The soiling of materials in urban areas

This thesis considers the sources of airborne particulate matter and
dark smoke in the UK and its implication in the soiling of materials.
The role of particulate elemental carbon receives special consideration.
Results of emission inventories reveal that diesel emissions are
responsible for 60% of dark smoke in urban areas and 25% on a national
level. Particulate emissions have been identified as being largely
responsible for the soiling of building fabric in urban areas. It is
now being increasingly accepted that vehicle exhaust emissions make
major contributions to this fabric soiling as well as to the
deterioration of atmospheric quality within the urban environment.
Field work has been carried out at nine locations within metropolitan
London, where a variety of materials was displayed. The materials'
reflectance was measured at regular intervals together with pollution
and meteorological conditions for alperiod of eighteen months. Soiling
rates in the range of -0.02-4.5 yr were recorded. Particulate
samples were collected by a variety of methods and soiling rates were
measured in a traffic tunnel to assess the rate of sliling in the
absence of rainfall. Soiling rates of -0.5-0.8 yr were recorded.
Daily soiling rates for sheltered and exposed materials were measured in
a third field study.
A cost-benefit analysis of the building soiling problem was also
undertaken. The costings were achieved by a survey of UK stone
cleaning companies to identify their turnover, market characteristics,
mode and cleaning frequencies. The benefits were obtained by
interviewing typical clients of the stone cleaning companies to
ascertain the amount they spent per annum on stone cleaning and the
benefits accrued as a result of cleaning