Effects of soil dust episodes and mixed fuel sources on source apportionment of PM10 particles in Kuopio, Finland

A receptor modeling study was carried out in Kuopio, Finland, between Janua ry and April 1994. Near the center of town, the daily mean concentrations w ere measured for PM10, sulphur dioxide, carbon monoxide and Black Smoke. El emental concentrations of PM10 samples for 38 days were analyzed by ICP-MS. The main sources and their contributions to the measured concentrations of PM10 particles were solved by receptor modeling using a factor analysis-mu ltiple linear regression (FA-MLR) model. Because a dust episode was very st rong during two sampling days, the FA analysis was strongly influenced by t his episode and did not give main factors. The factor analysis, when the tw o episode days were omitted, gave credible factors related to the sources i n the study area. The four major sources and their estimated contributions to the average PM10 concentration of 27.2 mu g m(-3) were: soil and street dust 46-48%, heavy fuel oil burning 12-18%, traffic exhaust 10-14%, wood bu rning ca. 11% and unidentified sources 15-25%. However, during spring dust episode days, with maximum PM10 concentration of 150 mu g m(-3), the main s ource of PM10 was soil. (C) 1999 Elsevier Science Ltd. All rights reserved.