Hong Kong's Air Pollution: A Serious Health Crisis

Air pollution in Hong Kong is a pressing issue, with the territory facing two main challenges: local street-level pollution and regional smog. The former is primarily caused by diesel vehicles, while the latter is a result of a combination of pollutants from motor vehicles, marine vessels, industry, and power plants. The impact of air pollution on visibility and public health is significant, with the Hong Kong Medical Association estimating that air pollution exacerbates asthma, impairs lung function, and increases the risk of cardio-respiratory death. While the government has implemented various measures to tackle air pollution, such as the Clean Air Plan for Hong Kong 2035 and vehicle emission control programs, the territory continues to face challenges in improving air quality and protecting the health of its residents.

Hong Kong's air pollution is caused by motor vehicles, marine vessels, and power plants

Hong Kong's air pollution is a serious issue, with the territory ranking 63rd out of 138 regions in the world for poor air quality. The city's air pollution is primarily caused by motor vehicles, marine vessels, and power plants.

Motor vehicles are a significant contributor to Hong Kong's air pollution, particularly diesel vehicles such as trucks, buses, and light buses, which produce high levels of nitrogen oxides (NOx) and particulate matter. With approximately 275 vehicles per kilometre, Hong Kong has one of the highest vehicle densities in the world. The idling engines of cars, trucks, and buses contribute to local street-level pollution, which is one of the two greatest challenges faced by the city, along with regional smog.

Marine vessels, including cruise liners and container ships, are also major sources of air pollution in Hong Kong. These vessels emit pollutants such as sulphur dioxide, nitrogen oxides, and particulate matter. Cruise liners, which continue to run their engines while berthed to power onboard facilities, can emit as much sulphur dioxide as 25,000 diesel buses. Ocean-going vessels account for a large proportion of polluting emissions, with container ships alone responsible for 60% of these emissions.

Power plants are another significant contributor to Hong Kong's air pollution. The two major electricity companies, China Light and Power and HK Electric Holdings, emit over 75,000 tonnes of carbon dioxide into the air daily. Coal-fired power stations, in particular, have been identified as a major source of pollution, contributing to both local and regional air quality issues.

In addition to these primary sources, other factors also contribute to Hong Kong's air pollution. Construction and renovation activities, for example, generate significant amounts of dust and other pollutants, including volatile organic compounds (VOCs) and airborne microplastic dust. Waste incineration, sewage treatment, and fireworks are other sources of air pollution in the city.

The Hong Kong government has recognised the severity of the air pollution problem and has implemented various measures to address it. The Clean Air Plan for Hong Kong, first released in 2013 and updated in 2021, outlines strategies to tackle pollution from power plants, land and sea transport, and non-road mobile machinery. The government has also set Air Quality Objectives (AQOs) and introduced the Air Quality Health Index (AQHI) to inform the public about the health risks of air pollution and help them take precautionary measures.

The two greatest challenges are local street-level pollution and regional smog

Hong Kong's air pollution is mainly caused by motor vehicles, marine vessels, and power plants. The two most pressing issues are local street-level pollution and regional smog.

Local street-level pollution is primarily caused by diesel vehicles, particularly trucks, buses, and light buses. The government has implemented various measures to address this problem, including an incentive-based programme to phase out old diesel commercial vehicles, the replacement of catalytic converters and oxygen sensors in liquefied petroleum gas (LPG) taxis and light buses, and tighter vehicle emission standards. These measures have led to a significant reduction in key air pollutants at the roadside, with respirable suspended particulates (PM10) and nitrogen dioxide (NO2) concentrations decreasing by 38% and 41%, respectively, from 2012 to 2021.

Additionally, the government announced the Hong Kong Roadmap on the Popularisation of Electric Vehicles in March 2021, aiming to promote the adoption of electric vehicles and improve air quality further. As of 2020, roadside levels of nitrogen dioxide, respirable suspended particulates, fine suspended particulates, and sulphur dioxide have decreased by 40-50% compared to 2010.

Regional smog, on the other hand, is caused by a combination of pollutants from motor vehicles, industry, and power plants in Hong Kong and the neighbouring Pearl River Delta region. To tackle this issue, the government released the Clean Air Plan for Hong Kong in 2013, with a progress report published in 2017. The plan outlined measures to address air pollution from power plants, land and sea transport, and non-road mobile machinery, and to strengthen collaboration with Guangdong to address regional pollution. The government also set Air Quality Objectives (AQOs) in the Air Pollution Control Ordinance, which are reviewed at least once every five years to improve air quality and protect public health.

The impact of air pollution on health is significant. Studies have shown that roadside pollution levels contribute to 90,000 hospital admissions and 2,800 premature deaths annually in Hong Kong. The Hong Kong Medical Association warns that air pollution can aggravate asthma, impair lung function, and increase the risk of cardio-respiratory death. Therefore, the government's efforts to improve air quality are crucial in mitigating these health risks.

The Hong Kong government has implemented measures to control vehicle emissions

Hong Kong's air pollution is mainly caused by motor vehicles, marine vessels, and power plants. The two most pressing issues are local street-level pollution and regional smog. The Hong Kong government has implemented measures to control vehicle emissions and improve air quality.

In March 2013, the government released the first Clean Air Plan for Hong Kong, which outlined measures to address air pollution from power plants, land and sea transport, and non-road mobile machinery. The plan also aimed to strengthen collaboration with Guangdong to address regional pollution. A progress report published in June 2017 highlighted the implementation and achievements of the plan.

To reduce transportation emissions, the government has promoted the adoption of electric vehicles (EVs). In 2018, the government began offering incentives such as tax allowances for car owners who switch from fossil fuel vehicles to EVs. They have also installed EV charging stations in government car parks and public buildings and subsidised the installation of EV charging stations in existing private residential buildings. These efforts have shown results, as in 2022, the number of new EVs registered surpassed new fossil fuel cars for the first time.

The government has also tightened vehicle emission standards for newly registered motor vehicles. Since July 1, 2017, the emission standards for new vehicles have been raised from Euro V to Euro VI, resulting in a significant reduction in nitrogen oxide and respirable suspended particulate emissions. Similar standards have been implemented for diesel private cars, with the California LEV III standard adopted to regulate their emissions effectively.

Additionally, the Environmental Protection Department (EPD) has been crucial in tackling air pollution. They publish the Hong Kong Air Pollutant Emission Inventory annually and release hourly Air Quality Health Index (AQHI) reports to inform the public about short-term health risks associated with air pollution. The AQHI is reported on a scale of 1 to 10+ and is grouped into five health risk categories with corresponding health advice. The EPD is committed to continuously improving air quality and safeguarding public health.

The Clean Air Plan for Hong Kong 2035 aims to enhance air quality

Hong Kong's air pollution is mainly caused by motor vehicles, marine vessels, and power plants. The two biggest challenges are local street-level pollution and regional smog. Diesel vehicles, especially trucks, buses, and light buses, are the primary source of street-level pollution. Smog is caused by a combination of pollutants from motor vehicles, industry, and power plants in Hong Kong and the Pearl River Delta.

The Clean Air Plan for Hong Kong 2035 was announced in June 2021. It aims to build on past successes and make Hong Kong a more liveable city with air quality comparable to major international cities by 2035. The plan focuses on six key areas: green transport, comprehensive emissions reduction, clean energy, scientific management, and regional collaboration.

Green transport initiatives include the promotion of electric vehicles and associated supporting infrastructure. The government has also implemented a comprehensive vehicle emission control programme, resulting in significant reductions in roadside levels of nitrogen dioxide, respirable suspended particulates, fine suspended particulates, and sulphur dioxide since 2010.

The comprehensive emissions reduction strategy involves continuing to implement measures to reduce emissions from vehicles and vessels and tightening control over the content limits of volatile organic compounds. The clean energy strategy focuses on further reducing emissions from electricity generation and exploring new low-carbon energy sources such as hydrogen energy and liquefied natural gas.

The scientific management strategy involves adopting innovative technology to monitor air quality and releasing more detailed air quality information to the public. Regional collaboration aims to formulate joint regional air pollutant emission reduction targets and strengthen air pollution research and monitoring in the Guangdong-Hong Kong-Macao Greater Bay Area.

Air pollution in Hong Kong has serious health implications for residents

The health risks posed by air pollution are significant, particularly for vulnerable groups such as children, the elderly, and individuals with heart or respiratory conditions. Studies have linked air pollution to a range of adverse health outcomes, including exacerbating asthma, impairing lung function, and increasing the risk of cardio-respiratory death. The Hong Kong Medical Association estimates that for every increase of 10 micrograms per cubic metre of pollutants, the risk of cardio-respiratory death rises by 2 to 3 per cent. Alarmingly, roadside pollution levels in Hong Kong are associated with 90,000 hospital admissions and 2,800 premature deaths annually.

The territory has witnessed a decline in regional air quality, leading to a dramatic decrease in visibility. In 2004, low visibility occurred 18% of the time, the highest ever recorded, according to the Hong Kong Observatory. This trend has continued, with the Environmental Protection Department reporting "very high" health risk levels in multiple districts in April 2025 due to a dry and hazy period influenced by a dusty airstream from the north.

To address these pressing issues, the Hong Kong government has implemented various measures and plans to improve air quality and safeguard public health. The Clean Air Plan for Hong Kong, first introduced in 2013 and updated in 2021, outlines strategies to tackle pollution from power plants, land and sea transport, and non-road mobile machinery. The government is also promoting the adoption of electric vehicles and has implemented vehicle emission control programmes, resulting in significant improvements in air quality. Additionally, Hong Kong is collaborating with neighbouring regions, such as Guangdong, to implement joint plans to address regional smog and bring pollution levels under control.

Despite these efforts, air pollution remains a serious concern in Hong Kong, and the government continues to review and strengthen its Air Quality Objectives to protect the health and well-being of its residents.

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