(CNN) -- World record holder Haile Gebrselassie has again ruled out competing in the marathon at the Beijing Olympics, telling a Spanish newspaper that he would be "committing suicide" by running in unfavorable conditions.
Gebrselassie is the highest profile athlete to voice fears about Beijing conditions.
Gebrselassie, who suffers from asthma, told El Pais that he would instead try to qualify for the Ethiopian team in the shorter 10,000 meters track event. He was Olympic champion over the distance in Atlanta and Sydney.
His decision comes a day after the International Olympic Committee (IOC) announced that it would consider postponing events at the Games such as the marathon if they felt conditions were unsafe.
"I have no intention of committing suicide in Beijing," Gebrselassie was quoted.
"I know that several other athletes are starting to have doubts about this.
"It's purely a personal decision that I have taken to protect my health. I do not want to endanger my future. I do not want to kill myself in Beijing.
"The marathon will be impossible because of the pollution, heat and humidity."
Gebrselassie added that he would attempt to finish his career with victory in the marathon at the London Olympics in 2012 when he would be 39.
Concerns about pollution led the IOC medical commission to hire independent experts to conduct a study into air quality.
They concuded that heat and humidity would pose just as big a threat to long distance athletes.
"We find that the competitions, although not necessarily under ideal conditions at every moment ... will be good for athletes to compete during the Beijing Games."
However, the IOC's commission conceded there will be some risk to competitors in endurance events "that include minimum one hour continuous physical efforts at high level - urban road cycling, mountain bike, marathon, marathon swimming, triathlon and road walk."
And the risk is deemed high enough for the IOC to begin working on "procedures which will allow a 'plan B' to be activated for such events if necessary."
The 34-year-old Gebrselassie holds the world marathon record of two hours four minutes and 26 seconds. E-mail to a friend