You have probably heard a lot about the air quality in Hong Kong. Perhaps you even have some ideas about how it can be improved. But have you ever thought about the science behind air quality?
Air quality is a measurement of the make-up of the air we breathe. Urban air quality depends on factors such as cars, ships, aeroplanes and industry, as well as chemical reactions and wind. So, it's very complicated. To make progress, different scientists need to propose theories, but measurements and state-of-the-art computer models are also needed. And one solution may not suit every problem, as air quality varies greatly from the top of Ngong Ping to the congested streets of Causeway Bay.
Computer modelling is one of the best tools for understanding and predicting urban air quality. It has been most successful on the regional scale, such as Pearl River Delta models for Hong Kong.
But on smaller scales, models can't be made, as the computational demands are enormous. In the future, computer modelling of street-level air quality may become common. Many scientific advances will be needed to achieve this, but the result will really benefit our lives.