Matt Hill,
Environmental Science Department, University of Bradford, West Yorkshire BD7 1DP.
Tel: (01274) 235396
Fax: (01274) 234231
Email: mtrhill@bradford.ac.uk

I’m working as a research assistant on two projects. One is the development of a critical loads methodology for the atmospheric deposition of toxic metals to soils and surface waters in UK uplands, the other is the modelling of personal exposure of the UK population to air pollution. For parameterisation of the model in the latter project I have walked for standardised periods and velocities around rooms in six different houses in Bradford, West Yorkshire. While walking I have monitored counts/litre of particles inside the room and outside the building using GRIMM 1.108 and 1.105 portable dust monitors, and air exchange rates with SF₆ tracer gas and a Leybold Heraeus SF₆/N₂0 monitor borrowed from the Building Research Establishment.

I have used the results from this practical work to calculate air exchange rates for each sampling period and tried to discern any effect of walking around the rooms on those rates. Using the air exchange rates I have then calculated deposition velocities of the particle size fractions common to both GRIMM monitors (1-2mm, 2-5mm, 5-7.5mm, 7.5-10mm and 10-15mm), both taking into account outdoor concentrations and assuming zero outdoor concentrations. I have been assisted in these calculations by Sani Dimitroulopoulou of Imperial College, the project modeller.