The air quality in Hong Kong, especially roadside pollution, remains an untamed challenge for public health in the half year of 2018. Such condition reflects the unsatisfactory performance of Carrie Lam’s administration, which is marking the first anniversary of her office, in air pollution control policies ranging from end-of-pipe control to alleviating traffic congestion, as committed in Clean Air Plan for Hong Kong 2013.

Meanwhile, 2018 is also a year to review the air quality objectives (AQOs) as stipulated by Air Pollution Control Ordinance. With protecting public health as the overarching principle, Clean Air Network calls for the government to tighten HKAQOs to meet World Health Organisation (WHO)’s Air Quality Guidelines (AQGs), and devise Clean Air Plan 2.0 to deliver a more progressive framework of air pollution control.

Clean Air Network analyses the air quality data and summarises the trend for the first half of 2018:

Air Pollution continues to be concentrated in the west of Hong Kong;

  1. First Critical challenge – Roadside pollution remains at stake and breaching WHO recommended level;
  2. Second Critical challenge – Public Health remains at stake as roadside air pollution continues to breach WHO recommended safe level

In response to the Clean Air Plan for Hong Kong 2013 – 2017 Progress Report (hereafter referred as the report) published by Environment Bureau in 2017, Clean Air Network compares the air quality data in the first half of 2018 and finds the concentrations of the two roadside pollutants, namely Nitrogen Dioxide (NO2) and PM10, exceeding the projected levels in the last two years. Even though the targets stated in the report are met in 2020, the projected NOand PM10 levels will remain surpassing the WHO standards by 77% and 59%, posing a significant threat to public health.

 1.Air Pollution remains concentrated in the west of Hong Kong

 The main air pollutants, including NO2, Sulphur Dioxide (SO2), PM2.5 and PM10, are mainly concentrated in the west of Hong Kong. The only exception is Ozone (O3), which is an indicator of regional pollution.

2018年上半年空氣質素回顧 暨 新政府空氣政策檢討 傳媒發佈會 pic1

Table 1 – The comparison of concentrations of air pollutants between the east and the west of Hong Kong in the first half of 2018
2. Public Health remains at stake as roadside air pollution continues to breach WHO recommended safe level

Such east-west difference is prevalent in term of roadside pollution. NO2, the main pollutant generated from transport, ranks the highest from Kwai Chung, Sham Shui Po to Tsuen Wan. These districts are all clustered in the west of Hong Kong. These are also areas with high population density and social deprivation rate.

Roadside pollution remains an acute problem in Hong Kong. Clean Air Network compares the roadside pollutants (including NO2, PM2.5 and PM10) over the first six months of 2016 – 2018, and finds that those pollutants remain one to three times higher than WHO recommended levels.

2018年上半年空氣質素回顧 暨 新政府空氣政策檢討 傳媒發佈會 oi

Table 2 – NO2 concentration in the first 6 months for 2016 – 2018
3. Ozone marks the highest in 20 years, posing another critical challenge

 From the first half of 2018 data, O3 is on the rise and marks the highest point over the course of past 20 years. Clean Air Network observes the high pollution episodes in the first half of 2018, and finds that both O3 and NO2 rose in parallel during the episodes. It shows that the two pollutants are the critical challenges with respect to air pollution control in Hong Kong.2018年上半年空氣質素回顧 暨 新政府空氣政策檢討 傳媒發佈會 3333

Table 3 – The trend of Ofrom 1996 to 2018

Hong Kongers are paying a heavy price for the unhealthy air. According to Hedley Environmental Index by HKU School of Public Health, 867 premature deaths were resulted in the first half of 2018, equivalent to the eightfold of traffic fatalities in 2017. The direct economic loss amounted to HKD 10.4 billion, equivalent to the cost of providing 14,900 public housing units.

Air Pollution also contributes to a great deal of medical burden. The medical visits due to air pollution in the first half of 2018 totaled 1.26 million. The hospital days totaled 59,569, equivalent to the one-month full capacity of Prince of Wales Hospital.

The current policies are not adequate to address the public health threat

Given that the 2020 targets remain surpassing WHO standards by 77% and 59%, public health is still insufficiently protected. Therefore, the government should address the following inadequacies:


 There are limitations to end-of-pipe control. In order to effectively lower roadside pollution, the key is to alleviating traffic congestion. In the past 10 years (2007 – 2016), the 33% rise in number of vehicles outgrew the rise in population. The total vehicle kilometers travelled rocketed to 13.692 billion kilometers in 2016.

 b)The weaknesses of current AQOs

–          The AQOs are not yet tightened to WHO AQG;

–          The government is not accountable for non-compliance with the AQOs;

–          The overarching principle of reviewing AQOs is not based on public health

Given the inadequacies in regulatory framework and policy intervention, measures that can most effectively protect public health are confronted with drawbacks in face of practicability consideration.

Clean Air Plan 2.0 is Needed

Hong Kong Clean Air Plan was published in 2013, with projection until 2020.

To continue to improve air quality until it meets a safe standard, the government must deliver a new action plan projecting 2020 onwards, detailing strategies to improve both ambient and roadside pollution. Such measures should cover strengthened emission control, including the timeline towards complete zero-emission public transport. In terms of transport management, indicators should be set on the growth of number of vehicles and total vehicle kilometres travelled.

Clean Air Network estimates that if exclusive use of franchised buses is regulated in the existing low emission zones, 646 tonnes of Nitrogen Oxides (NOx) can be prevented from injecting onto the roadside every year, equivalent to the annual emission of all private cars in Hong Kong.

More importantly, Hong Kong AQOs should be immediately tightened to WHO AQGs. According to the study ‘Developing an Instrument for Assessing the Health and Economic Impacts of Air Pollution in Hong Kong ‘ conducted by Professor Tsz-wai Wong (CUHK JC School of Public Health and Primary Care), if the air quality (based on 2014 figure) can be tightened to WHO AQGS, 6,308 lives[1] can be saved every year onwards. Therefore, the 2018 review is a pivotal time to tighten HK AQOs to WHO AQGs with the priority for safeguarding public health.

‘Last but not least, public health should be the key consideration of setting air quality objectives. Such important criterion should not give way to practicability,’ commented Loong Tsz-wai, Senior Community Relations Manager of Clean Air Network.

Appendix: Policy Review of Air Pollution Control in First Half of 2018

Story posted on
18th Jul, 2018


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