Objective To examine indoor ambient in solar greenhouses (SGH) in Shandong and related impacts on the health of greenhouse workers.
Methods This study interviewed 1 171 farmers engaged in SGH work from 5 main vegetable production regions in Shandong province and 850 farmers without SGH vegetable production as controls (matched by age and gender) using questionnaires. Three greenhouses in Shouguang city were chosen randomly to detect the indoor temperature and relative humidity, as well as concentrations of NH3, Cl2, and PM10.
Results Seventy-four subjects in the exposed group had past medical history. The positive rates of self-reported symptoms of the exposed and control groups were 59.3% (650/1 097) and 28.7% (244/850). The prevalence of bone and joint pain was elevated with greenhouse working years and day work time. There was a significant difference in positive rates of selected symptoms among SGH workers using various fertilizer application procedures (χ2=29.09, P<0.05). For the selected greenhouses in Shouguang city, the indoor and outdoor temperature difference was (12.8& #177;4.09)℃; the average indoor temperature was (24.2& #177;9.73℃); the average relative humidity was (79.2& #177;18.87)%; the indoor concentrations of NH3, Cl2, and PM10 were (0.61& #177;0.42)mg/m3, (1.61& #177;0.49)mg/m3, and (0.16& #177;0.03)mg/m3, respectively, and the corresponding unqualified rates were 84%, 100%, and 81%, respectively.
Conclusion Relative high temperature and humidity are found in the indoor ambient of the SGHs investigated. Moreover, the indoor concentrations of NH3, Cl2, and PM10 are higher than relevant national standards. Therefore, the negative long-term health impact of SGH ambient among greenhouse workers should be of concern.
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