The purpose of this study was to identify a suitable sampling model for on-site toxicity assessment of soluble air contaminants such as
formaldehyde, a well known industrial and indoor air contaminant. The in vitro cytotoxicity of
formaldehyde, the selected model for soluble air contaminants, was studied using the MTS (
tetrazolium salt) assay in two
carcinoma cell lines, A549 epithelial lung and HepG2 hepatocarcinoma, and in skin fibroblasts. The cytotoxic effects of airborne
formaldehyde were evaluated using test atmospheres in concentrations below 10 ppm (12.3 mg/m3), generated by a dynamic diffusion method and bubbled (0.3 L/min) through
serum-free culture media for one or four hours. Human cells were treated with
formaldehyde air samples, and cell viability was determined after four hours incubation. In parallel, the concentration of airborne
formaldehyde was monitored, using the 3500 NIOSH method. Cell viability of the HepG2 cells exposed to
formaldehyde air samples (8.75 ppm x 4 h) was reduced to less than 50% (31.6 +/- 1.24%). The HepG2 cell lines were found to be more sensitive (IC50 = 103.79 +/- 23.55 mg/L) to
formaldehyde than both A549 cell lines (IC50= 198.36 +/- 9.54 mg/L) and skin fibroblasts (IC50 = 196.68 +/- 36.73 mg/L) (P < 0.01). An average of 96.8% was determined for collection efficiency of
formaldehyde in
serum-free culture media. The results of this study suggest that absorption of soluble air contaminants, such as
formaldehyde, in
serum-free culture media can be used as a suitable sampling model for on-site toxicity assessments.