the number of deaths caused by air pollution each year could double to 6.6 million by 2050.
“This projection should sound alarm bells for public-health agencies around the world,” Michael Jerrett, professor and chair of the Department of Environmental Health Sciences at UCLA, wrote in a letter accompanying the study.
The study found that China and India — the world’s first- and third-highest greenhouse gas emitters — have the highest rates of death from air pollution. In China, a country that’s suffered from off-the-charts air pollution that’s closed schools and forced some residents to stay indoors, air pollution kills nearly 1.4 million people each year. India — which is home to Delhi, a city which has the most toxic air of any city in the world — sees about 645,000 deaths due to air pollution every year. In the United States, according to the study, air pollution kills about 54,900 people annually.
The main causes of air pollution-related death are cerebrovascular disease (which affects blood flow to the brain), certain forms of heart disease, and chronic obstructive pulmonary disease (COPD). Residential and commercial energy use — which includes burning things like coal and wood on a small scale and using diesel for fuel — contributes most to deadly outdoor air pollution worldwide. The second-largest contributor to dangerous air pollution is, surprisingly, agriculture — the study found that ammonia released from fertilizer and animal waste reacted with traffic and power plant fumes to create dangerous particulate matter. In the United Kingdom, nearly half of all pollution-related deaths are tied to agricultural pollution, according to the study.
The study only looked at outdoor air pollution — meaning the total number of deaths from air pollution worldwide is even higher than 3.3 million. According to the study, indoor cooking and heating causes an estimated 3.54 million deaths each year.
Other studies have quantified the death tolls and health impacts from air pollution, but this one is one of the most detailed to date. The World Health Organization reported in 2014 that air pollution kills 7 million people each year — a number that roughly lines up with the total deaths caused by indoor and outdoor air pollution cited in the Nature study. A study from last month found that 17 percent of all China’s deaths are related to the country’s air pollution. And a major report published in June in The Lancet sounded the alarm on air pollution and climate change’s deadly impacts — high temperatures drive up ground-level ozone, pollution that can damage lungs.