PM10 levels at urban, suburban, and background locations in the eastern Mediterranean: local versus regional sources with emphasis on African dust

PM10 levels were determined at different locations in a coastal site in the eastern Mediterranean to assess the relative contribution of local versus regional sources. Two campaigns were conducted: during the first, PM10 was monitored at three urban locations (kerbside/traffic/background) at different sampling periods, whereas during the second one, PM10 was simultaneously measured at two locations (urban/suburban). Both campaigns have shown that African dust transport was a major carrier of coarse particles. Daily PM10 concentrations of 547 mu g m(-3) and 234 mu g m(-3) were measured during the first and the second campaigns, respectively, both of them associated with severe dust storms. However, some dust episodes influenced lesser PM10 levels. The contribution from dust episodes to the measured concentration was estimated at 2-527 mu g m(-3) during the first campaign and 4-218 mu g m(-3) during the second campaign. Classification into dusty and non-dusty days has shown that local anthropogenic sources also influence ambient PM10 concentrations; however, few exceedances of the daily limit of 50 mu g m(-3) occurred during both campaigns. Particularly, it was found that domestic heating during cold months was a major contributor to PM10 levels followed by emissions from traffic with higher contribution of the latter during summer months (high touristic season) as well as non-traffic emissions (road dust resuspension). Hourly average PM10 concentration during the second campaign has shown that traffic-related emissions and/or road dust resuspension were associated with up to 40 mu g m(-3) whereas during wintertime late evening hours, PM10 concentration from heating reached up to 60 mu g m(-3) at the central urban location.