Summary of World Health Organization (WHO) Air Quality Guideline (AQG):
PM10 24-hr mean of 50 μgm-3 & annual mean of 20 μgm-3,
NO2 1-hr mean of 200 μgm-3 & annual mean of 40 μgm-3,
SO2 24-hr mean of 20 μgm-3 & annualized mean of 5 μgm-3,
O3 maximum 8-hr mean of 100 μgm-3 & annualized mean of 23.5 μgm-3
PM10 24-hr mean of 50 μgm-3 & annual mean of 20 μgm-3,
NO2 1-hr mean of 200 μgm-3 & annual mean of 40 μgm-3,
SO2 24-hr mean of 20 μgm-3 & annualized mean of 5 μgm-3,
O3 maximum 8-hr mean of 100 μgm-3 & annualized mean of 23.5 μgm-3
WHO guidelines do not indicate totally safe air quality, only safer air. Hong Kong's pollutant levels violate the safer WHO limits on most days of the year. This analysis indicates the frequency and magnitude of the problem.
In Year 2010, monthly pollutant concentrations at all urban monitoring stations violated the expected WHO annual limits during cool season (January to March and October to December). This indicates there was no effective protection to public health (Figure). Among all 14 monitoring stations, only the Eastern station in July showed that air quality complied with the annual AQG of PM10 and NO2 and with the expected annual limit for SO2 and O3. All other stations, in all months of the year, showed violations of either single or multiple guidelines for the four criteria pollutants.
In Year 2010, monthly pollutant concentrations at all urban monitoring stations violated the expected WHO annual limits during cool season (January to March and October to December). This indicates there was no effective protection to public health (Figure). Among all 14 monitoring stations, only the Eastern station in July showed that air quality complied with the annual AQG of PM10 and NO2 and with the expected annual limit for SO2 and O3. All other stations, in all months of the year, showed violations of either single or multiple guidelines for the four criteria pollutants.
Daily or hourly pollutant concentrations at urban monitoring stations also frequently violated the WHO short-term AQG, mostly during the cool season for PM10, NO2 and O3 and warm season for SO2 (Figure). Among all 14 stations, Eastern station has the least number of days exceeding any of the WHO short-term AQG of the four criteria pollutants (128 days), followed by Tai Po (132 days), Kwun Tong (137 days), Yuen Long (152 days), Tung Chung (152 days), Central/Western (157 days), Sha Tin (167 days), Sham Shui Po (169 days), Tsuen Wan (183 days), Mongkok (184 days), Tap Mun (191 days), Central (207 days), Kwai Chung (231 days) and Causeway Bay (256 days).
These large numbers of days on which the air was unsafe to breathe, because of violation of the minimum standard for health protection, show that everyone in Hong Kong has a very high exposure to toxic chemicals which cause diseases of the lungs, heart, and blood vessels. They also cause health problems in diabetics, in pregnant mothers, the sick, elderly and poor.
Edited by AJH
These large numbers of days on which the air was unsafe to breathe, because of violation of the minimum standard for health protection, show that everyone in Hong Kong has a very high exposure to toxic chemicals which cause diseases of the lungs, heart, and blood vessels. They also cause health problems in diabetics, in pregnant mothers, the sick, elderly and poor.
Edited by AJH
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