Author: Antonio Da Roza

Date: 12/8/10

Ozone (O3), a major constituent of photochemical smog, is formed by a series of complicated photochemical reactions of oxygen, NOx and volatile organic compounds in the presence of sunlight and warm temperature. [1]

Summer temperatures, direct sunlight and a standing air layer contribute to high ozone concentrations. [2]


  1. ‘Air Quality Objectives Review Public Consultation’, Environmental Protection Department Hong Kong, July 2009 - last accessed 5/8/10
  2. FAQ air pollution, (2009). Lenntech BV - last accessed 7/8/10