Impact of long term occupational exposure to ozone emitted from photocopiers on the respiratory system

ABSTRACT

The objective of this study was to determine the concentration of ozone in the indoor environment in photocopying centers and to investigate its possible respiratory effects among subjects engaged in the work in the photocopying process. Multiple air samples were collected from 4 photocopying centers and a control area containing no photocopying machines. Additionally, a questionnaire of respiratory symptoms was filled in [cough, phlegm, chest tightness and shortness of breath] and pulmonary function tests namely FVC% FEV1/FVC% and FEF25-75% were performed among 27 exposed subjects [15 females and 12 males] who were working in these photocopying centers and 29 matched control subjects [15 females and 14 males]. The measured ozone concentration exceeded the levels recommended by OSHA and NIOSH [200mg/m[3]] i.e 0. 1ppm in almost all air samples taken from the 4 photocopying centers. On the other hand, respiratory symptoms were statistically significantly more prevalent in the exposed group than in the controls. Similar results were obtained regarding the pulmonary function tests. On comparing the exposed subjects with >/= 5 years duration of work with those of < 5 years duration, there was a significant statistical difference [P<0.05] between the mean +/- SD of pulmonary function tests in both groups but no significant difference as regards the respiratory symptoms [P>0.05]. Comparison between the exposed females and males showed no statistical difference of significance. Correlation between the decline in pulmonary functions with duration of work and theTWA/8 hs of ozone was significant. Although, the ozone emitted from the photocopiers usually decays back to oxygen, it may exceed the recommended levels under certain conditions such as poor ventilation and bad maintenance. Long term occupational exposure to excessive amounts of ozone carries the risk of respiratory adverse effects with decline of pulmonary functions. Recommendations were stated to prevent the excessive ozone accumulation in the photocopying centers