Paula Radcliffe believes Beijing's heat and humidity will be more of a threat at the Olympics this summer than the Chinese capital's pollution.
Beijing's air quality has been flagged up as a potential problem for athletes in endurance events like the marathon.
But Radcliffe, who has asthma, believes the risks have been exaggerated.
"I need the right dosages of my asthma medication but after that I don't think it's something you can worry about too much," Radcliffe told BBC Sport.
"It might not even be as bad as everyone thinks because I'm sure the Chinese will do everything they can to reduce the problem.
"Beijing will be a cleaner Games than Athens and Sydney - we're going in the right direction"
"Will I really care if I wake up the next morning with a sore throat and feeling a bit sick if I have got what I want the day before? No, probably not.
"We're all dealing with the same thing so I don't think worrying about it in advance is that productive.
"But heat and humidity are a different kettle of fish because they are things you can prepare for. I'm concentrating more on those factors than the pollution."
Radcliffe's comments follow confirmation last month that Ethiopian great Haile Gebrselassie, the men's world record-holder for the marathon, will not run the distance in Beijing as he is worried about his asthma.
And Justine Henin, the defending Olympic tennis champion, is another asthmatic unwilling to risk her health in Beijing.
606: DEBATE
But Radcliffe, who holds the women's marathon world record, is determined to add an Olympic gold to her remarkable haul of medals, records and big-race victories.
The 34-year-old English star has won golds at every other major championship - over a variety of distances and surfaces - but an Olympic medal of any colour has eluded her.
Sprinted out of track medals in 1996 and 2000, Radcliffe was the favourite for marathon gold in 2004 but quit, in some distress, with six kilometres left - a bad reaction to anti-inflammatory drugs she was taking for a leg injury had left her unable to absorb fuel.
"When I was a little girl it was always the Olympics that I thought of as the pinnacle," said Radcliffe, who was speaking at the launch of Nike's latest running aid, the Nike+SportBand.
"So an Olympic gold would be right up there in my list of achievements - it's the one you really want to win.
"I haven't been able to do that yet but, fingers crossed, I've got a good chance this year - probably my best shot.
"You can't overstress about it but I want to make sure everything is 100% for Beijing."
It was with this in mind that Radcliffe, who took most of 2006 and 2007 off to have a child, reluctantly withdrew from this weekend's London Marathon, a race she has contested and won three times.
A nagging toe injury was to blame for that decision but Radcliffe, who has been back in full training for the last two weeks, is certain there will be other opportunities to run marathons in London again, not least at the 2012 Games.
"In terms of goals, I want to win another world title and I want to run faster. On the right day in the right conditions, I believe that's possible," she said.
"But I also want to perform at another Olympics and running in London would be incredible. The atmosphere, the memories and the pride at representing your country in Britain will be so special.
"I want to carry on for that. I'm not sure my legs will hold out for 2016, though!"
Radcliffe is probably right about that but anybody who saw her winning performance at last year's New York Marathon - her first race over that distance since the birth of her daughter Isla - will have a sneaky suspicion she might just do it.
But as well as being confident of her 2012 chances, Radcliffe is also optimistic about her sport's fight against doping.
"I wouldn't say it's a completely level playing field just yet, but we're getting closer," she said.
"Beijing will be a cleaner Games than Athens and Sydney. We're going in the right direction."
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