Measurement campaign was conducted in a controlled office environment during January 1999 to get indoor/outdoor ratio for particles less than 0.5 micrometers in diameter. Aerosol concentrations for diameters between 7-500 nanometers were measured simultaneously indoors and outdoors with two DMPS systems. Other continuously measured quantities included temperature, ventilation rate, relative humidity, air pressure and four inorganic gases (S02, NO, NOx and 03). The measured room was practically airtight and had a mechanical ventilation system.
During the experiments and under the experimental conditions, displacement ventilation with air outlets close to floor level were found to produce the lowest concentrations of hazardous substances and aerosols in the working areas of kitchen appliances when compared with mixed or displacement ventilation through ceiling outlets. Displacement ventilation with low-induction ceiling outlets achieved better results than mixed ventilation.
Application of industrial painting is often carried out by air-atomization. In this case, health hazards arise from the exposure to solid and liquid aerosols as well as to solvent vapors. Control of these airborne pollutants may be achieved through the use of a spray booth, whose effectiveness depends also on the number and dimension of the openings, on the main air flow rate, as well as on the direction and flow rate of secondary air streams.
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