Environmental Engineering Reference
In-Depth Information
Fig. 2
Sampling route (© Crown Copyright/database right 2007. An Ordnance Survey/EDINA
supplied service)
are greater than the advised maximum 240 m in length for unventilated tunnels
[ASHRAE 1999 cited in
17]
. The tunnel is also on a slight gradient with the
westbound traffic flowing downhill. The tunnel forms part of the Leeds Inner
Ring Road, and was constructed within a vertical cutting to limit its intrusion into
the surrounding environment.
Monitoring Setup
: TSI Model 3007 Condensation Particle Counter (CPC) was
chosen in this study for ultrafine particle measurements. This model has success-
fully been used in a previous study to measure UFPs on a mobile vehicle platform
[18]
. This is a portable unit and is capable of detecting particles in the range of 10
nm to >1 mm
[19]
.
Prior to each session the alcohol cartridge was replaced, and the CPC allowed to
complete a full 600-s warm up, before carrying out a 15 s zero test using the factory
supplied zero filter. The internal clock was updated to GPS time, which was available
from car's CAN (Computer Aided Network) tablet interface. The logging interval
for all sampling was set to one second to ensure the highest resolution of data was
available for analysis. A 2003 Ford Mondeo hatchback (2.0 TDCi LX) was used as the
platform for the monitoring equipment. The car was fitted with a data acquisition
PC with wireless tablet interface, which logged data from the onboard Differential
GPS receiver and CAN at 10 Hz.
Two sampling locations were chosen to monitor PNCs; the roof rack of the
car for external and the back of the driver's headrest for internal measurements.
Two sampling lines were used to connect to two CPCs which were located in the
