- 9 -
Air quality report for December
The Environmental Protection Department today (Monday) released air quality information for last month.
A spokesman for the department said the purpose of the announcement was to keep the public informed of the air quality levels in the territory and to explain the measurements. The announcement contains monitoring results from Mong Kok, Central/Western and Kwai Chung, which represent three important land use types in the territory:
locations close to road traffic in built-up urban areas; combined commercial and residential districts; and districts close to industrial areas.
The department currently monitors air quality continuously at eight stations, including the three mentioned. Short-term measurement exercises are also undertaken as and where the need arises.
The reported air pollutants include sulphur dioxide (SO2), nitrogen dioxide (NO2), total suspended particulates (TSP) which comprise all sizes of dust particles. and the respirable fraction of the dust (RSP). All these pollutants can affect respiratory health in sufficient concentration.
In December there were no exceedances of the Air Quality Objectives at any of the three stations, but the highest concentrations of air pollutants were recorded at Mong Kok.
Continued road works at Mong Kok Road have increased pollutant levels at the monitoring station. Traffic management changes near the station also contributed to the increase of measured pollutants.
Low wind speeds and sunny conditions on December 23 allowed NO2 levels to build up in the urban areas, while significant rainfall on the following two days kept dust levels low.
SO2 is
The gases and particles described originated from various sources. mostly produced when fuels that contain sulphur are burned. NO2 is formed during combustion by the combination of nitrogen and oxygen, and by the atmospheric oxidation of nitric oxide (NO), also a product of combustion.
Page 10Page 11