PM2.5 air pollution, population exposed to levels exceeding WHO guideline value (% of total)
Definition: Percent of population exposed to ambient concentrations of PM2.5 that exceed the WHO guideline value is defined as the portion of a country’s population living in places where mean annual concentrations of PM2.5 are greater than 10 micrograms per cubic meter, the guideline value recommended by the World Health Organization as the lower end of the range of concentrations over which adverse health effects due to PM2.5 exposure have been observed.
Description: The map below shows how PM2.5 air pollution, population exposed to levels exceeding WHO guideline value (% of total) varies by country. The shade of the country corresponds to the magnitude of the indicator. The darker the shade, the higher the value. The country with the highest value in the world is Mali, with a value of 100.00. The country with the lowest value in the world is Kiribati, with a value of 0.00.
Source: Brauer, M. et al. 2016. “Ambient Air Pollution Exposure Estimation for the Global Burden of Disease 2013.” Environmental Science & Technology 50, no. 1: 79–88.
Development Relevance: Air pollution places a major burden on world health. More than 40 percent of the world’s people rely on wood, charcoal, dung, crop waste, or coal to meet basic energy needs. Cooking with solid fuels creates harmful smoke and particulates that fill homes and the surrounding environment. Household air pollution from cooking with solid fuels is responsible for 3.9 million deaths a year—about one every 8 seconds. In many places, including cities but also nearby rural areas, exposure to air pollution exposure is the main environmental threat to health. Long-term exposure to high levels of fine particulates in the air contributes to a range of health effects, including respiratory diseases, lung cancer, and heart disease, resulting in 3.2 million deaths annually. Not only does exposure to air pollution affect the health of the world’s people, it also carries huge economic costs and represents a drag on development, particularly for low and middle income countries and vulnerable segments of the population such as children and the elderly.
Limitations and Exceptions: Pollutant concentrations are sensitive to local conditions, and even monitoring sites in the same city may register different levels. Direct monitoring of PM2.5 is still rare in many parts of the world, and measurement protocols and standards are not the same for all countries. These data should be considered only a general indication of air quality, intended for cross-country comparisons of the relative risk of particulate matter pollution. The guideline set by the World Health Organization (WHO) for PM2.5 is that annual mean concentrations should not exceed 10 micrograms per cubic meter, representing the lower range over which adverse health effects have been observed. The WHO has also recommended guideline values for emissions of PM2.5 from burning fuels in households.
Statistical Concept and Methodology: Michael Brauer, Greg Freedman, Joseph Frostad, Aaron van Donkelaar, Randall V. Martin, Frank Dentener, Rita van Dingenen, Kara Estep, Heresh Amini, Joshua S. Apte, Kalpana Balakrishnan, Lars Barregard, David Broday, Valery Feigin, Santu Ghosh, Philip K. Hopke, Luke D. Knibbs, Yoshihiro Kokubo, Yang Liu, Stefan Ma, Lidia Morawska, José Luis Texcalac Sangrador, Gavin Shaddick, H. Ross Anderson, Theo Vos, Mohammad H. Forouzanfar, Richard T. Burnett, and Aaron Cohen. 2016. “Ambient Air Pollution Exposure Estimation for the Global Burden of Disease 2013.” Environmental Science & Technology 50, no. 1: 79–88. Data on exposure to ambient air pollution are derived from estimates of annual concentrations of very fine particulates produced by the Global Burden of Disease study, an international scientific effort led by the Institute for Health Metrics and Evaluation at the University of Washington. Estimates of annual concentrations are generated by combining data from atmospheric chemistry transport models, satellite observations of aerosols in the atmosphere, and ground-level monitoring of particulates. Overlaying PM2.5 estimates with gridded population data, the percent of a nation's people that lives in areas where PM2.5 concentrations exceed recommended levels is calculated by summing the population for grid cells where PM2.5 concentrations are beyond a threshold value, in this case 10 micrograms per cubic meter, and then dividing by total population.
Aggregation method: Weighted average