The impact of wind on particle mass concentrations in four european urban areas

The impacts of wind conditions to fine and coarse particle mass concentrations at four European urban centers, by multivariate regression analysis of particle measurements against categorized wind (direction and speed) conditions were estimated. Statistically significant associations (both positive and negative) were observed for all urban areas. Both fine and coarse particle mass concentrations were decreased for moderate and strong winds (speed > 2.2 m s-1) in Athens and Helsinki. Weak winds had a positive influence on particle mass, accounting for up to 40% of fine particles in Athens. For the three coastal urban areas (Amsterdam, Athens and Helsinki), positive correlations were observed for sectors encompassing ports and areas with intense marine traffic. For Birmingham, the association of both particle fractions with the eastern sector indicated the influence of emissions from central UK and continental Europe. The method described here may be used to screen the orientation of sources near receptor sites.