Air quality on Hong Kong roadsides: Statistical analysis on historical database

Population and road traffic densities in Hong Kong are among the highest in the world. As a result of increasing road traffic, vehicle emissions have become the main source of air pollution besides industrial pollution. Air pollution seriously threatens public health, economy, and social wellbeing of Hong Kong residents. Recently, the smog problem and the reduced visibility have been a pressing topic of air pollution in Hong Kong. Two types of smog, i.e., photochemical smog, and combination smog of smoke and fog, often occur in Hong Kong territory. Many districts in Hong Kong are failing to meet statutory health standards for air quality, and the associated costs to individuals, businesses and society are estimated to be in the billions of dollars each year. This study, based on historical database analysis, aims to give comprehensive reviews of smog and its impact factors including the pollutant levels, the urban conditions, and the control strategies to reduce and control major air pollutant levels in Hong Kong.