Environmental Engineering Reference
In-Depth Information
concentrations (PNC) are dominated by UFPs
[2, 13]
suggesting that this metric
could be more indicative of potential health impacts of particles. Because of this
reason many researchers have paid increasing attention to UFP in the atmosphere,
especially close to road traffic which contributes significantly to particle number
concentrations
[9, 13, 14]
.
Exposure of drivers and passengers in vehicles and in restricted environments
(e.g. tunnels and canyons) is of particular concern because of elevated levels of
particle concentrations in these situations compared to elsewhere
[15, 16]
.
This study thus aimed to investigate the exposure of drivers and passengers
travelling through a tunnel on a busy urban motorway in Leeds, UK. This study also
aimed to investigate if the particle levels were higher inside the tunnel than the
outside. Spatial and temporal variations in PNCs in the tunnel and car cabin
were determined to quantify personal exposures. This study also helped to test if
mobile measurements can be used to investigate temporal and spatial exposure to
ultrafine particles. Currently, there are no limit or guideline values for particles.
This study could help in understanding personal exposure of commuters and thus
help in developing legal standards for UFPs.
Experimental Method
Study Area
: The Westgate tunnel (Fig.
1
) in Leeds, UK is one of the longest unven-
tilated tunnels in Europe, and relies solely on natural ventilation generated by wind
movements and the piston effect of moving vehicles forcing the movement of air.
The eastbound bore is 392 m in length and the westbound bore slightly shorter at
380 m due to the curvature of the tunnel's alignment (Fig.
2
); however both bores
Fig. 1
Westgate tunnel,
Leeds, UK
