Nature | Hong Kong’s historic trams are choking from roadside pollution

A tram stops as pedestrians cross the main street in Central, Hong Kong

Hong Kong’s historic double-decker trams are not just one of the city’s most popular tourist attractions, they are also one of its most hazardous.
Air quality often exceeded safe levels along the entire length of the tram line, and not just in Central and Causeway Bay districts as previously believed, according to research by the Hong Kong University of Science and Technology.
“Clearly from this study it’s not limited to those areas,” Alexis Lau, a professor from the university who specializes in air quality research, said at a press conference Thursday. “This helps us map the distribution of pollution much better.”
The data, gathered by mobile monitoring devices placed inside the trams between March 2014 and February 2015, showed that even the least polluted sections of the route exceeded World Health Organization guidelines for roadside air quality on at least 80 days. In Central and Causeway Bay: More than 280 days.
“That means that more than half the year, the air is not safe to breathe,” said Jimmy Fung, a HKUST professor who participated in the study.
While the trams are considered the least polluting mode of transport, they put riders most at risk because their open windows and doors leave people completely exposed to roadside pollution.
“Who is the culprit? Tramways are the victim, they are run on electricity and very clean,” said Simon Ng, chief research officer of think tank Civic Exchange, which collaborated on the study with the assistance of Hong Kong Tramways Ltd.
Ng urged policy makers to consider ways to reduce emissions by reducing or removing road traffic and creating pedestrian- only areas as well as explore ways to improve wind ventilation and air dispersion. Frederik Balfour, Bloomberg