AIVC - Air Infiltration and Ventilation Centre

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air quality

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.

Assessment of airborne radon daughter concentrations in dwellings in Great Britain.

Calculations of the activity concentration of RaA (218 Po) in the air within living rooms and in the outside air were made at 87 dwellings in England and Scotland. From these measurements together with a determination of the ventilation rate existing in the room at the time of the measurements, the rate at which 222 Rn is emanating from room surfaces into room air in pci/l/h can be calculated.

Natural radiation in the urban environment.

Summarizes previous work on natural background radiation levels and reports some new data from Boston Mass.

The effect of smoking on ventilation requirements.

Reports measurements of suspended particulate matter, carbon monoxide and droplet nuclei in a climate chamber of 50m3 as indicators of the particulate and gaseous phase of cigarette smoke. Various combinations of smoking intensities andventilation rates between 1 and 16 air changes per hour were investigated partly by a standardized smoking machine procedure and by individual smoking by a panel of four persons.

Radon committee proposes provisional limit values and better ventilation. Provisoriska gransvarden och battre ventilation foreslar radonutredning.

Reports first report from committee, "Preliminary proposals for measures against radiation risks in dwellings". Notes that prime source of radiation, alum-based lightweight concrete, has been banned in new buildings in Sweden, but is still present in 10%of pre-1975 houses. Provisional limits for gamma radiation for undeveloped sites: 30-100 micro.r/h (site should only be built on subject to other conditions), more than 100 micro.r/h (building inadvisable). suggests that geological radiation maps be charted. Notes reduction in radon content through house ventilation.

Radon in buildings, a hygiene problem caused by radiation. Radon i boliger, et stralehygienisk problem.

Investigation has shown connection between radon content in mines and lung cancer in miners. Radon is also present in building structures. Presents measurements carried out inNorwegian houses and discusses consequences of radiation doses absorbed in human lungs as well as biological effects of background radiation. Diagram illustrates concentration of radon in concrete, brick and wood. Analyses factors which affect radon content, particularly barometric pressure and ventilation rates.

Particulate pollution in indoor air Partikulara Fororeningar i inomhusluft

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.

Exposure to pollutants in enclosed "living spaces".

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.

Formaldehyde in the atmosphere of danish homes. Formaldehyd i indeluft i danske boliger.

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.