AIR POLLUTION CONTROL STRATEGIES Air Quality Objectives Mobile Pollution Sources Stationary Pollution Sources Regional Smog Problem Co-operation between Guangdong and Hong Kong Enhanced Air Pollution Control Measures in Hong Kong Emissions Reduction by Guangdong Regional Smog Problem The pollutants generated by vehicular emissions as well as industrial and commercial operations in PRD have an adverse impact on the air quality on the whole region. Under sunlight, these pollutants undergo photochemical reactions to form ozone and smog. The regional smog problem is especially serious when weak northerly wind prevails in the PRD area or when the region is under the influence of subsiding air at the periphery of a typhoon because the ambient air pollutants in the PRD cannot be dispersed effectively under such conditions. Smog problem is at its worse when the sun is high, hence high levels of ozone are observed usually around midday. Over the past decade, the regional smog problem has been worsening as reflected by the deterioration in visibility. [Trends of Visibility Impairment in Hong Kong]

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Last revision date: 05 June 2006

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