Global population exposed to fine particulate pollution by population increase and pollution expansion

Abstract

Ambient fine particulate (PM2.5) pollution threatens public health. Previous studies have primarily focused on PM2.5 estimation, with the quantitative analysis of public exposure and the reason for increased risk receiving limited attention. Quantitative information is essential for environmental risk estimation. Thus, we collected PM2.5 data and population records to illustrate the spatiotemporal patterns of PM2.5 pollution and to quantify public vulnerability and the cause of increased exposure at global, regional, and country scales from 2000 to 2010, following the air quality standards of the World Health Organization. We found that 11.0 × 106 km2 (8%) of the global terrestrial area was exposed to PM2.5 pollution (> 35 μg/m3) in 2010, an addition of 4.3 × 106 km2 since 2000. Furthermore, by 2010, 1.94 billion (30%) people worldwide were exposed to PM2.5 pollution, including 966 and 778 million in Eastern and Southern Asia, respectively, comprising 962 million in China and 543 million in India. After 2000, the vulnerability of 698 million people to PM2.5 pollution increased, including 356 and 280 million in Southern and Eastern Asia, respectively, accounting for 279 million in China and 253 million in India. Moreover, 25% of the global vulnerability increase was from local population growth, and 75% was due to pollution expansion. Specifically, 26 and 16% of the increase in public vulnerability in Southern and Eastern Asia (22 and 16% in India and China), respectively, were from local population growth. We suggest that countries in which migration has contributed to an increase in public vulnerability should balance pollutant emission reduction and migration control to reduce vulnerability. In addition, cooperation between the government and public could help mitigate global pollution as well as environmental and human health risks.