air quality

Notes that indoor air can contain between 01 - 100 x 10\9 ppm particles and that sub-micronic particles (1 -100 micro m) dominate. Defines indoor as microbiological laboratories, public buildings including the stations, nurseries, cinemas etc. and dwellings. Lists sources of pollution and tabulates limit values for aerosols noting those which are carcinogenic, absorbed through the skin, allergy-producing. Maximum limits stated are for 15 min/hour exposure rate. Discusses risks involved and how injury can be prevented.

A review of literature reporting investigations of pollution in enclosed spaces. Discusses pollution in sealed environments such as submarines, the relation of indoor to outdoor pollution, sources of indoor pollution, and tobacco-induced pollution. Outlines problem of pollution in transportation- related enclosures such as tunnels, subways and garages. Suggests that indoor pollution in public office buildings is of greater potential harm than outdoor pollution. Gives 18 tables summarising measurements of various indoor pollutants made by different studies.

Reports 100 measurements of formaldehyde content of the indoor atmospheres of 25 rooms in 23 dwellings, mainly in new or recent one-family houses with varying quantities of particle board. The formaldehyde content in the indoor atmosphere averaged 0.63 mg per cubic metre of air with a range from 0.08 to 2.24. concentrations in two rooms were higher than permitted uppervalues for workshops (1.2), in 17 rooms the values were higher than a calculated value for long-term exposure (0.4) and in eight rooms the values were lower than this.

Discusses the problem of increased levels of indoor air pollution due to reduced ventilation. Suggests ways of lowering pollutant concentrations without compromising energy conservation. One promising method is to mechanically ventilate a residence and recover heat from the exhausted air with an air-to-air heat exchanger.

Outlines problem of radon in buildings and current state of knowledge. Suggests reduction of radon by a) more efficient ventilation, b) use of diffusion resistant films to seal wall surfaces and c) elimination of certain active materials. A research project at the Swedish Council for Building Research is currently investigating the problem.

Discusses in detail a general ventilation model, which relates indoor pollutant concentrations to those outside. When the time interval associated with changes in the outdoor concentration islong compared to that required either to change the air within the building or to remove the pollutant by internal means, the indoor concentration of pollutant can be related to the outdoor concentration by means of a simple expression. Finds good agreement between theory and experiment. Suggests method for reducing indoor ozone levels in California.

Reports study of indoor climate-primarily air quality-and energy consumption in a number of detached houses in a group housing area. All the houses were pressure-tested over three years; 1977-1980 and a relatively larger increase in air leakage was measured after the houses had been occupied for approximately one year. Suggests this is due to the drying out of timber, producing cracks. Two types of houses, a and b were investigated when studying indoor climate. both were mechanically ventilated.

Considers the rate of natural ventilation required in a room to maintain a healthy concentration of oxygen given the efficient sealing of windows against draughts. Includes a nomogram toassist the calculation of a rate of air introduction according to the height of the building, wind loads, and type of window construction.

Gives regulations and performance guidelines for the ventilation of buildings. Includes guidelines for air quality and gives recommended supply and return air volumes for different rooms of a building.

Reports measurements of air pollutants inside and outside three pairs of structures for different seasons of the year. Four pollutants were measured, suspended particulate, soiling particulate, carbon monoxide and sulphur dioxide. Describes instrumentation and gives results. Concludes that in homes withgas heating and cooking, the heating system has no effect on CO levels but gas stoves had a significant effect.