Pollution levels were too high for the staging of the Standard Chartered Marathon last Sunday and runners should have been advised against taking part, international experts say.
Organisers of the marathon last week said they may ask runners to submit a sports history following the death of a runner days after taking part in the race. Tsang Kam-yin, 53, died on Tuesday after collapsing on the Tsing Ma Bridge, 13km into the race.
Professor Robert McConnell, of the University of Southern California's Keck school of medicine, said that while no benchmarks existed on when an event such as a marathon should be cancelled, he would not have recommended running at the levels of pollution last Sunday.
The air pollution index reached a 'very high' 149 in Causeway Bay on the day and 147 in Central.
Dr Antonio Miguel of the University of California's Institute of the Environment said he would not recommend exercising outdoors at such high pollution levels.
Professor James Sharman, of the University of Queensland's faculty of health sciences, agreed, saying that as a jogger himself, he would not run in such conditions.