Data & Statistics

Hong Kong Air Pollutant Emission Inventory

The Environmental Protection Department (EPD) compiles the Hong Kong Air Pollutant Emission Inventory annually to analyze the quantity of local air pollutant emissions and their major emission sources for supporting the formulation of effective air quality management strategies in Hong Kong. It also provides necessary data for carrying out air quality impact assessments. The emission inventory for Hong Kong was first published on EPD's website in March 2000.

The emission inventory comprises estimates of 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 hill fires.

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, from which only VOC, RSP and FSP emissions are significant.  In this category, the major emission sources for VOC include paints and associated solvents, consumer products and printing, whereas those for RSP and FSP include paved road dust, cooking fumes, construction dust and quarry production.

In Hong Kong, hill fires are one of the sources of particulates. As most of the hill fires in Hong Kong are caused by human negligence or accidents and are sporadic in nature, their emissions cannot be reduced through emission control measures like other pollution sources.  In order to enable more meaningful comparison on the emission trends of controllable pollution sources and the effectiveness of local emission control measures, hill fires are reported separately in Sectoral Analysis.



2017 Emission Inventory

The diagram below shows the emission inventory for 2017 under different emission source categories including public electricity generation, road transport, navigation, civil aviation, other combustion sources and non-combustion sources.

Chart of 2017 Emission Inventory

See Data

Topics of Interest

Emission Trends (2001-2017)
Sectoral Analysis (2001-2017)
Changes in Emissions Relative to Population, Energy Consumption and Economic Growth
Update of Emission Inventory
Emission Inventory Report
Useful References



Emission Trends (2001-2017)

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 (2001-2017)

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 "Hill Fires"



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

Changes in Emissions Relative to Population

Chart for 2001-2017 Emission per Capita

See Data


Changes in Emissions Relative to Energy Consumption

Chart for 2001-2017 Emission per Energy Consumption

See Data


Changes in Emissions Relative to Economic Growth

Chart for 2001-2017 Emission per GDP

See Data



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, VOC-containing products and solvent usage for coatings, and survey data for marine paints to assess emissions from VOC-containing products.


Emission Inventory Report

2017 Hong Kong Air Pollutant 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)






User review date: 
Tuesday, 16 June, 2015