air quality

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.

Presents model of indoor pollution that assumes a linear relation between indoor pollutant levels and the air change rate. Discusses effect of heating system and cooking on pollutant levels and ventilation rate. The model predicts that when air change rate is reduced 4-fold, heating systems pollutant contributions can still rise up to 3-fold despite the saving in energy from reducing ventilation. Suggests precautions are necessary when tightening building envelope. Recommends that pilot lights be eliminated and effective kitchen ventilation systems installed.

Gives general discussion of sources of radon gas and its daughter products. Reviews measurements made of radon concentrations in air. Outlines control strategies for limiting radon in buildings.

Heating systems may emit pollutants into living spaces of buildings. Presents model for estimating exposure to pollutants allowing for variation of air change rate and inside-outside temperature differences. Examines the effect of energy conservation measures. Concludes that if ventilation alone is reduced the pollutant concentrations will rise but if reduced ventilation is balanced by increased insulation then pollutant contributions will remain unchanged. The analysis applies only to pollutants generated by the heating system.

A portable background gamma-radiation dosimeter with a high-pressure ionization chamber was designed. The gamma background radiation dose rate and radon concentration in the air of the 97 new flats were measured. The flats were selected in the houses of the experimental settlement in Suzewiec (quarter of Warsaw), of three settlements of Kodz, and of five settlements of the upper silesian industrial area. For the construction of these settlements building materials typical for new constructions in Poland were used, such as products derived from metallurgical wastes like slag or boiler ash.

Points out that conservation measures such as storm windows which seal a building protect occupants from outdoor air pollution but amplify effects of pollution generated indoors. Considers which effect is greater. Develops a model relating indoor air pollutant concentrations to outdoor concentrations and to v, the air exchange rate, which is consistent with reported behaviour of common pollutants. Model predicts that indoor concentrations follow outdoor concentrations but maxima and minima lag behind, and are not as pronounced as theiroutdoor counterparts.

Reports environmental background radiation exposure measurements made in approximately 100 residences in the vicinity of Livermore, California showing variations in annual exposure from 52 to 130 mr. Measurements were made with CaF2:Dy (tld-200) dosimeters at quarterly intervals for a period of 1 year. Dwellings were typically wood-frame structures with stucco exteriors. Interior exposure rates were, on average, about 25% lower than those outdoors.

Describes the basic relation between pressure difference and air flow rate across an opening under steady state conditions. Taking the ventilation system into account, the pressure difference pattern across building enclosures andthe air leakage characteristics of exterior walls, interior separations and various service shafts must be understood, but at present little of this information has been available for actual buildings. Presents new data on the air leakage characteristics and natural ventilation rates for sound insulating houses.