Data & Statistics

Hong Kong Air Pollutant Emission Inventory

The Environmental Protection Department (EPD) compiles the Hong Kong Air Pollutant Emission Inventory every year to analyze the air pollution condition and the major emission sources which helps formulate the air quality management strategy in Hong Kong.  The emission inventory for Hong Kong was first uploaded to EPD’s website in March 2000.

The emission inventory comprises estimates of the emissions from seven source categories for six major air pollutants, namely: sulphur dioxide (SO2), nitrogen oxides (NOx), respirable suspended particulates (RSP or PM10), fine suspended particulates (FSP or PM2.5), volatile organic compounds (VOC) and carbon monoxide (CO). The emission sources include public electricity generation, road transport, navigation, civil aviation, other combustion sources, non-combustion sources, and biomass burning.  Starting from this year, emission inventory of biomass burning has been added to improve the coverage of local emission inventory.

Other combustion sources are defined as sources involving combustion, other than public electricity generation, road transport, navigation and civil aviation.  Major contributing sources in this sector include non-road mobile machineries operating in construction sites and container terminals.

Non-combustion sources are defined as those remaining sources that do not involve combustion and only VOC, RSP and FSP emissions are significant.  Under this category, the major sources for VOC include paints and associated solvents, consumer products and printing, whereas those for RSP and FSP include paved road dust, cooking fume, construction dust and quarry production.

Biomass burning is the burning of living and dead vegetation mainly due to human activities.  In Hong Kong, the only contributing source in this sector is emissions from hill fires which can produce a large amount of particulates.



Emission Inventory for 2014

The diagram below shows the emission inventory for 2014 under different emission source categories including public electricity generation, road transport, navigation, civil aviation, other combustion sources, non-combustion sources, and biomass burning.

Chart of 2014 Emission Inventory

See Data

Topics of Interest

Emission Trends (1997-2014)
Sectoral Analysis (1997-2014)
Changes in Emissions Relative to Population, Energy Consumption and Economic Growth
Emission Reduction Plan up to 2020
Update of Emission Inventory
Emission Inventory Report
Useful References



Emission Trends (1997-2014)

Trends of Emissions from Specific Source Categories


Legend for Emission Trends

icon for Chart of SO2 Emission

Sulphur Dioxide (SO2)

icon for Chart of NOx Emission

Nitrogen Oxides (NOx)

icon for Chart of RSP Emission

Respirable Suspended Particulates (RSP)

icon for Chart of FSP Emission

Fine Suspended Particulates (FSP)

icon for Chart of VOC Emission

Volatile Organic Compounds (VOC)

icon for Chart of CO Emission

Carbon Monoxide (CO)



Sectoral  Analysis (1997-2014)

Sectoral Analysis for Specific Source Categories

Emission from Public Electricity Generation

Sectoral Analysis for "Public Electricity Generation"


Emissoins from Road Transport

Sectoral Analysis for "Road Transport"


Emissions from Navigation

Sectoral Analysis for "Navigation"


Emissions from Civil Aviation

Sectoral Analysis for "Civil Aviation"


Emissions from Other Combustion Sources

Sectoral Analysis for "Other Combustion Sources"


Emission from Non-combustion Sources

Sectoral Analysis for "Non-combustion Sources"


Emission from Biomass Burning

Sectoral Analysis for "Biomass Burning"



Changes in Emissions Relative to Population, Energy Consumption and Economic Growth

Changes in Emissions Relative to Population

Chart for 1997-2014 Emission per Capita

See Data


Changes in Emissions Relative to Energy Consumption

Chart for 1997-2014 Emission per Energy Consumption

See Data


Changes in Emissions Relative to Economic Growth

Chart for 1997-2014 Emission per GDP

See Data



Emission Reduction Plan up to 2020

The Hong Kong SAR and Guangdong Provincial Governments have long been collaborating to improve air quality in the Pearl River Delta (PRD) Regionnote1 . Over the past years, the two Governments significantly reduced the emissions of four major pollutants, namely SO2, NOx, RSP and VOC.  At the meeting of Hong Kong-Guangdong Joint Working Group on Sustainable Development and Environmental Protection held in November 2012, both sides endorsed a new set of emission reduction targets / ranges up to 2020, using 2010 as the base year. Both sides have been implementing additional pollution control measures on this basis for bringing continuous improvement to the regional air quality.

To achieve continuous improvement of the air quality, a series of emission reduction measures are being implemented. On reducing vehicular emissions, we will continue to phase out progressively the pre-Euro IV diesel commercial vehicles by the end of 2019, strengthen the emission control of petrol and liquefied petroleum gas vehicles using roadside remote sensing equipment, subsidise the franchised bus companies to retrofit the Euro II and Euro III franchised buses with selective catalytic reduction devices and prepare for tightening vehicular emissions standards to Euro VI for newly registered vehicles.

On reducing vessel emissions, we have introduced new regulations to cap the sulphur content of locally-supplied marine light diesel at 0.05 per cent. We will mandate ocean-going vessels to switch to low sulphur fuel (with sulphur content not exceeding 0.5%) while at berth in 2015.  By that time, Hong Kong will become the first port in Asia to mandate the fuel switch at berth. We are also collaborating with the mainland authorities to implement measures to reduce vessel emissions in the waters of the Pearl River Delta, with a view to taking forward the fuel switch of ocean going vessels while at berth in the short run and establishing an emission control area in the long run.

On reducing emissions from power plants, we will continue to require the power plants to adopt the best practicable means to reduce emissions and use more natural gas for electricity generation so as to meet our emission caps imposed on power sector. Besides, we will continue to collaborate with the Guangdong authorities to further improve the regional air quality.

Such measures will help us to achieve the emission reduction targets for 2020, and to meet broadly the existing Air Quality Objectives by 2020.

The changes in emissions in 2014 compared with emissions in 2010 in Hong Kong are shown in the following table:

  Pollutant   2010 Emission (Tonnes)  2014 Emission (Tonnes)  Change in Emission 2010-2014

 2015 Reduction Target (Reference to 2010)

SO2 35,490 31,710 -11% -25%
NOx 108,500 109,570 +1% -10%
RSP 6,750 5,900 -13% -10%
VOC 31,560 27,020 -14% -5%

Note: Emission figures are presented in the nearest ten.

Compared with the base year of 2010, SO2, RSP and VOC emissions in 2014 decreased by 11% to 14%, while NOx emissions slightly increased by 1%.  In the coming year, the power plants would be required to use more natural gas in power generation in order to meet the tightened emission caps set out in the Second Technical Memorandum.  We expect that the emissions of SO2 and NOx will be reduced substantially in 2015.


Update of Emission Inventory

Making reference to international developments and technological advancement, we have been updating the methodologies to compile emission inventories including the collection of most updated data with an aim to provide a better support to the management of air quality.  Whenever the compilation methodology is updated, new activity data are collated, or errors in the estimates are identified, we will follow international practice to update the emission inventory and to revise the emission inventories for past years as far as practicable based on the updated methods and data to enable consistent and reliable emission trend analysis to be made. Updates of the emission inventories are listed in the Summary of Updates to the Emission Inventory.  Major updates to the emission inventories in recent years are highlighted below.

  • EPD commissioned a comprehensive study on the marine emission inventory in 2008, which was completed in 2012.  The study collected extensive local vessel activity data and reviewed the latest emission compilation methodologies of advanced places such as the Port of Los Angeles of the USA.  The study concluded that these latest emission compilation methodologies can provide more realistic estimates of marine emissions.  Based on the study findings, we updated the previous emission inventories for marine vessels. The updated emissions from vessels were higher than the previous ones.
  • EPD have been conducting emission measurements for on-road vehicles by means of remote sensing equipment and advanced portable emission measurement systems (PEMS).  The measurements have provided a more robust basis for us to estimate vehicle emissions.  They have also found that vehicles with inadequate maintenance, e.g. LPG vehicles with worn-out catalytic converters, could emit considerably above their normal levels.  We made use of the findings to update our vehicle emission estimation model and compile the vehicle emission inventory.
  • Since the implementation of the Air Pollution Control (Volatile Organic Compounds) Regulation in April 2007, we have used the sales report data submitted by importers under the Regulation to compile VOC emissions of regulated products including six types of consumer products (air fresheners, hairsprays, multi-purpose lubricants, floor wax strippers, insecticides and insect repellents), printing inks and architectural paints.  In October 2009, we amended the Regulation to further regulate the VOC contents of vehicle refinishing paints, marine paints (vessels and pleasure craft paints), adhesive and sealants and started to compile the VOC emissions from these paints based on their sales report data. Emissions from cleansing solvents during the application of paints have also been estimated.  To compile VOC emissions for the regulated products, we also made reference to EPD’s studies on printing industry, solvent usage for coatings and VOC-containing products, and survey data for marine paints to assess emissions from VOC-containing products.



Emission Inventory Report

2014 Hong Kong Emission Inventory Report

Useful References

Intergovernmental Panel on Climate Change (IPCC)
U.S. Environmental Protection Agency (U.S. EPA - AP42)
European Environment Agency (EEA - EMEP/EEA Emission Inventory Guidebook)
Census and Statistics Department (C&SD - Hong Kong Statistics)
Electrical and Mechanical Services Department (EMSD - Hong Kong Energy End-use Data)


1 PRD Region refers to the whole territory of HKSAR and the Pearl River Delta Economic Zone (PRDEZ). PRDEZ includes Guangzhou, Shenzhen, Zhuhai, Dongguan, Zhongshan, Foshan, Jiangmen, Huizhou (Huicheng, Huiyang, Huidong, Boluo), and Zhaoqing (Duanzhou, Dinghu, Gaoyao, Sihui).


User review date: 
Tuesday, 16 June, 2015