Clean Air and You
You may also visit the following links for more information.
EPD - Clean Air and You: http://www.epd.gov.hk/epd/english/environmentinhk/air/prob_solutions/clean_air_you.html
HKO - Cool Met Stuff: https://www.youtube.com/playlist?list=PLBdhEGSPvUGVuK7fZUxHKzv51Y_2hy_hW(only available in Chinese)