This has been estimated on the basis of the floor area of construction. A US study (USEPA, 1995) has produced an estimate of 2.69 tonnes/hectare/month for the total particulate emissions from the construction of a shopping centre. Assuming that this is 20% PM10 this gives an emission factor of 0.538 tonnes/hectare/month. (20% is the fraction of PM10 in road dust - the best available data). However, the UK climate is much damper than that of the US and so the US data is not truly appropriate for the UK. Nevertheless, it can be used to provide a first estimate. In the UK the number of days with rain is about 150 to 250 (as measured by the DOE’s acid rain monitoring network ( Hjellbrekke et al., 1995)). Thus the emissions should be less than one half of that expected in an arid climate.
In the UK, annual construction currently amounts to 150,000 to 200,000 houses; 2 to 2.5 million m2 of office space; 11.5 to 12.5 million m2 of industrial and warehousing space and 1.5 to 2 million m2 of retail floor space (DOE 1992, 1994).
Assumptions about the typical industrial and commercial floor space and construction times leads to UK estimates of 0.5 - 8.3 kt PM10 per year.
This can be compared with estimates based on the construction waste produced per year. This amounts to about 70 million tonnes per year of which about 24 million tonnes are brick and concrete and most of the remainder soil and clay (DOE, 1995). Emissions of 0.5 - 8.3 kt would indicated emission factors of 0.007 to 0.119 kg/tonne of waste produced. This compares well with factors for mining and quarrying that range from 0.001 to 54 kg/tonne (USEPA, 1995) especially considering the effect of the UK climate.
A mid range estimate of 4 kt/year was adopted. No attempt was made to give a time series for this sources due to its inherent uncertainties.