Athletic Chief denies high air pollution levels caused marathon runners to collapse 2006-02-14 HKT 05:11 The Amateur Athletic Association has dismissed criticism that high air pollution levels during the Hong Kong marathon may have caused some runners to collapse. Chairman, William Ko, said it would conduct a full review with the government to see if new guidelines were needed for next year's race. But he stressed that air quality was considered safe for the event. Two men who collapsed during the race remain in critical condition. They were among more than 20 runners sent to hospital.