Ellis has recently performed a number of preliminary air quality assessments in office buildings in and around Los Angeles and other airports. The sampling is often prompted by office occupants’ observations of settled carbon black dust on shelves, desks and ventilation grilles.
As a matter of standard practice in such efforts, Ellis will include sampling for various types of dusts: PM10, nuisance, respirable, fibrous (including asbestos and fiberglass) . . . . and something relatively new in the industry; “ultra-fine particles,” or “UFPs.”
UFPs are those particles measuring less than 0.1 micron in diameter. In any given sample of air, UFPs constitute the greatest number of particles, yet make up only a small fraction of the mass. Although researchers are currently studying UFPs to identify any links to specific health effects, actual IAQ investigations in thousands of buildings have already shown that UFPs can be directly related to complaints. Due to their numerous quantity and ability to penetrate deep within the lung, UFPs are a major concern for respiratory exposure and health. This is of special concern in airport areas. Why? Read on . . .
UFPs are usually products of combustion or chemical reactions.
They can come from a wide variety of sources. In airport areas, diesel jet turbine exhaust can be a significant source of UFPs. Ultra-fine or nanoparticles are not detectable with conventional respirable or PM-10 monitoring equipment. Instead, sampling for ultra-fine dust particles is performed using a TSI Model 3007 condensation particle counter. Owned, operated and maintained by Ellis, this is a hand-held CPC intended for measuring ultra-fine particles in a wide variety of applications. Highly portable, the machine provides immediate results in the field.
Recent studies in airport areas indicate that airborne levels of UFPs can rise and fall dramatically with each landing and takeoff event. UFPs are extremely susceptible to wind currents, varying from less than 5,000 particles per cubic meter (p/m3) upwind, to more than 30,000 p/m3 downwind.
The good news? We’ve also found that a building’s ventilation system - in good working order and with filters changed regularly - is effective in keeping UFP concentrations at or near normal upwind levels.