Athletes competing at the Beijing Olympics will face bigger mental issues than physical problems coping with China's pollution, Netherlands soccer coach Foppe De Haan said on Monday.
De Haan told a news conference his players had undergone a rigorous training programme to get themselves in the best physical shape to handle the heat and humidity.
But he said nothing could prepare them for the psychological challenge of playing under a thick blanket of haze.
"This is not a physical problem, this is a mental thing," he said. "I heard today that you can't see the (Beijing) stadium from 500 metres away. That's awful I think, but there is no point complaining, it is the same for everyone."
The Dutch, who are playing a warm-up tournament in Hong Kong with the United States, Cameroon and Ivory Coast, were given a stark warning of the potential problems they face.
De Haan ordered all the players to undergo a month of intense physical training, including spending time in humidity chambers that replicated the climate in Beijing, and two players, who had never had any previous problems with asthma, started to develop symptoms.
"We did a three-week programme with a lot of work on aerobic fitness," De Haan said. "We took all the players to a hospital in The Hague for tests and most of them were fine but two players started to show signs."
De Haan said the two unidentified players had reported their conditions to the International Olympic Committee in case they needed to take any medication during the Games.
Cameroon coach Martin Mpile said he had no major concerns about the pollution although he conceded the humidity could force some of the more athletic teams to curb their natural instincts to conserve their energy.
"That's why we have come here early, to adapt to the conditions," he said. "I don't know how the other teams will (cope) but we're going to try and play our own game.
U.S. coach Peter Nowak said he did not expect the conditions would make it any easier for his team to upset some of the top countries.
"There are no more miracles in soccer anymore," he said. "Anyone can beat anyone on any given day. The conditions are the same for everyone. It's not going to be easy, but we know that."