air quality

A pilot study was conducted using workers from a semiconductor plant. Describes the methods used to acquire and evaluate air pollution exposure data for significant environments (including workplace, in-transit, and residence) to which workers are exposed throughout a typical 24-hour day. Summer andwinter measurements were made on products of combustion, radon, respirable particulates, and a variety of organic compounds including methylene chloride.

The Harvard School of Public Health and the Energy and Environmental Policy Centre of the Kennedy School of Government, under the auspices of the Electric Power Research Institute and the Gas Research Institute, conducted a"Workshop on Evalu

In 1981 Norwegian building regulations introduced quantitative requirements to air leakages in different types of buildings. The requirements were formed as maximum allowed air changes per hour at 50 Pa pressure difference according to the pressurization method. To evaluate the consequences of these new requirementsimposed to Norwegian building industry a model proposed by the Nordic Committee for Building Regulations (NKB) was used. The average air leakages of residential buildings , built before the new requirements,are known through a research project performed i n 1979.

The air infiltration associated with ventilation in buildings is recognized in ASHRAE Standard 62-1981, Ventilation for Acceptable Indoor Air Quality. In the light of recent trends toward increasingly tight housing, which limits air infiltration for ventilation, dependence on this source of outside air is onepoint that must be carefully considered in the Revised Standard. Other points to be considered are ventilation efficiency, necessary dilution of particulates and other pollutants, and how changes in humidity, air temperature and local heating may alter pollution levels in buildings.

Eleven countries are cooperating to establish guidelines for minimum ventilation rates which are sufficiently large to meet the demand for outdoor air in buildings without unnecessarily wasting energy. The most important pollutants have been identified as: carbon dioxide, tobacco smoke, formaldehyde, radon, moisture, body odour, organic vapours and gases, combustion products and particulates. To a certain degree some of thesesubstances can be used as indicators for acceptable air quality to establish minimum ventilation rates.

Reduction of fresh air ventilation is becoming the major means of energy conservation in office buildings. Simultaneously, health and comfort problems experienced by occupants are often suspected to be a direct result of reduced fresh air ventilation. However, there is little data available on health and comfort problems experienced by occupants of buildings operated under normal ventilation rates.

Ventilation standards in buildings are receiving increased attention because of energy conservation and indoor air quality. An important example of this is the current ASHRAE Standard 62-1981, "Ventilation for Acceptable Indoor Air Quality." This standard contains two distinct procedures that can be used to set ventilation rates. The first is a prescriptive specification that mandates ventilation rates for particular building types. The second is a performance specification that uses target concentrations of indoor contaminants as the basis for deciding the adequacy of ventilation rates.

In Finland there are not yet any regulations or standards concerning the airtightness of buildings. Drafts have caused discussion about whether controlled airtightness would increase the building costs too much, and improved airtightness worsen the indoor air quality. In modern Finnish buildings a good or satisfactory airtightness can be achieved with normal careful workmanship. To secure good indoor air quality, a functioning ventilation system is also necessary. There seems to be no return to traditional 'breathing' structures and natural ventilation.

An investigation of the minimum fresh air supply per person required to prevent the occurrence of unacceptably offensive odour due to stale air in offices and similar buildings. The study was made under everyday conditions as far as possible, in different buildings, various size rooms, different densities of occupancy, with men or men and women, and with mechanical or natural ventilation.

One option of reducing residential energy consumption is to improve air tightness but adequate ventilation must be provided for health reasons. Sources of infiltration and factors affecting infiltration rates are described, with methods for quantifying and comparing rates. The relationship with air quality is explained and the effect that air quality has on respiration and health. Typical indoor pollutants are carbon monoxide, carbon dioxide, nitrogen oxides, radon and radon progeny, formaldehyde gas, particulates, tobacco smoke and odours.