Evaluation of AirPollution Control fromViewpoints of Cost- Benefit Analysis in a Tile Industry

Background and Aims:Methyl Methacrylate (MMA) which is known as a long, skin and eyeirritant is the most common form of acrylic plastic used in dental laboratories. The aims of thisstudy were to evaluate dental technicians, exposure to MMAand to assess their health with a focuson respiratory and dermal symptoms.Method: Exposure to MMA, total dust and health symptoms were investigated in 20 dentallaboratories located in Tehran, Iran. Time weighted average (TWA) of MMA and peakconcentrations were determined , using XAD-2 tubes followed by GC-ID analysis. Total dustwere evaluated gravimetrically. Health symptoms were asked using a questionnaire.Results :The TWAfor technicians with direct and indirect exposure to MMAwere 327.28 + 79.42and 282.9 + 41.84 mg/m3, respectively. Peak concentration of MMA for those technicians were337.0 + 36.81 and 328.88 + 45.40 mg/m3, respectively. There were no significant differencesbetween TWAof MMAand peak concentration in different weakly workdays; low ever, within -day variations were observed (P<0.05). TWAof MMA and peak concentration correlation withthe laboratory volume were 0.61- 0.65, Dust exposure of technicians was 2.35 + 2.70 mg/m3.Cough and Skin dryness were the common health symptoms. Smoking and asbestos exposurehistory were factors influencing cough prevalence (P<0.005).Conclusion:It is concluded that the current short - Term Exposure Limit (STEL) is not low enoughto protect technicians against the adverse effects caused by MMA