SOURCES OF ORGANIC-ACIDS IN INDOOR AIR - A FIELD-STUDY

Simultaneous indoor and outdoor measurements of organic acids were mad e at six residential houses located in a suburban New Jersey area duri ng the summer of 1992. Each house was measured for six days and contro lled for ventilation and gas combustion conditions. The study presents the first set of simultaneous measurements of formic and acetic acid in indoor and outdoor air. The concentrations of formic acid were 1.24 +/- 1.17 ppb outdoors and 8.77 +/- 4.67 ppb indoors. The concentratio ns of acetic acid were 3.05 +/- 3.63 ppb outdoors and 23.97 +/- 16.20 ppb indoors. The higher indoor concentrations indicated the presence o f significant indoor sources such as direct emissions and indoor chemi cal formation. However, the results indicated that organic acids indoo rs were not likely to be emitted from indoor gas combustion. The study also collected temperature, humidity, ozone, aldehyde, and nitrogen d ioxide data, and provided the supporting evidence for indoor chemical reaction pathways leading to organic acid formation.