Deposition Rates of Fine and Coarse Particles in Residential Buildings: Literature Review and Measurements in an Occupied Townhouse.
Deposition Rates of Fine and Coarse Particles in
Residential Buildings: Literature Review and
Measurements in an Occupied Townhouse.
Howard-Reed, C.; Wallace, L.; Emmerich, S. J.
NISTIR 7068; 29 p. October 2003.
Available from:Orders Only) 800-553-6847;
residential buildings; fine particles; coarse particles;
deposition; filtration; residential indoor air quality
Several studies have shown the importance of particle
losses in real homes due to deposition and filtration;
however, none have quantitatively shown the impact of
using a central forced air fan and in-duct filter on
particle loss rates. In an attempt to provide such data,
we measured the deposition of fine and coarse particles
following specific source events in an occupied
townhouse and also in an unoccupied test house.
Experiments were run with three different sources (gas
stove, citronella candle, pouring kitty litter), with
the central heating and air conditioning (HAC) fan on or
off, and with two different types of in-duct filters
(electrostatic precipitator and ordinary furnace
filter). These tests resulted in a database of
deposition rates for particles ranging from 0.3 m to 10
m under a wide range of occupancy conditions. Particle
size, HAC fan operation, and the electrostatic
precipitator had significant effects on particle loss
rates. The standard furnace filter had no effect on loss
rates. Surprisingly, the type of source (combustion vs.
mechanical generation) and the type of furnishings
(fully furnished including carpet vs. largely
unfurnished including mostly bare floor) also had no
measurable effect on the deposition rates of particles
of comparable size. With the HAC fan off, average
deposition rates varied from 0.3 h-1 for the smallest
particle range (0.3 m to 0.5 m) to 5.2 h-1 for particles
greater than 10 m. Operation of the central HAC fan
approximately doubled these rates for particles < 5 m,
and increased rates by 2 h-1 for the larger particles.
An in-duct electrostatic precipitator increased the loss
rates compared to the fan-off condition by factors of 5
to 10 for particles < 2.5 m, and by a factor of 3 for
the larger particles.