Global review of national ambient air quality standards for PM10 and SO2 (24 h)
Literature comparing national ambient air
quality standards (AAQSs) globally is scattered and sparse.
Twenty-four hour AAQSs for particulate matter <10 μm in aerodynamic diameter (PM10) and sulfur dioxide (SO2) in 96 countries were identified through literature review, an international survey, and querying an international legal database. Eighty three percent, of the 96 countries with information on the presence or absence of AAQSs, have 24- h AAQSs for either PM10 or SO2. Slightly more countries have 24-h AAQSs for SO2 (76 countries) than PM10 (69 countries). The average 24-h AAQSs for PM10 and SO2 are 95 μg/m3 (95% confidence interval [CI], 82–108 μg/m3, n= 68) and 182 μg/m3 (95% CI, 158–205 μg/m3, n=73). The population-weighted average AAQS for PM10 is 98 and 155 μg/m3 for SO2. The average AAQS for both PM10 and SO2 are substantially higher than the recommended World Health Organization Air Quality Guideline (WHO AQG) value. Several countries have promulgated AAQSs at the WHO AQG value for PM10, but none for SO2. Further examination in selected countries found that air quality monitoring data, existing AAQSs in other countries, environmental epidemiology studies, and the WHO AQGs are considered the most often in establishing or revising AAQSs.