Air pollution has become the most serious environmental problem for Hong Kong, affecting not only public health but also the city's ability to attract and retain foreign investments. There is an urgent need to devise and implement a comprehensive air quality action plan to improve Hong Kong's air quality. This comparative research analyses air quality management (AQM) issues in two jurisdictions which are world-leaders in fighting air pollution: London and Los Angeles. It has two core objectives. Firstly, to provide standards against which Hong Kong's air quality problem and policies can be assessed. Secondly, to identify solutions implemented in other jurisdictions that can be successfully adapted to Hong Kong to improve air quality. As such, this research focuses on two main questions: how do we compare with other world-cities, and what can we learn from them.