Increasing air pollution from the roads

Traffic pollution creates one of the biggest hazards to health in Hong Kong. Roadside pollutant levels affect at least 60% of the population. The evidence is clearly provided by the EPD monitors but there is no commensurate action by government to protect health.

The trend of nitrogen dioxide (NO₂) levels at roadside stations, as shown by the levels at Central station (Figure), is currently rising higher every year. In December 2010, the monthly average concentration in Central (162μgm^-3) reached the highest monthly record since the station has been in operation. This level exceeded by 300% the World Health Organization Air Quality Guideline annual limit for NO₂ of 40μgm^-3 and represents the near-ground air quality, which contributes to more than 60% of the exposure of the Hong Kong population to air pollutants (Lai et al 2010).

This increasing trend of urban roadside NO₂ was clearly due to emissions from local urban traffic and not due to the emissions dispersed from across the border. There was no upward trend in the background or regional ambient NO₂ levels during the same period (Figure). NO₂ concentrations at Tap Mun (Grass Island) are consistently low in that traffic free environment.

Traffic pollution is major threat to public health and both particulate and nitrogen dioxide levels, especially in the cool season, indicate that abatement measures are failing to produce improvements on an acceptable timescale.

Edited by AJH

Reference:

Lai HK, Wong CM, McGhee SM, Hedley AJ. Assessment of the health impacts and economic burden arising from proposed new air quality objectives in a high pollution environment. Open Epidemiology. 2011;4:106-122. http://www.benthamscience.com/open//toepij/articles/V004/SI0001TOEPIJ/106TOEPIJ.pdf