Cleaning the Air at Street Level

Street Level Air Pollution

Progress of Vehicle Emissions Control Measures

Tightening Fuel and Vehicle Emission Standards

Strengthening Emission Inspection and Enforcement

Promoting Better Vehicle Maintenance

Promoting Electric Vehicle Adoption

Vehicle Emission Inventory for Local Vehicles

Roadside Air Quality Trends

 

 

 

Street level Air Pollution

In our busy streets, air pollution is mainly caused by motor vehicles, particularly diesel vehicles such as trucks, buses and light buses which emit a large amount of particulates and nitrogen oxides (NOx). The pollutants are often trapped at roads flanked by very tall buildings, making it difficult to clean up roadside air pollution.

Photo of busy street

 

Progress of Vehicle Emissions Control Measures

The Government has adopted an integrated vehicle emission control strategy, which has the following 6 major elements, to tackle roadside air pollution issues:

  • Adopt tighter fuel and vehicle emission standards;
  • Adopt cleaner alternatives to diesel vehicles where practicable;
  • Control emissions from the remaining diesels with devices that reduce pollutants;
  • Strengthen vehicle emission inspections and enforcement against grossly emitting vehicles;
  • Promote better vehicle maintenance; and
  • Promote electric vehicle (EV) adoption.

 

Latest Initiatives

  • Tightened the emission standards for first registered motorcycles to Euro 4 from October 2020, and for first registered light buses (with a design weight of more than 3.5 tonnes) and buses (with a design weight of not more than 9 tonnes) to Euro VI from 1 March 2021;
  • Expanded the scope of the New Energy Transport Fund (previously named Pilot Green Transport Fund) to subsidise the testing and encourage more widely the use of green innovative transport technologies for a variety of commercial transport tools;
  • Launched a $3.5 billion EV-charging at Home Subsidy Scheme (EHSS) in two phases starting from October 2020 to subsidise the installation of EV charging-enabling infrastructure in car parks of existing private residential buildings and further facilitate EV owners to install EV chargers of their choice and charge their EVs at home in the future in a simple and easy manner;
  • Take forward measures set forth in the Hong Kong Roadmap on Popularisation of Electric Vehicles announced in March 2021 and move towards the target of zero vehicular emissions early;
  • Launched the Pilot Scheme for Electric Public Light Buses in March 2024 to test the operational performance of the existing electric public light bus (e-PLB) models available in the market, so as to evaluate the feasibility of the application of e-PLBs and the associated charging arrangement in Hong Kong; 
  • Announced the Green Transformation Roadmap of Public Buses and Taxis in December 2024. Major measures include subsidising franchised bus operators to purchase electric franchised buses and the taxi trades to purchase electric taxis under Applications for Use of the New Energy Transport (NET) Fund; and
  • Launched the Funding Scheme to Trial of Hydrogen Fuel Cell Heavy Vehicles under Applications for Trial of NET Fund in December 2024.
     

 

Previous Initiatives

Year

 Key Policy and Control Measures on Vehicular Emissions

2020-2024
  • Injected $800 million to NET Fund in 2020 to expand the subsidy scope under Application for Trial; and introduce Application for Use to subsidise the transport trade for procurement of new energy transport tools suitable for local use; and
  • Launched an incentive cum regulatory scheme in 2020 to progressively phase out some 40,000 Euro IV Diesel Commercial Vehicles (DCVs) by end 2027 (detailed in Phasing Out Euro IV Diesel Commercial Vehicles – Ex-gratia Payment Scheme).

2017-2019

  • Tightened the emission requirements of the Franchised Bus Low Emission Zones (FBLEZs) at Central, Causeway Bay and Mong Kok to Euro V emission standards or above from 31 December 2019; and
  • Tightened the vehicle emission standards for first registered motor vehicles (except for diesel private cars, buses with a design weight of not more than 9 tonnes, light buses with a design weight of more than 3.5 tonnes, motorcycles and tricycles) to Euro VI in phases from July 2017. For first registered diesel private cars, the standards were tightened to California LEV III from October 2017.

2014-2017

  • Set up FBLEZs at 3 busy road sections in Central, Causeway Bay and Mong Kok, allowing only buses meeting Euro IV or higher emission standards to run through from 31 December 2015;
  • Fully subsidised the franchised bus companies (FBC) to purchase 6 double-deck hybrid buses and 36 single-deck electric buses for trial in 2014 and 2015 respectively;
  • Deployed roadside remote sensing equipment to identify vehicles with excessive emission which strengthened the vehicle emission regime for petrol and LPG vehicle from September 2014 (detailed in in Strengthened Emissions Control for Petrol and LPG Vehicles);
  • Launched an incentive-cum-regulatory scheme in March 2014 to phase out pre-Euro IV DCVs. Service life of DCVs first registered on or after 1 February 2014 is also limited to 15 years (detailed in Phasing out Pre-Euro IV Diesel Commercial Vehicles); and
  • Funded the FBCs to retrofit 1 030 Euro II and III franchised buses with SCR devices and diesel particulate filters (DPF) from 2014 to 2017.

2011-2013

  • Subsidised vehicle owners to replace the catalytic converters and oxygen sensors of LPG / petrol taxis and light buses from August 2013 to March 2014;
  • Completed the incentive scheme for replacing Euro II DCVs in June 2013, involving 7 400 DCVs ;
  • Tightened vehicle emission standards for first registered motor vehicles (except for motorcycles and tricycles) to Euro V in phases starting from June 2012;
  • Set up the Pilot Green Transport Fund in 2011 ( renamed as the NET Fund in 2020) to subsidise and encourage the testing and wider use of green innovative transport technologies for a variety of commercial transport tools; and
  • Enacted the Motor Vehicle Idling (Fixed Penalty) Ordinance in 2011 (detailed in The Statutory Ban against Idling of Motor Vehicle Engines)

2007-2010

  • Tightened the specifications of motor vehicle diesel and unleaded petrol to Euro V standards from July 2010;
  • Completed the incentive scheme for replacing pre-Euro and Euro I DCVs in March 2010, involving about 17 000 DCVs;
  • Completed retrofitting Euro II and III buses with DPFs by FBCs in 2010; and
  • Launched the Tax Incentives for Environment-friendly Commercial Vehicles and the Tax Incentives for Environment-friendly Petrol Private Cars in April 2008 and April 2007 respectively to offer First Registration Tax (FRT) reduction to buyers of first registered environment-friendly commercial vehicle (on-going) and environment-friendly petrol private cars (ended on 31 March 2015).

2000-2007

  • Completed in 2004 a programme which retrofitted over 96% (or 34 000) pre-Euro heavy diesel vehicles that were not long idling vehicles, with catalytic converters, and completed in 2005 a programme for about 95% (or 2 500) long idling pre-Euro heavy diesel vehicles to do the same;
  • Implemented a regulation in April 2006 requiring pre-Euro heavy diesel vehicles, excluding long idling vehicles, to be equipped with suitable particulate reduction devices; and extended the same requirement in April 2007 to long idling pre-Euro heavy diesel vehicles;
  • Implemented a programme from August 2002 to the end of 2005 to incentivize replacing 6 000 diesel light buses with liquefied petroleum gas (LPG) or electric ones, offering $60,000 or $80,000 for replacing each diesel public light bus with LPG or electric one respectively, and exempting first registration tax for replacing diesel private light buses with LPG ones;
  • Completed a programme in 2001 which retrofitted over 80% (or 24 000) pre-Euro light diesel vehicles with particulate traps or catalytic converters;
  • Implemented a regulation in December 2003 requiring pre-Euro diesel light vehicles up to 4 tonnes to be installed with suitable particulate reduction devices; and
  • Implemented a programme from August 2000 to the end of 2003 offering $40,000 for replacing each of the 18 000 diesel taxis with LPG ones.

 

 

Tightening Fuel and Vehicle Emission Standards

Vehicle emission standards
 

Emission standards for first-registered vehicles have been tightened continuously since 1995. Currently the vehicle emission standards for motor vehicle first registration (except for diesel private cars, motor cycles and motor tricycles) were tightened to Euro VI (see table below). Compared with their Euro V counterparts, Euro VI heavy duty diesel vehicles emit about 80 per cent less nitrogen oxides (NOx) and 50 per cent less respirable suspended particulates (RSP or PM10), while Euro 6 light duty diesel vehicles emit about 55 per cent less NOx.

Prevailing vehicle emission standards (by category) and their implementation dates

Vehicle Category

Emission Standard

Implementation Date for First Registered Vehicle

Motor Cycle

Euro 4

1 October 2020

Motor Tricycle

Euro 3

1 January 2007

Private Car (diesel)

California LEV III

1 October 2017

Bus (design weight of more than 9 tonnes) and Goods Vehicle (design weight of more than 3.5 tonnes)

Euro VI On Board Diagnostics (OBD) Phase C

1 April 2019

Bus (design weight of not more than 9 tonnes) and Light Bus (design weight of more than 3.5 tonnes)

1 March 2021

Private Car (petrol) and Taxi

Euro 6c OBD Euro 6-2

1 September 2019

Goods Vehicle and Light Bus (both design weight of not more than 3.5 tonnes)

1 September 2020

Japan Motor Vehicle Emission Standards (except those vehicles with design weight of more than 3.5 tonnes), United States of America Motor Vehicle Emission Standards (except Motor Cycles and Motor Tricycles) are accepted by the Air Pollution Control (Vehicle Design Standards) (Emission) Regulations. For details, please refer to Schedule 17 to 20 of the Regulations.

If the Authority is of the opinion that the emission from a particular motor vehicle to which those regulations apply conforms to standards as stringent as, or more stringent than, the standards referred to in those regulations and applicable to it (e.g. the latest China Motor Vehicle Emission Standards), then for the purposes of those regulations, such vehicle shall be taken as conforming to the standards so referred to and so applicable.
 

Vehicle fuel standards

Petrol- We have tightened the sulphur content in unleaded petrol from 0.015% to 0.005% since January 2005 in tandem with the European Union.

 

Ultra low sulphur diesel (ULSD)- ULSD has a sulphur content of 0.005%, which is the Euro IV requirement for motor vehicle diesel. It became the only motor diesel fuel available at petrol filling stations in Hong Kong, after the Government introduced a concessionary duty on ULSD in July 2000. Since April 2002, ULSD has been the statutory minimum requirement for motor vehicle diesel, 3 years ahead of the European Union. Hong Kong is also the first place in Asia to introduce ULSD on a full scale for its vehicle fleet.

 

Euro V diesel- On 1 December 2007, the Government offered a concessionary duty rate of $0.56 per litre for Euro V diesel, which has a sulphur content of 0.001%. Since then, all petrol filling stations in Hong Kong are exclusively offering this fuel. Starting from 14 July 2008, the duty rate for Euro V diesel has been waived.

 

Biodiesel- The Air Pollution Control (Motor Vehicle Fuel) (Amendment) Regulation 2009 came into force on 1 July 2010. The Amendment Regulation provides statutory control on the specifications of motor vehicle biodiesel and the labelling requirement on selling of motor vehicle biodiesel with biodiesel content over 5%.

 

Euro V Motor Vehicle Fuels- As from 1 July 2010, we have tightened the statutory motor vehicle diesel and unleaded petrol specifications to Euro V level. The major difference between Euro IV and Euro V motor vehicle fuels (both diesel and petrol) is the tightening of the cap on sulphur content from 0.005% to 0.001%.

 

Strengthening Emission Inspection and Enforcement

Controlling smoky vehicles

 Photo of dynamometer smoke test

The Smoky Vehicle Control Programme (SVCP) has been in operation since 1988. This programme mainly targets diesel vehicles that emit excessive smoke due to poor maintenance. Smoky vehicle spotters who are trained and accredited by the Environmental Protection Department (EPD) will report diesel vehicles that emit excessive smoke on the road to EPD. EPD will issue Emission Testing Notices (ETNs) to the owners of the spotted vehicles, requiring them to fix the smoke problem and pass a chassis dynamometer smoke test within 12 working days. Vehicles failing the smoke test would have their licences cancelled by the Transport Department.

 Photo of joint operation with the Police

 

Hong Kong Police Force (HKPF) in collaboration with EPD have, from time to time, supported the programme by mounting roadside smoke-testing operations. Police officers will stop vehicles having excessive smoke emissions on road for a smoke test using a portable smokemeter. Fixed penalty ticket will be issued to the owners of vehicles failing the smoke test. The fixed penalty for smoky vehicle was raised from $450 to $1,000 on 1 December 2000. EPD will separately issue an ETN to the owner requiring them to fix the smoke problem and pass the smoke test at a DVETC within 12 working days.

A majority of vehicles emitting excessive smoke are aged and poorly maintained DCVs. To improve roadside air quality and better protect public health, EPD launched an incentive-cum-regulatory scheme in March 2014 to phase out progressively some 82 000 pre-Euro IV DCVs. The number of smoky vehicles on the road has been reduced in turn, resulting in a significant drop in the number of smoky vehicle reports made by the accredited spotters.

 

Strengthened control of emissions from LPG and petrol vehicles

From 1 September 2014 onwards, a strengthened vehicle emission regime for petrol and LPG vehicles has been implemented that includes limits for carbon monoxide (CO), hydrocarbons (HC) and NOx to improve roadside air quality. Roadside remote sensing equipment are deployed to identify vehicles with excessive emission which will be required to pass a chassis dynamometer emission test after repair. Failure to comply with the requirement will lead to cancellation of the licence of the vehicle by the Commissioner for Transport. For detail of the program, please visit the program webpage at:

https://www.epd.gov.hk/epd/english/environmentinhk/air/guide_ref/remote_sensing_Petrol_n_LPG.html

 

 

Promoting Better Vehicle Maintenance

Training and seminars on vehicle maintenance

Since August 1999, the EPD, in collaboration with the Vocational Training Council and other organisations had been offering training sessions for vehicle mechanics on proper engine repair and maintenance to reduce emissions from vehicles. At present, vehicle maintenance courses are still being offered by the Vocational Training Council for vehicle mechanics.

Since September 2014, the EPD has been deploying roadside remote sensing equipment to measure the exhaust emissions from LPG and petrol vehicles. Excessively emitting vehicles identified have to pass a chassis dynamometer based emission test to confirm that they meet the emission limits. To help the vehicle mechanics to get familiar with the new emission test, technical seminars and demonstration tests have been organised to explain the technical details. The EPD has also commissioned the Vocational Training Council to deliver free short courses to the trade teaching the technique of maintaining the LPG and petrol vehicles to pass the chassis dynamometer based emission test.

 

 

Promoting Electric Vehicle Adoption

As electric vehicles (EV) have no tailpipe emissions and low carbon emission, the Government has been actively promoting EV adoption and has formulated a series of policies and measures. In March 2021, the Government announced the first Hong Kong Roadmap on Popularisation of Electric Vehicles, which will guide Hong Kong’s future direction to the target of zero vehicular emissions early. For details, please see Promotion of Electric Vehicles in Hong Kong.

 

 

Vehicle Emission Inventory for Local Vehicles

A comprehensive understanding of motor vehicle emissions from road transport enables the EPD to formulate targeted policies and measures for reducing vehicle pollutants effectively. To achieve this, the vehicle emission inventory for local vehicles is compiled annually as a critical component among others of the broader Hong Kong Air Pollutant Emission Inventory, which tracks the amount of air pollutant emissions from all major sources across Hong Kong.

To ensure robust inputs for the vehicle emission inventory, the EPD gathers information through various methods. A cornerstone of this effort is the use of Portable Emission Measurement Systems (PEMS) to capture real-world tailpipe emissions from a representative sample of in-use vehicles. Globally recognized as a standard for accuracy, PEMS provides dynamic emission data under diverse driving conditions, addressing limitations of the standardised driving conditions of laboratory testing. By using emission factors derived from PEMS measurement data alongside with the traffic data collected from other sources, the EPD estimates the vehicle emission inventory with reasonable accuracy. This data-driven approach not only quantifies total air pollutant emissions from road transport but also evaluates the efficacy of existing emission control measures, ensuring robust adaptive and evidence-based policymaking.

The PEMS installation on a coach for real-world vehicle emission measurements

The PEMS equipment installed inside a coach for real-world vehicle emission measurements

 

 

 

Roadside Air Quality Trends

The above measures have brought a significant improvement of roadside air quality. Compared with 1999, the concentrations of major air pollutants recorded at the roadside air quality monitoring stations have been on a declining trend in 2024: the annual average concentrations of respirable suspended particulates (RSP), fine suspended particulates (FSP), NO2, and sulphur dioxide (SO2) have dropped by 66%, 63%, 34% and 89% respectively. Although NO2 concentration at the roadside has dropped by about 47% from its peak in 2011, it is still at a high level, and the annual average concentration exceeds the respective annual Air Quality Objective. This remains a key challenge we need to tackle.

To further improve roadside air quality and tackle the NO2 problem, we have embarked on additional vehicle emission control measures including the phasing out Euro IV DCVsstrengthening the emission control of petrol and LPG vehicles through the deployment of roadside remote sensing equipment and chassis dynamometers for emission testing. The Government is also actively promoting electric vehicle adoption in Hong Kong.