In Figure 2 we compare the full distributions of average
PM2.5 concentrations across major cities in India, China,
Europe and the United States (US), using the WHO Ambient Air
Pollution Database. Indian cities, with an average PM2.5 concentration
of 46.0 µg/m3, are far more polluted than those in
Europe (21.7 µg/m3
) or the US (9.6 µg/m3
), and polluted even
in comparison to China, where cities average 40.4 µg/m3. A
number of Indian cities have very high fi ne particulate levels,
above 75 µg/m3. We also compare the ambient air quality
standards for annual average PM2.5 concentrations. There is
substantial variation in the levels of stringency adopted by
countries while setting national air quality standards. At the
current prescription of 40 µg/m3
for annual PM2.5, the Indian
NAAQS is four times the WHO guideline and is the least stringent
of the four regions.
In Figure 2 we compare the full distributions of averagePM2.5 concentrations across major cities in India, China,Europe and the United States (US), using the WHO Ambient AirPollution Database. Indian cities, with an average PM2.5 concentrationof 46.0 µg/m3, are far more polluted than those inEurope (21.7 µg/m3) or the US (9.6 µg/m3), and polluted evenin comparison to China, where cities average 40.4 µg/m3. Anumber of Indian cities have very high fi ne particulate levels,above 75 µg/m3. We also compare the ambient air qualitystandards for annual average PM2.5 concentrations. There issubstantial variation in the levels of stringency adopted bycountries while setting national air quality standards. At thecurrent prescription of 40 µg/m3 for annual PM2.5, the IndianNAAQS is four times the WHO guideline and is the least stringentof the four regions.
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