Guest Comments by the Civic Exchange Public-Policy Think-Tank

HONG KONG -- Recently, we revealed the findings of a roadside-air-pollution study covering all 18 districts in Hong Kong. The study exposes key factors that determine roadside-pollution levels and identifies that shipping emissions from the port can be a big source of pollutants.

The survey, conducted by Professor Chak Chan and a team from the Hong Kong University of Science and Technology, used the real-time Mobile Air-Monitoring Platform (MAP), a specially designed van with equipment to measure air-quality while traveling. It showed high roadside-pollution levels across Hong Kong.

Civic Exchange CEO Christine Loh called the MAP output a valuable new tool to interpret, communicate and counter the threat of roadside air pollution. Some control measures proposed by the government could be assessed against the new data.

“Professor Chan's research lays out the anatomy of roadside pollution. Knowing the contributing factors, we can use this detailed information to identify and fix specific problems. We see immediate applications for placing low-emissions zones, creating more urban open spaces and reducing ship emissions.”

The study covered many streets, roads and highways, finding big variations in air quality. These depend on certain factors:

Traffic Volume
The more vehicles, the more pollution emitted. The Kwun Tong Bypass is a typical busy highway with high pollution.

Congestion
The more traffic stops, starts and moves slowly (due to traffic lights, tight corners, merging lanes or other blockages), the more pollution. Nathan Road in Mong Kok is consistently congested.

Ventilation
The more enclosed a road is (by “street canyons” between skyscrapers and flyovers, for example Hennessy Road), the greater the concentration of pollution. If roads pass open spaces (like the Kwun Tong Bypass does), pollutants disperse more and concentrations stay lower. When pollution levels differ dramatically, even between places just a few metres apart, such variations often arise from air ventilation.

Shipping
Sulphur-dioxide emissions from container ships at the Kwai Chung Container Port have a measurable influence on nearby roadside pollution.

Plotting school sites against the roadside-pollution data shows how vulnerable children are, regardless of socio-economic status. The same goes for hospital patients, including the elderly.

The public, legislators and officials should better appreciate the scale of the danger to public health. Hong Kong needs a new urgency to reduce roadside emissions.

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