Sacramento Bee article on NYC air hazards, Oct 2001

NYC 9/11 Public Portal Document

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However, there are few established safety guidelines for airborne metals. One metal for which there is a guideline, lead, was present at low levels in fine and very fine partides.

Some of the metals for which there are no guidelines that were present In very fine partides in relatively high concentrations were Iron, titanium (some associated with powdered concrete), vanadium and nickel (often assodated with fuel-oil combustion), copper and zinc. Mercury was seen occasionally in fine partides but at low concentrations. Many of those metals are widely used In building construction, wiring and plumbing. Some are common in computers.

The metal content of the coarse particles is still being analyzed.

Asbestos and glass

Although some asbestos was used in foe buildings for fireproofing and in floor tiles, and the DELTA group checked for it carefully using foe electron microscope, they found very few asbestos fibers, even in foe very fine partides.

Some partides that appeared to be glass were seen, but they were not In the form of long shards, which can mimic asbestos fibers.

Clean-up recommendations

All evidence indicates that ambient air In New York City now is little Influenced by foe World Trade Center cdtapse, especially since foe fires are out and the debris pile has cooled.

However, the presence of large amounts of very tine particles as late as October means that indoor dean up should be done carefully, Cahill said. Very fine partides will have penetrated crevices and fabrics in a way normal dust doesn't And they are easily re-suspended, which re-exposes the room's occupants to them.

Cahill strongly supports foe recommendations made by foe New York Department of Health regarding washing with water, and said:

- Dont use vacuum deaners or brooms because they re -suspend partides. Do use wet regs, mops and wet- vacuum-type deaners.

- Wipe all surfaces, including window blinds, picture tops and door frames, with wet rags.

- Drapes and curtains should be washed or dry-deaned. Furniture fabrics should be steam-deaned. Carpets should be wet-deaned.

- Use high efficiency electrostatic or HEPA air filters in furnaces and air conditioners.

- Keep humidity reasonably high Indoors, to keep very fine particles from floating around.

UCOavto DELTA Group

The UC Davis DELTA Group Is one of foe world's leading research groups in analyzing foe size, composition and movement of airborne partides. DELTA Group sdentists analyzing foe trade center samples induded Cahill; engineering professor James Shackelford, Ph.D., who led foe scanning electron microscopy; diemistry professor Peter Kelly, Ph.D. who led foe mass spectroscopy; assistant research engineer Steve Cliff, Ph.D., who is project manager for foe synchrotron program, and laboratory and field manager Michael Jimenez-Cruz, toxicologist

Key collaborators from other institutions were Kevin Perry, Ph.D., a former Cahill postdoctoral cdlaborator and now an assistant professor of meteorology at the University of Utah, Salt Lake City; Graham Bench, Ph.D., a project investigator at foe Center for Accelerator Mass Spectroscopy, U.S. Department of Energy's Lawrence Livermore National Laboratory, and his team of sdentists; and Jodye Selco, Ph.D., a visiting professor at UC Davis and a professor of chemistry at foe University of Redlands, Redlands, California.

The DELTA Group's many previous research prefects indude studies of foe smoke from the Kuwaiti oil fires and two International ACE studies (for Aerosol Characterization Experiment), which are designed to shed light on foe roles of aerosols in global weather, water pollution and human disease. The most recent, ACE- Asia, operated under National Sdence Foundation funding with 21 aerosol-sampling sites from Asia to

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