Road construction: Emissions Factors and Air Quality Impacts

Downwind-upwind differences were used to calculate real-world PM10 emissions associated to the construction activity by means of box modelling. The quantity of PM10 emitted per area and month of construction was 0.0009 kg PM10 m-2 month-1 for the construction period. This emission factor was similar to the one used in the UK National Atmospheric Emissions Inventory (NAEI). Worst case construction emissions factors were 0.0105 kg PM10 m-2 month-1, compared to 0.0448 kg PM10 m-2 month-1 and 0.1038 kg PM10 m-2 month-1 used in current European and US inventories, respectively. After the completion of the road widening an increase in all pollutants was measured during rush hour peaks: 2-4 g m-3 for PM10; 1 g m-3 for PM2.5; 20 and 4 ppbv (40 and 8 g m-3) for NOX and NO2, respectively, leading to a breach of the NO2 annual mean LV at this location for the first time. The increased air pollution was associated with an increase in the number of cars, taxis and LGVs. The glutathione dependent oxidative potential did not increase during the construction period but a significant increase was found when the new widened road was in operation.