And it is hard to dismiss the cautionary tales. Tom Fleming, who won the New York Marathon in 1973 and 1975, is an experienced runner and coach. He was in Beijing twice, in 1991 and 1994, both times as coach for the United States women's ekiden team. In ekiden, a relay race popular in Asia, runners cover various distances to equal a marathon distance of 26.2 miles.
The ekiden races were in March, so heat and humidity were not severe, Tom said, but the pollution had him worried. "What I noticed was that my white shirt was gray," he said. "That's when I said, 'Holy crow.' You know it can't be good.
"Let me know if you see any Chinese people running," he added. "I never saw anyone."
That's because ordinary Beijing residents almost never run on the streets where Tom was running.
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