PORTLAND (AP) — A Grants Pass company is helping the U.S. Embassy monitor air quality at the Beijing Olympics.

Managers at Met One Instruments Inc. shipped three hand-held air monitors to China last month. Earlier, the embassy bought a stationary monitor to track particulates.

An embassy spokeswoman declined to comment on the purchases. But a top U.S. air-quality expert said it’s important to verify the data circulated by Chinese authorities.

“I would not be suspicious of the actual data the Chinese collect,” said physicist Tom Cahill, a University of California at Davis emeritus professor of atmospheric sciences. “I’d be very suspicious of their interpretation of it.”

China’s air quality has been a hot topic in the months leading up to the games that start this week. In an attempt to reduce pollution, Chinese authorities closed scores of factories and pulled some 2 million vehicles off the roads in northern China. Cahill, however, said air quality likely will depend more on wind direction than those efforts to cut pollution.

Met One’s Aerocet-531 mass particle counters and dust monitors are portable battery-operated units that quickly measure particle counts and sizes.

Peter Pomponi, Met One’s vice president of sales, would not say how much the embassy paid for the monitors, but said the devices can detect particles small enough to lodge in people’s lungs.

“From what I was told,” Pomponi said, “they would have personnel taking readings at different locations in the city to get an idea of what the exposure levels would be to U.S. personnel, athletes and tourists visiting the games.”