(AP) -- The Beijing smog made it so difficult for beach volleyball star Misty May-Treanor to breathe when she arrived for the 2008 Olympics that she wasn't sure she would be able to compete.

"I was like, 'Oh, my God. My asthma's back from when I was a kid,'" she said recently after taping a public service announcement for a campaign to help people with nasal allergies. "It was actually allergies. My allergies kicked in there because of the smog, and it turned into a chest cold."

May-Treanor and her partner, Kerri Walsh, went on to win the gold medal - their second straight Olympic championship.

And when May-Treanor was approached about helping out the "Ditch the Drip" campaign to fight nasal allergies, she jumped at it.

"I was like, 'Oh, sure. Let me tell you a story,'" she said, thinking back to Beijing. "It just inhibited my breathing. You're exercising; you're coughing, wondering what happened. I hate it."

May-Treanor and Walsh are in Brazil this weekend for the start of the international beach volleyball tour season. They are well on their way to qualifying for the Olympics in London, where the wet weather is expected to help those with allergies.

But back home, it's another story.

"They're estimating that this allergy season is going to be a bad one," May-Treanor said.

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