Jd. Pleil et al., SPATIALLY RESOLVED MONITORING FOR VOLATILE ORGANIC-COMPOUNDS USING REMOTE SECTOR SAMPLING, Atmospheric environment. Part B, Urban atmosphere, 27(5), 1993, pp. 739-747
Sector sampling for volatile organic compounds (VOCs) is conducted wit
hin an integrated sampling scheme and relies on a wind direction senso
r. The wind sensor directs whole air, sampled at a constant rate, into
either an ''IN'' sector canister or an ''OUT'' sector canister; when
the wind comes from the suspected emissions area, sample is routed int
o the IN sector canister, otherwise, sample is collected in the OUT se
ctor canister. This method is analogous to ''upwind/downwind'' samplin
g but does not require two distinct sites or manual sampler control. F
or this set of experiments, the IN and OUT sectors were 90 and 270-deg
rees, respectively, and the IN sector was centered on the VOC source.
Two sampling sites were used. The first was about 2 miles north-northe
ast of a group of industrial facilities, and the second was located ab
out 1 mile south-southeast of the same sources. Sites were operated co
ncurrently with one sampler each; a third sampler was rotated between
the sites to obtain duplicate samples. The air samples were analysed b
y gas chromatography for VOCs. The resultant data comparisons between
IN and OUT duplicate samples show good correlation with expected VOC e
missions, which were determined by grab samples within the target area
. A t-test method for interpreting the sometimes subtle differences be
tween IN and OUT sample data is presented.