Cab filtration systems can be used to protect vehicle operators
from hazardous air contaminants. In a cab filtration system, a
fan draws air through filters and pressurizes the cab with this
filtered air. This article describes the application of a low-
cost, optical particle counter to evaluate the performance of
tractor cab filtration systems. The tractors were equipped with
environmental enclosures to protect the operators from pesticide
exposures that occur during air blast spraying in orchards.
Prior to testing, all environmental tractor cabs underwent a
complete maintenance overhaul followed by a careful inspection
by the manufacturer's field representative. As part of this
maintenance effort, 13 tractors with cab filtration systems were
tested in an enclosure. A Met One model 227B two-channel optical
particle counter was used to measure the aerosol concentration
outside and inside the cab. Ambient aerosol and/or aerosol
generated by burning incense sticks were used to challenge the
stationary cab filtra