A CHEMICAL AND TOXICOLOGICAL COMPARISON OF URBAN AIR PM10 COLLECTED DURING WINTER AND SPRING IN FINLAND

We have used a new high-volume, low-cutoff inertial impactor (HVLI) in a pilot study on chemical characterization and toxicity testing of ambient air PM10 in Helsinki, Finland. Ambient air PM 10 was collected at 1100 L/min in 2- to 4-day periods. Two different PM 10 samples were selected to represent wintertime combustion type and springtime resuspension type particulate matter (PM) pollution. The most abundant water-soluble ions and elements were analyzed by ion chromatography and inductively coupled plasma mass spectrometry, respectively. The proinflammatory activation [NO and interleukin 6 (IL-6) production] and viability of cultured murine RAW 264.7 macrophages were tested in 24-h incubations with increasing mass doses (30-2000 µg per 10 6 cells) from the collected PM 10 samples. The winter sample had a higher assessed PM 2.5 fraction and sulfate content, and lower chloride, sodium, calcium, aluminum, copper, manganese, and especially iron contents than the spring sample. Both PM 10 samples induced dose-dependent NO production in murine macrophages, and the springtime PM 10 produced also a strong, dose-dependent IL-6 production. In conclusion, the HVLI proved to be a suitable technique for short-term collection of relatively large ambient air PM masses, enabling extensive chemical characterization and toxicity testing from the same samples.