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 six 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 power electricity generation, road transport, navigation, civil aviation, other fuel combustion sources and non-combustion sources.

Other fuel combustion sources are defined as sources involving combustion of fuels, other than power 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 of fuels 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, construction dust, quarry production and cooking fume.


Emission Inventory for 2013

The diagram below shows the emission inventory for 2013 under different emission source categories including public electricity generation, road transport, navigation, civil aviation, other fuel combustion sources and non-combustion sources.

2013 Emission Inventory

See Data

Topics of Interest

Emission Trends (1997-2013)
Sectoral Analysis (1997-2013)
Changes in Emission Relative to Population, Energy Consumption and Economic Growth
Emission Reduction Plan up to 2020
Update of Emission Inventory
Emission Inventory Reports
Useful References


Emission Trends (1997-2013)

Trend of Emissions from Specific Source Categories

Legend for Emission Trends

Sulphur Dioxide (SO2)




Nitrogen Oxides (NOx)




Respirable Suspended Particulates (RSP)








Fine Suspended Particulates (FSP)




Volatile Organic Compounds (VOC)






Carbon Monoxide (CO)



Sectoral  Analysis (1997-2013)
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 Fuel Combustion
Sectoral Analysis for "Other Fuel Combustion"
Emission from Non-combustion Sources
Sectoral Analysis for "Non-combustion Sources"

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

1. Changes in Emission Relative to Population

Chart for 1997-2013 Emission per Capita
Legend for Emission per Capita Chart
See Data
2. Changes in Emission Relative to Energy Consumption
Chart for 1997-2013 Emission per Energy Consumption
Legend for Emission per Energy Consumption Chart
See Data

3. Changes in Emission Relative to Economic Growth

Chart for 1997-2013 Emission per GDP
Legend for Emission per GDP Chart

See Data


Emission Reduction Plan up to 2020
The Hong Kong SAR and Guangdong Provincial Governments have long been collaborating to improve the 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 base year. Both sides have been implementing additional pollution control measures on this basis for bringing continuous improvement to the regional air quality.

In order to achieve the emission targets/ranges set for 2015 and 2020, Hong Kong has implemented the following key measures:

  • Completed in April 2014 a one-off subsidy scheme to replace the catalytic convertors and oxygen sensors of petrol / Liquefied Petroleum Gas (LPG) taxis and light buses;
  • Launched in March 2014 an incentive-cum-regulatory scheme to phase out pre-Euro IV diesel commercial vehicles by end 2019;
  • Strengthened the inspection and maintenance of LPG and petrol vehicles from September 2014 by deploying roadside remote sensing equipment to detect excessive emissions from petrol and LPG vehicles;
  • Tightened the limit on sulphur content of locally supplied marine light diesel to 0.05% in April 2014;
  • Tightened progressively the emission caps on power plants, with the latest emission caps effective in 2019; and
  • Continued to enforce the Air Pollution Control (Volatile Organic Compounds) Regulation to control volatile organic compounds emission from paints, printing inks, adhesives, sealants and selected consumer products.

Other key measures in the pipeline include:

  • Mandating the use of low-sulphur fuel for ocean-going vessels berthing in Hong Kong from 1 July 2015 under the Pollution Control (Ocean Going Vessels) (Fuel  at Berth) Regulation;
  • Controlling the emissions from off-road mobile machinery from 1 September 2015 under the Air Pollution Control (Non-road Mobile Machinery) (Emission) Regulation; and
  • Retrofitting Euro II and Euro III franchised buses with selective catalytic reduction devices to reduce their emissions.

Such measures will help us to achieve the emission reduction targets for 2015 and 2020, and to meet broadly the existing Air Quality Objectives by 2020.


Changes in 2013 emissions in Hong Kong compared with 2010 emission levels range from -12 % to +4%. Details are listed in the table below:

Pollutant 2010 Emission (Tonnes) 2013 Emission (Tonnes) Change in Emission 2010-2013 2015 Reduction Target (Reference to 2010)
SO2 35,490 31,280 -12% -25%
NOx 108,360 113,220 +4% -10%
RSP 6,270 6,040 -4% -10%
VOC 32,870 29,420 -10% -5%

Note: Emission figures are presented in the nearest ten.

Compared with the base year of 2010, SO2, RSP and VOC emissions in 2013 had decreased by 4% to 12%. However, NOx emissions had increased by 4% which was due to the higher coal consumption for electricity generation and the increase in construction and aviation activities.


Update of Emission Inventory

Making reference to international developments and technological advancement, we have been updating the methodologies to compile emission inventory 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 inventory 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 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 inventory 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, paints, adhesives and sealants. In April 2012, we further regulated the VOC contents of vehicle refinishing and marine paints (vessels and pleasure craft paints) 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

2013 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