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Spatial and temporal monitoring of temperature and relative humidity is essential for greenhouse management, therefore, wireless sensor networks (WSN) can offer crucial advantages. The objective of this work was to use a WSN to characterize and map the horizontal and vertical variability of air temperature and relative humidity inside a greenhouse using five different configurations. The configurations were based on combinations between the following actuating mechanisms: i) mechanical ventilation (by two exhaust fans); ii) natural ventilation (through the roof vent openings); iii) shading through the use of thermo-reflective screen. The WSN was designed with 45 spatially distributed measuring points, and the air temperature and relative humidity were recorded automatically every 30 seconds, for ten consecutive days, for each configuration. Our results show that the horizontal and vertical homogeneity of the meteorological elements depends on the actuating mechanism used in the greenhouse. Mechanical ventilation approximated the temperature and relative humidity of the indoor and outdoor air, with a homogeneous horizontal distribution throughout the environment. Opening the roof vent reduced vertical gradients of temperature and relative humidity. Our observations also showed that the combination of the use of roof vent openings with mechanical ventilation is an effective way to achieve horizontal homogeneity of meteorological elements.

Insulated windows (fixed triple glass window elements), became common in Finland during and after the energy crisis. Moisture tends to condense along the edges causing mold growth on the frames. Nine houses with insulated glass windows and eight with other types of window were studied. Fungus samples were taken from the window edges and from the inside air and cultivated on malt extract agar. In five of the houses with insulated windows there was visible mold growth on the window edges. The predominant fungus was Aureobasidium pullulans. With other types of windows there was only one case of visible mold. The eoncentrations of fungi were about the same in the air of houses with both types of windows. Aureobasidium was rare in the air samples. Thus, window frame molds seem to contribute very little to airborne fungus concentrations. In situ trials were done to control the mold growth with disinfectants. Repeated spraying with aldehydes or quaternary ammonium chlorides in alcohols proved to be successful. [ABSTRACT FROM AUTHOR]