An industrial hygienist releases resorcinol gas (MW 110.1) into a 20 ft X 15 ft x 9 ft room (mixing factor 1.5) at a rate of 0.10 cubic feet per minute(cfm). The room ventilation rate is 15,000 cfm. He waits until the room reaches steady-state conditions. He then collects an active sample, a passive sample and a direct reading from an instrument. The active sample was collected at a sample rate of 100 milliliters per minute for 2 hours. The analysis of the sample indicated that 0.486 mg were collected. The passive sample was exposed for 456 minutes. The final reading from the passive sampler was 79.8 ppm-hr. The instrument reads 42.78 mg/m3. What is the % error for each of the measurements?

Room concentration

Active sample concentration

Passive sampler concentration

Error calculations