87% of Earth's population lives where the air is toxic
Air pollution in China is getting a lot of press in recent times, especially with sad milestones like the first-ever smog 'Red Alert' in Beijing, but breathing clean air isn't just a dream for the Chinese. A new study published in the journal Environmental Science & Technology confirms, once again, sadly, that exposure to ambient air pollution is a global health crisis.
The researchers looked at areas where concentrations of tiny particulate matter in the air (PM2.5) exceeds limits set by the World Health Organization (WHO). By overlaying these areas (which you can see on the map below) with population density maps, they found that 87% of the world’s population lived in areas where the air is worse than what should be permitted according to WHO guidelines (using 2013 data, as it takes a while to gather global stats). China and India are in particularly bad shape, 0.4% of people in China and 0.01% in India living in areas meeting WHO levels.
Between 1990 and 2013, global population-weighted PM2.5 increased by 20.4%. In other words, the average person on Earth in 2013 was exposed to 1/5 more PM2.5 than in 1990. This was mostly driven by pollution increases in South Asia, Southeast Asia, and China.
But averages can be misleading, like with the man who drowned crossing a river that was just 3 feet deep on average... In richer countries, decreases in population-weighted concentrations of PM2.5 could be found. As you can see on the map, most of North-America isn't doing too bad on PM2.5 (though that doesn't mean that there's not air pollution or that things can't be even better.
The researchers also look at population-weighted concentrations of ozone pollution: Between 1990 and 2013, there was a global increase of 8.9%, with increases in most countries, except for some modest reductions in North America, parts of Europe, and several countries in Southeast Asia.
Here are some highlights from the findings:
"The highest concentrations of PM2.5 were evident in northern Africa and the Middle East due to emissions of windblown mineral dust; and in South and East Asia—especially in northern India and eastern China—due to combustion emissions from multiple sources including household solid fuel use, coal fired power plant emissions, landscape fires, industrial and transportation-related emissions."
"35% of global population resided in areas with concentrations above the WHO Interim Target 1 of 35 μg/m3 annual average PM2.5 with nearly all of the most extreme (>65 μg/m3) concentrations experienced by populations in China and India."
"Large relative increases [in estimated PM2.5 concentrations] were apparent in Western Canada, parts of South America, the Middle East, India and China. Somewhat similar patterns were also evident for ozone."