Air quality standards for particles US 15 ug/m3(annual average)for PM 2. 5 um 65 ug/m3(daily average)for PM 2. 5 um Hong Kong RSP: 55 ug/m3(annual),180 ug/m3(daily) TSP: 80 ug/m3(annuaL),260 ug/m3(daily)Air quality standards for particles • US – 15 ug/m3 (annual average) for PM 2.5 um – 65 ug/m3 (daily average) for PM 2.5 um • Hong Kong – RSP: 55 ug/m3 (annual), 180 ug/m3 (daily) – TSP: 80 ug/m3 (annual), 260 ug/m3 (daily)