Environmental Engineering Reference
In-Depth Information
Air Pollution Exposure in an Unventilated
Tunnel in Leeds, UK
Anil Namdeo and James Tippins
Introduction
Traffic emission is known as the major source of air pollution in urban areas,
which contribute substantially to ambient levels of particulate matter and a range
of gaseous pollutants. The continual traffic growth has raised concerns over the
impact of traffic emissions on human health and urban environmental quality.
Roadside concentrations of ultra-fine particles, NO and other pollutants can be up
to 20 magnitudes greater than at residential locations. Such spatial variations are a
factor of traffic volume, driver behavior, fleet composition, meteorological and the
surrounding built environment. Canyons and tunnels, along with other road features
are known potential pollution hotspots
[1-4]
. In canyons and tunnels, exposures to
pollutants are often elevated in comparison to elsewhere so that individuals may
gain a significant contribution to daily total exposure
[2]
.
Particles have been documented to increase mortality, morbidity and decreased
lung function
[5]
. Industry and vehicular traffic are major anthropogenic sources
of particles. Most of the studies have linked health effects to mass concentration of
particles under 10 µm (PM
10
) in size. However, there is considerable uncertainty
about which physical and/or chemical characteristics of PM are most important of
determinants of health effects. Recent studies have shown that ultrafine particles
(with d < 0.1 mm) are more toxic than larger particles
[6, 7]
. Ultra fine particles
(UFP) are important because of their larger surface area and the ability to deposit
in high alveolar region and the ability to induce inflammation
[8-12]
. Particle number
A. Namdeo
Institute for Transport Studies, University of Leeds, Leeds, LS2 9JT, UK
Transport Operations Research Group, Newcastle University,
Newcastle upon Tyne NE1 7RU, UK
J. Tippins
JMP Consulting, Blackfriars House, Parsonage, Manchester, M3 2JA, UK
