The Environmental Protection Department compiles on an annual basis emission inventory of Hong Kong providing estimates of annual emissions of five major air pollutants, namely: sulphur dioxide (SO₂), nitrogen oxides (NOx), respirable suspended particulates (RSP or PM₁₀), volatile organic compounds (VOC) and carbon monoxide (CO).

Emission inventory data are used for developing air quality control strategy, gauging emissions trends, identifying emission levels from different pollution sources and supporting air quality modelling.

The diagram below shows the emission inventory for 2006 under different source categories including public electricity generation, road transport, navigation, civil aviation, other fuel combustion sources and non-combustion sources.

Changes in Emission Relative to Population, Energy End-use and Economic Growth

See Data

 

The HKSAR Government reached a consensus with the Guangdong counterpart in April 2002 to reduce, on a best endeavour basis, the emissions of sulphur dioxide (SO₂), nitrogen oxides (NOx), respirable suspended particulates (RSP) and volatile organic compounds (VOC) in the Pearl River Delta (PRD) Region^note1 by 40%, 20%, 55% and 55% respectively by 2010, using 1997 as the base year.

Our progress in 2006 is shown in the following table. Except for SO₂, Hong Kong has achieved steady progress in reducing emissions. The increase in SO₂ emission was due to a rise in the use of coal in power generation in recent years.

To achieve the emission reduction targets in 2010, a series of additional control measures will be implemented in the coming years. For instance, the wider use of natural gas, retrofitting flue gas desulphurization units, retrofitting low NOx burner and selective catalytic convertor will be implemented in power plants to reduce the SO₂, NOx and RSP emissions. We are also considering to replace industrial diesel with ultra-low sulphur diesel to further reduce the SO₂ emission from the industrial and commercial sections. Regulation introduced in 2007 to limit the VOC contents of selected consumer products, paints and printing inks in phases, as well as controlling the emissions from certain printing machines will help to achieve the emission reduction targets. Other measures will be implemented to reduce emissions from vehicles.

Following international practice, the emission inventory will be updated when methods are changed or refined or when better emission factors are available. In addition, the emission inventory over a whole time series will be recalculated in order to provide comparable and consistent emission trends.

To systemize the methodology in the compilation of emission inventory in the Pearl River Delta region, an “Air Emission Inventory Handbook for Pearl River Delta Region” has been compiled in 2005. Both the Guangdong Government and Hong Kong Special Administrative Region Government have agreed to adopt the handbook in compiling their emission inventories.

Apart from the emission inventory for 2006, historic emission inventories from 1990 to 2005 have been recalculated based on the handbook.

Major changes made in the emission inventories from 1990 to 2006 are as follows:

RSP^note2 emissions from public electricity generation have been reported in lieu of particulate matters.

Emission factors of equipment in airport, container ports and construction sites have been updated.

Emission due to evaporative loss in petrol vehicles has been included.

    iv)

Emissions from tyre, brake and road surface wear have been included.

The methods to compile VOC emissions from printing industry and petrochemical terminal have been refined.

Emission factors for aircrafts have been updated.

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).

² RSP of public electricity generation is determined from TSP (Total Suspended Particulates) with the use of conversion ratio of 1 to 0.67 adopted from the USEPA's AP42 for coal-fired unit equipped with electrostatic precipitator. For combined cycle gas turbine units, the RSP/TSP ratio of 1 is adopted as the majority of particulates emitted is of aerodynamic diameter of 10 micrometer or smaller.