AIVC - Air Infiltration and Ventilation Centre

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air quality

Heating system-generated indoor air pollution

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.

Measurements of ionising radiation doses in dwellings in Poland. Pomiary promieniowania jonizujacego w niektorych budynkach mieszkalnych wPolsce

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.

Outdoor sources of indoor air pollution.

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.

Environmental radiation background variations between residences.

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.

Openings and ventilation for buildings.

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.

An experimental determination of ventilation rate in occupied rooms using atmospheric carbon dioxide concentration

Describes tests in Exeter University library of method of determining ventilation rate by measuring the amount that the atmospheric carbon dioxide concentration in an occupied space is raised above the outside ambient level. Compares rate obtained with that expected from the fan rating. Demonstrates that in addition to the ventilation rate, the average rate of production of carbon dioxide produced by the occupants could in principle have been estimated from the data.

Application of mathematical model for the buildup of carbon monoxide from cigarette smoking in rooms and houses.

Uses Turk's equation to obtain CO concentration v time curves in an office and a one-family house. Compares results with similar studies, current threshold limit values and ambient air quality standards for CO. Finds model is apparently valid for CO and probably for other gaseous contaminants not affected by absorption or deposition. Concludes that commercial environments should have at least 5 cfm fresh air per occupant and that a value of 50 cfmfresh air appears to be adequate for a one-family dwelling.

Source and importance of air pollution in the interior of buildings. Source et importance de la pollution de l'air a l'interieur des batiments.

Describes a sampling programme which measured simultaneously the indoor and outdoor concentrations of pollutants at three sites in Zurich during summer and winter. Gives brief summary of results showing concentrations of CO, NO, NO2 and HCHO and discusses sources of the different pollutants.

Practical methods of reducing airborne contaminants in interior spaces.

Air contaminants include all gases, vapours, liquid droplets and solids, including microogranisms of small size that can be dispersed in air and that are unwanted. Contaminants can be removed by dilution of the air, by deposition of particles on surfaces or by reaction with other materials in air or in space (such as furnishings).< This article discusses in general terms the reduction of contaminants and gives equations of concentrations of contaminants after time t. Discusses types of filters and their effectiveness.

Standards for natural radioactive substances in building materials. K voprosu o normirovanii soderzhaniya estestvennykh radioaktivnykh veshchestu v stroitel'nykh materialakh.

Discusses mechanisms for radon liberation in dwellings. Mentions survey which found radon concentrations exceeding the maximum permissable concentration of 3 x 10^-12 curies in 13 of the 65 dwellings. Gives expressions for number of radon atoms in indoor air at time t and activity due to radon per unit volume. Discusses liberation of radon from walls and from soil and concludes that if the ventilation is poor or if there is a high emanation of radon, the indoor radon concentration may approach the maximum permissable level.