By: Jessica Hefes

Date: 9/8/10

It has been observed that athletes who have been exercising in polluted conditions will show reduced performance after two or three days. Given how high Hong Kong’s air pollution levels have reached in recent years, there have only been approximately 30 days out of the year in which it is truly safe to exercise. [1]


A jogger during Hong Kong's sandstorm episode (22/3/10) - Alex Hofford (

Studies have shown that there are significant negative interactions between regular exercise and nitrogen dioxide, particulate matter and ozone for all-cause cardiopulmonary mortality. Significant effects of ambient nitrogen dioxide, particulate matter and ozone on mortality were found in groups who did not exercise regularly, but not in the group that did. [2]

Health impact of pollution depends on the concentrations at which air pollutants are inhaled, as well as the duration of exposure. Therefore transport presents the greatest exposure risk for some pollutants even if total emissions are higher from the power sector. [3]


  1. FAQ, Pollution and health, Hedley Index - last accessed 9/8/10
  2. Does regular exercise protect against air pollution-associated mortality?,Wong CM, Ou C-Q, Thach T-Q et al, 2007, Prev Med 44:386–392
  3. Air Pollution: costs and paths to a solution, Department of Community Medicine, HKU, Department of Community and Family Medicine, CUHK, Institute for the Environment, HKUST, Civic Exchange, June 2006 - last accessed 5/8/10