Press release:

The Clean Air Network (CAN), an air pollution concerning NGO based in Hong Kong, today released its annual air quality review and found that there is a strong correlation between traffic congestion and air pollution. The group called for the city’s attention on the continuous growth of vehicle number which offset effort made to improve roadside air quality and public health.

The analysis is based on 2016 air pollution data collected from the Environmental Protection Department’s 16 monitoring stations in Hong Kong, and traffic data collected by Transport Department.

CAN found that the level of Nitrogen Dioxide at roadside monitoring stations, has never reached Hong Kong’s Air Quality Objectives (note: for NO2, Hong Kong’s standard is the same as World Health Organization’s Air Quality Guideline).

CAN then mapped the diurnal variation of NO2 level at different districts, and suggested that the roadside air pollution has been contributed by road transport. The health risk escalated by as much as 2.6 times when it is at traffic peak hour, compared to quiet hours.

Nitrogen Dioxide, one of the key pollutants emitted mainly by road transport, was found to be at higher level at the Western part of Hong Kong, including New Territories West (Tuen Mun, Tsuen Wan, Kwai Chung), Kowloon West (Sham Shui Po). These districts not only had a higher traffic flow than the eastern part of Hong Kong, they were also higher level of air pollution observed.

CAN argues that, too many vehicles on the road causes traffic congestion and high level (concentration) air pollution. Spending long journey time on the road, the commuters are at the same time exposed to high level (concentration) of air pollution.

According to figures from Transport Department, the number of vehicles has almost doubled over the last 20 years. Since year 2000, the EPD has invested resources as much as HK$14.3 Billion on improving air quality. Except for improvement made on Particulate Matters, the roadside level of Nitrogen Dioxide has remained unsafe over the last 20 years and stayed as high as two times the WHO’s standard.

“The growth of vehicles number has gone uncontrollable and offset some of the effort made by the government, especially to reduce NO2 (82ug/m3 for roadside stations in 2016, more than double of WHO standard).” The CEO of Clean Air Network, Patrick Fung, said.  “The next term of government should look at this imminent issue as top of the agenda. Traffic has been a daily headache to all Hong Kong people, and is impediment to the improvement of air quality, public health and other living qualities.”

Long term exposure to high concentration of air pollution will lead to cardiovascular and respiratory disease. Studies have shown associations of nitrogen dioxide (NO2) in outdoor air with adverse effects on health, including reduced life expectancy. According to the Hedley Environmental Index of HKU School of Public Health, the air pollution in 2016 has caused 1686 premature deaths, 21.6 billion direct economic loss and 2.65 million additional doctor visits.

Key figures

Pollutants Monitoring stations with 75% of the time not safe  (exceed WHO standard)
PM 2.5 All monitoring stations except Tung Chung, Sha Tin, Eastern
PM 10 Causeway Bay, Tuen Mun, Mongkok, Kwai Chung, Kwun Tong
NO2 Causeway Bay, Mongkok, Central


Almost double of car registration in 20 years
press release pic 2

Hong Kong’s roadside NO2 level has remained at unsafe level, doubling that of WHO standard for the last 20 years
press release pic 5

Correlation between Nitrogen Dioxide and traffic flow at trunk roads
press release pic 6


Story posted on
12th Jan, 2017


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