Air Quality Assessment – Construction
Demolition, remediation, site preparation and construction are phases that are easily overlooked during a development programme, as they generally represent a fraction of a scheme’s lifecycle. However, if the potential effects on air quality of these phases are not effectively assessed and mitigated, then they can cause highly significant local effects. For the majority of construction projects, emissions of dust are the greatest concern in terms of air quality impacts.
Emissions of toxic gasses, vapours and fine particulate matter can also be significant, particularly on contaminated, brownfield sites. Consideration of construction phase effects is also a requirement of the Environmental Impact Assessment Regulations. It is therefore often necessary to assess, model, predict and/or monitor emissions to the atmosphere during the phases of a development project before it is occupied and becomes operational. In addition to the models and assessment tools used for industrial and vehicular emissions, Phlorum Limited has the capability to provide these additional air quality assessment services for a wide range of development projects.
Guidance published by the Institute of Air Quality Management separates emissions from construction activities into a number of distinct source groups or phases, which include: demolition of existing structures; ground clearance and earthworks; construction of new structures; and movements of vehicles and plant along access routes and soiled road surfaces. There is also specific guidance for minerals works, which often use similar plant carrying out similar tasks to those associated with large construction earthworks.
Dust impacts on vegetation and ecologically sensitive areas also need to be considered. However, the lower sensitivity of such habitat usually makes it more resistant to the much lower concentrations and rates of deposited dusts that can potentially cause health impacts in humans or cause nuisance effects.
The most common monitoring and assessment methods we use at Phlorum include the following:
- Monitoring of dust deposition rates and analysis of deposited dusts (e.g. morphological source apportionment analyses using scanning electron microscopy, x-ray microprobe analysis and spectrophotometry);
- Realtime sampling of airborne fine particulate matter (e.g. in the PM10, PM2.5 and PM1 size fractions);
- Pumped and passive sampling of speciated volatile organic compounds using sorbent media (e.g. Tenax and Sulphicarb tubes); and
- Odour sampling and analysis (e.g. methodological ‘sniff-testing’ and collection of air samples for olfactometric analysis).