air quality

For controlling and for setting ventilation standards to maintain acceptable indoor air quality, it would appear to be of greatest importance to determine the strength of relationships between contaminant concentrations on one hand and different rates of ventilation and how these rates are expressed on the other.

Measures of a number of ventilation parameters and of a number of pollutants from 21 locations furnished data for evaluating interrelations among commonly used descriptors of ventilation as well as their relation to frequently measured indoor gaseous and particulate pollutants.

Data on indoor/outdoor pollutant and tracer concentrations were collected during different periods in 1981 at a residence in Newton, MA. 

A subcommittee of the Nordic Committee for Building Codes has released guidelines for building regulations regarding indoor air quality, especially concerning ventilation. The main features of the guidelines, such as acceptable outdoor air quality for ventilation and minimum outdoor air flows for dwellings and offices, are presented and discussed. Mechanical ventilation is, in principle, required in all buildings including dwellings, due to therequirement of a minimum outdoor air change of 0.5 h-1 and the normal highly airtight nature of new buildings.

Discusses the nature of the problem of indoor air pollution, limitations in the authority of established health agencies in the US to control the problem, research needs and some control options. Indoor pollutants of current concern include radon, tobacco smoke, emissions from unvented indoor combustion appliances, aeropathogens, formaldehyde and pesticides.

Efforts to reduce the energy needs to heat or cool dwellings have the potential to create new health hazards. Increases in indoor levels of radon and its progeny from the reduction in air exchange rates add a substantial radioactive burden to the general population. Other indoor pollutants reaching critical concentrations in homes with low air exchange rates are CO and NO2 from unvented combustion in gas stoves and heaters, tobacco smoke, and asbestos fibres.

An increasing incidence of 'building illness' is being noted among white-collar workers due to the high pollutant content of air in modern energy-efficient office buildings. 

Discusses the established principles and rules of air hygiene for animal housing and areas in which guidelines have yet to be devised. The most common pollutants are ammonia, hydrogen sulphide, methane and carbon dioxide. Dust and aerial microbial flora also have to be considered. Ventilation criteria for pigs and poultry and for cattle, sheep and horses are discussed. The current threshold limiting values for noxious gases and inert dust which could be used in the design and operation of livestock buildings are based on studies of humans rather than farm animals.

The objectives of a ventilation system are to provide an aerial environment in which 1, animals' health and productivity can be maintained, 2, the stockman's comfort and health needs are satisfied, and 3, the building and equipment are protected from damage. Criteria for evaluating ventilation include: thecontrol of air temperature and air speed at animal height, the control of relative humidity and prevention of condensation, and the maintenance of tolerable concentrations of gases, dust, and airborne microorganisms.

Particulate and gaseous emissions from indoor combustion appliances.and smoking can elevate the indoor concentrations of various pollutants. Indoor pollutant concentrations resulting from operating one or several combustion appliances, or from sidestream tobacco smoke, were measured in a 27m3 environmental chamber under varying vent ilation rates. The combustion appliances investigated were gas-fired cooking stoves, unvemed kerosene--fi red space heaters, and unvented natural gas-fired space heaters.