Sampling and analytical procedures are described that were successfully used to monitor for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in air samples collected near a superfund site clean-up operation. Measured concentrations of 2,3,7,8-TCDD in air samples are related to an action level of 3.0 picograms/cubic meter of air (pg/m³) and to a calculated no observed effect level of 5.5 pg/m³. The study concluded that it is possible to collect reliable data for 2,3,7,8-TCDD in air at concentrations that are below the action level specified by the Centers for Disease Control. Data quality was defined relative to the quality control procedures described in the study. There was no apparent relationship between particulate matter in the air and 2,3,7,8-TCDD in the air.