To protect the health of clean-up workers at the wreckage of the World Trade Center, UC Davis will collect and analyze air samples from the site using state-of-the-art technology it has developed.

The U.S. Environmental Protection Agency asked the Department of Energy for monitoring help, said Tom Cahill, UC Davis professor of applied science and atmospheric sciences. Robert Leifer, a senior research scientist at the DOE Environmental Measurements Laboratory in New York, called the UC Davis DELTA Group (for Detection and Evaluation of Long-Range Transport of Aerosols), to collaborate on sampling near the Trade Center site.

DELTA Group is a world leader in analyzing the composition and movement of airborne particles.

"DOE called UC Davis because our ability to measure particle size, composition and time continuously, day and night, is unequaled," Cahill said. "In three hours, we had a sampler on the way to New York City."

In the next several months, workers at the scene will move roughly 1.2 million tons of debris, the New York Times has reported. That includes steel reinforcing, concrete floor slabs, aluminum, glass, various ceiling and flooring materials, wood and drywall.

On the roof of a building downwind from ground zero, a Davis Rotating Unit for Monitoring (DRUM) is collecting air samples continuously in eight size ranges, some of which represent very fine dust that goes deep into the lungs. Sampling began on Oct. 1, Cahill said, and will continue as long as needed.

The first batch of samples will be shipped to UC Davis for analysis on Nov. 5. Scientists will look for health threats such as inhalable particles, toxic metals, asbestos and byproducts of burning plastic. The analyses will be conducted by UC Davis assistant research engineer Steve Cliff, chemistry professor Pete Kelly, engineering professor Jim Shackelford and, from Lawrence Livermore National Laboratory, project investigator Graham Bench.

Cahill said details about the composition of airborne particles should help clean-up authorities decide on safety measures at the site, such as what equipment workers should wear (face masks, respirators, specific filters, body suits) and how long work shifts should last.