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 quantity of local air pollutant emissions and their major emission sources, which helps formulate an effective 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.

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 fume, construction dust and quarry production.

Biomass burning refers to the emission activities that involve the burning of vegetation.  In Hong Kong, the only contributing source in this sector is hill fires, which can produce a large amount of particulates.



Emission Inventory for 2015

The diagram below shows the emission inventory for 2015 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 2015 Emission Inventory

See Data

Topics of Interest

Emission Trends (1997-2015)
Sectoral Analysis (1997-2015)
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 (1997-2015)

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 (1997-2015)

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 1997-2015 Emission per Capita

See Data


Changes in Emissions Relative to Energy Consumption

Chart for 1997-2015 Emission per Energy Consumption

See Data


Changes in Emissions Relative to Economic Growth

Chart for 1997-2015 Emission per GDP

See Data



Emission Reduction Plan up to 2020

Improving regional air quality in the Pearl River Delta (PRD) Regionnote1 has been one of the key areas in environmental collaboration between Hong Kong and Guangdong.  The two governments endorsed the emission reduction targets/ranges up to 2020 at the 12th meeting of Hong Kong-Guangdong Joint Working Group on Sustainable Development and Environmental Protection held in November 2012.

Both sides started the 2015 Mid-term Review Study on air pollutant emission reduction in the PRD region and the Study on Finalising the Emission Reduction Targets for 2020 in order to assess the emission reductions in the PRD region for 2015 and conclude the emission reduction targets for 2020.  It is expected that the studies will be completed around mid-2017.

Assessment results for 2015

Hong Kong fully met the 2015 emission reduction targets for the four major pollutants including SO2, NOx, RSP and VOC. The emission reductions for these pollutants in 2015 ranged from 14% to 45% as compared with the emissions in 2010.

Table 1. Emission reduction results for Hong Kong in 2015.
Pollutant Emissions (Tonnes)§ Actual Emission Reduction in 2015# 2015 Emission Reduction Targets
2010 2015
SO2 35,480 19,540 -45% -25%
NOx 107,150 91,700 -14% -10%
RSP 6,770 5,430 -20% -10%
VOC 31,020 26,610 -14% -5%

§ All emission figures are rounded to the nearest ten.

# Reductions are relative to 2010 emission levels.


Emission reduction ranges for 2020

To achieve the emission reduction targets for Hong Kong in 2020, we have undertaken a number of enhanced measures with focus on the control of local pollution sources in recent years, which are explained in the ensuing paragraphs.

On reducing local vehicular emissions, we will continue to implement the incentive-cum-regulatory scheme to progressively phase out some 82 000 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 about 1 100 Euro II and Euro III franchised buses with selective catalytic reduction devices and start tightening in stages the emission standard of newly registered vehicles to Euro VI from 1 July 2017.

On reducing vessel emissions, we introduced new regulations to cap the sulphur content of locally-supplied marine light diesel at 0.05 per cent in 2014 and mandate ocean-going vessels to switch to low sulphur fuel (with sulphur content not exceeding 0.5%) while at berth in 2015.  In December 2015, the Ministry of Transport of the Mainland issued an Action Plan to establish three domestic emission control areas (DECA) including waters in the Pearl River Delta (PRD), the Yangtze River Delta, and the Bohai Rim (Beijing, Tianjin, Hebei).  The Governments of Guangdong and Hong Kong will jointly promote the establishment of a DECA in the PRD waters to regulate emissions from marine vessels.

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 the statutory emission caps imposed via TM.  Besides, we will prepare for controlling the volatile organic compounds in fountain solutions and printing machine cleansing agents.

The above measures will help us to achieve the emission reduction targets for 2020 (Table 2) and to meet broadly the current Air Quality Objectives by 2020.

Table 2. Emission reduction ranges for 2020.
Pollutant 2020 Emission Reduction Range§ (%)
SO2 -35% ~ -75%
NOx -20% ~ -30%
RSP -15% ~ -40%
VOC -15%

§ Relative to 2010 emission levels

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

2015 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 and Zhaoqing.


User review date: 
Tuesday, 16 June, 2015