PM10 Ireland overall average 2002-2005 red Traffic urban yellow Traffic suburban green Background suburban blue Industrial rural Overall PM10: 19 ug/m3 (median of means of sites) No east-west gradient apparent

Annual averages Trend between types Broad range within one type ug/m3 Range of means Median of means Traffic urban 19.2-28.4 (n=12) 21.3 Traffic suburban 14.3-32.4 (n=15) 19.0 Industrial rural 16.7-16.8 (n=2) 16.7 Background suburban 12.1-21.4 (n=15) 15.5

Dependence on wind direction Based on Dublin airport wind data Two Cork sites Two sites < 800 days Other sites > 1180 days Highest mean values for easterly wind directions This indicates a transboundary contribution to PM10 levels during easterly wind conditions This is consistent with Jennings et al.

Seasonal variation Similar levels in Cork and Dublin Seasonal maxima in Feb/March/April Contributing factors could include meteorology, traffic volume, home heating

Sea Salt in PM10, 2005 PM10 chemistry at three sites shows high seasalt contributions Carnsore started May 2005 SeaSalt is a major natural source in Ireland ug/m3 mean ± std median Max Malin Head 6.2 ± 5.5 4.9 29 Oak Park 1.8 ± 1.5 1.4 10.3 Carnsore Point 7.3 ± 6.2 5.5 38

Trans-boundary: nss SO4 PM10 episodes 2005 Elevated nss SO4 levels at three sites indicate regional rather than local source/event These events in combination with elevated PM10 could indicate transboundary contribution to PM10 levels

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