General air quality in Hong Kong has improved in the past few years according to the Environmental Protection Department's just-released report, Air Quality in Hong Kong 2013.
Data was collected from 11 general and three roadside air monitoring stations.
The ambient levels of nitrogen oxides (NOx), sulphur dioxide (SO2) and respirable suspended particulates (RSP) have been reduced in recent years, due joint control efforts by the governments of Hong Kong and Guangdong to cut emissions in the Pearl River Delta region, the department says.
However, the concentration of ozone - a major constituent of photochemical smog - is rising slowly. The two governments will continue to implement control measures to alleviate the problems.
Targeted control measures are also being introduced to reduce the increasing trend of roadside nitrogen dioxide (NO2).
Concentration levels of carbon monoxide and lead remained comparatively low, as do those of toxic air pollutants.
View the full report here.