METHODS
We collected data on short term average noise
levels (equivalent continuous sound level over
5 min, Leq,5min) for 103 roadside sites in the
Metro Vancouver region of British Columbia. At
the same locations, data on 2-week concentration
averages for nitrogen dioxide (NO2) and nitrogen
oxides (NOX) were collected, as described elsewhere.11
The noise samples were collected at the
start of the air pollution sampling period during
daytime hours (08:00–18:00). Sampling sites were
selected using a location-allocation model that
included land use, road networks, population
density and regulatory air-quality monitoring to
optimally place sampling locations with respect to
air pollutants.
12
NO2 and NOX 14-day averages
were collected with passive samplers equipped
with a pre-coated pollutant collection pad
(Ogawa USA, Pompano Beach, Florida), and
analysis was by liquid chromatography. NO2/
NOX samplers were positioned approximately
3 m from the ground. Noise levels were measured
with an LDL 870 Environmental Noise Analyser
(Larson Davis, Provo, Utah) and an LDL 2559
microphone, positioned 1.2 m from the ground at a
90u angle to the roadway. Calibration was