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Air Quality Health Index may reach "Serious" level

     The general and roadside monitoring stations of the Environmental Protection Department (EPD) have recorded a higher than normal pollution level. At 2pm today (September 25), the Air Quality Health Index (AQHI) at several general monitoring stations reached 8 or above and all three roadside monitoring stations reached 8. The health risk category is "Very High".

     The coast of Guangdong and the Pearl River Delta (PRD), including Hong Kong, are under the influence of a continental airstream with sunny periods. In Hong Kong, the wind is light. The intense sunshine has enhanced photochemical smog activities and the formation of ozone in the PRD region. The ozone is also being accumulated due to light winds, resulting in higher pollution levels. In addition, light winds in the urban areas, which have hindered the effective dispersion of the pollutants at street level, coupled with a high ozone level in the general air, have led to a higher than normal nitrogen dioxide level. As it is likely that the air pollutants will continue to accumulate in the territory, the EPD forecasts that the AQHI at some of the general and roadside monitoring stations could reach "Serious" level later today.

     According to the Observatory, an anticyclone aloft over southern China will strengthen gradually in the next couple of days, bringing generally fine weather to the region. It is expected that the pollution due to photochemical smog activities will still be active, resulting in very high or serious AQHIs in the afternoon during this period.

     With an AQHI in the "Very High" range or above, children, the elderly and persons with existing heart or respiratory illnesses are advised to reduce physical exertion and outdoor activities to a minimum or avoid such activities. The general public are advised to reduce, or reduce to a minimum, outdoor physical exertion, and to reduce time outdoors, especially in areas with heavy traffic. As the health effects of air pollutants may vary for individuals, persons who are in doubt or who experience discomfort should seek advice from health care professionals. The public may visit the Centre for Health Protection's website ( for more information on health effects of air pollution and relevant health advice.

     The Education Bureau (EDB) urges all schools to visit the EDB website for appropriate measures to safeguard students' health and take note of changes in the index. The relevant hyperlink is as follows:

     At the "Very High" level, employers of outdoor workers performing heavy manual works are advised to assess the risk of outdoor work and take appropriate preventive measures to protect the health of their employees, such as reducing outdoor physical exertion and the time of their stay outdoors, especially in areas with heavy traffic. At the "Serious" level, employers of all outdoor workers are advised to assess the risk of outdoor work and take appropriate preventive measures to protect the health of their employees.

     Members of the public can check the current AQHI readings at the EPD's website ( or by calling the hotline 2827 8541.

Ends/Thursday, September 25, 2014
Issued at HKT 15:39


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