We have sampled PM10 for 3 hours duration daily in fixed time slots, i.e. 8 filter papers were used for 24 papers. At end of 3 hours sampling, filter papers were stored and were again used for the next 7 days for 3 hours in respective time slots respectively. Finally we got 8 filter papers each having 24 hr sampling (3 hr daily in a particular time slot for 8 days). All filter papers were analysed for metals and PAHs. We are unable to find reference of any such study. I will be grateful if someone can suggest the reference of any similar study.