where DAD is dermal absorbed dose, mg kg_1 day_1; DAevent is absorbed dose per event, mg cm_2 event_1; EV is event frequency, 2 events day_1; SA is skin surface area available for contact, 2733 cm2; BW is body weight, 70 kg; C is contaminant concentration in fly ash, mg kg_1; CF is conversion factor, 10_6 kg mg_1; AF is adherence factor of particle to skin, 0.7 mg cm_2 event_1; ABSd is dermal absorption fraction, 0.14; HQder (unitless) is hazard quotient; RfDd is chronic dermal reference dose, 3.0 _ 10_4 mg kg_1 day_1. EF, ED, AT were the same to those in Eq. (1).