air quality

Indoor air quality in an air conditioned California high school has been measured over a variety of ventilation rates ranging from 13.3 cubic feet of outside air per minute for each classroom occupant to approximately 1.5 cfm per occupant.< Parameters measured include outside air supply rate, the occupants' subjective perception of indoor air quality, airborne microbes, carbon dioxide, carbon monoxide, nitrogen oxide, sulphur dioxide and ozone in two classrooms, a halland outdoors.

Working men's clubs are commercially thriving organisations catering for a wide range of social activities commonly held in a single room holding 300-400 people. Packaged air conditioning is being introduced into Working Men's Clubs to provide air recirculation and cleaning when the buildings are occupied. Air cooling and dehumidification is also available. One club was dissatisfied and an investigation was started to investigate the difference. Measurements showed that the unsatisfactory installation was unusual in two ways.

Discusses indoor air quality in residences with low ventilation rates. Reports investigation of indoor air pollutant levels in a test kitchen with a gas stove under various air change rates. Results indicate that gas stoves generate high emissions of carbon monoxide, nitric oxide, nitrogen dioxide, formaldehyde and respirable aerosols. Recommends a kitchen ventilation rate of at least 170 cu.m.&h.< Also reports study of CO and NO2 emissions from gas appliances in an energy- efficient research house.

Ventilation measurements in new Swedish houses show that they seldom fulfill minimum requirements of 0.5 air changes per. hour applicable to specific housing classifications. Basic natural ventilation is often used. Discusses consequent problems including condensation and humidity, excess radon daughters and formaldehyde content in the room air. Notes future demands for systems to include heat exchangers.

In some buildings in Canada ventilation systems are being operated with the outside air supply dampers completely closed during winter to reduce ventilation and hence conserve energy. Reports measurements of the carbon dioxide concentrations in the classrooms of a small elementary school, when the outside air-supply damper was closed, to assess whether ventilation was adequate. Concentrations were found to be well below the maximum accepted occupational standard of 0.5% and air infiltration gave an adequate fresh air supply.

Reviews the source and nature of pollutants occurring in indoor air. Discusses two research projects at the Institute of Hygiene and Work Physiology of the Swiss Federal Institute of Technology in Zurich; one studying the air pollution caused by men; theother concentrates on pollution caused by materials. Outlines methods of investigating odours. Concludes that control measures to reduce emissions are necessary. Recommends that guidelines for a minimum ventilation rate should be drawn.

Reports study of 800 paired samples of indoor and outdoor smoke and SO2 concentrations of 60 Rotterdam homes. Finds that smoking increased the amount of smoke found in living rooms and the data suggest that newer houses tend to have less SO2 in the living rooms than older houses. On average living rooms contained approximately 80% of the smoke and 20% of the SO2 measured simultaneously outdoors during 24 hour periods. Estimates probability of having more SO2 in the living room than outdoors is less than 2%.

Reports field monitoring program by the Lawrence Berkeley Laboratory to assess the potential impact of reduced ventilation of indoor air quality. Three houses, designed to be energy-efficient, were monitored using a mobile laboratory. Parameters measured included infiltration rate, CO2, CO, NO2, NO, O3, SO2, HCNO, total aldehydes and particulates.

Reports study to investigate the possibilities of purifying air from formaldehyde by using a filter that brings the air into contact with an adsorbent substance. Finds that the type of adsorbent substance that works satisfactorily is that which involves adsorption in combination with the oxidation breakdown of adsorbent substances. Compares costs for residential premises between a) an increase in ventilation and the use of a heat exchanger and b) the type of air purification and recirculation describes above.

Describes sources of radon in materials and measures of exposure. Reviews measurements of radon in mines and dwellings. Describes measurements of the concentration of radon in a sealed chamber. Concludes that concentration of radon daughters can be reduced by removing dust from the air using an electrostatic precipitator or by using a very high ventilation rate combined with an efficient heat exchanger. Finds most significant sources of radon in dwellings are cracks and openings in the floor. Suggests reducing radon by covering bare surfaces and sealing the floor, or using a crawl space.