Ct 13
Ct 13 : This means concentration times time. Note that Ct ??k, a 2-minute exposure to a concentration of 100 mg/m3 (Ct = 200 milligram-minutes per cubic meter (mg-min/m3)), does NOT necessarily produce the same toxicological effects as a 50-minute exposure to a concentration of 4 mg/m3 (Ct = 200 mg-min/m3)