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.


Overview of 2022 Emission Inventory

In 2022, the total emissions of major air pollutants in Hong Kong were 4 390 tonnes of SO2, 50 010 tonnes of NOx, 2 840 tonnes of PM10, 2 220 tonnes of PM2.5,  21 130 tonnes of VOC and 54 850 tonnes of CO, respectively. 

In 2022, emissions of SO2, NOx, VOC and CO decreased by 4% to 7% as compared to 2021 while PM10 and PM2.5 slightly increased by 1% to 3% due to increased construction activities. 

2022 Emission Inventory

The diagram below shows the quantities and distribution of the major air pollutants in Hong Kong in 2022. 


2022 Emission Inventory


Emission Inventory Report

2022 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)