South China Morning Post
People on Hong Kong buses are breathing air containing twice the level of fine pollutants as that deemed safe by the World Health Organisation.
Friends of the Earth conducted tests in June and July, and found the average level of PM2.5 particles – those 2.5 microns or less in diameter – in buses on 13 routes was 53.11 micrograms per cubic metre. The WHO calls for a limit of 25.
Such particles are roughly 1/28th the thickness of a human hair and because they are so fine, can lodge deep in the lungs. Some respirable suspended particles can cause cancer.
The PM2.5 levels in buses were about the same as on the roadside because the vehicles’ ventilation systems do not filter out fine particles.
The study was limited to franchised buses, and so excluded minibuses.
The highest level recorded was in a bus on Yee Wo Street in Causeway Bay – 171 microns per cubic metre – on Citybus route 5.
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