English

Fungal spore content in dust accumulated in air ducts was investigated in 24 mechanically ventilated single-family houses of which 15 had also a central air heating system. Dust was collected from the ducts simultaneously with cleaning of the ventilation systems. Besides spore concentrations and flora of culturable fungi, total fungal spore concentrations were determined in dust samples by the aqueous two phase technique and spore counting with epifluorescence microscopy.

With environmental issues (such as high energy costs for air-conditioning and related C02 emissions and global warming) in mind, designers are increasingly considering natural ventilation as the primary design option. Naturally ventilated office buildings can typically consume less than half the delivered energy consumed in air-conditioned buildings representing cost-effective energy savings of the order of 20-30%.

A computational sensitivity analysis was conducted to identify the conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might most likely exacerbate or create back-drafting of natural-draft combustion appliances. Parameters varied included: house size; normalized leakage area; exhaust rate of exhaust appliances other than the ASD system; and the amount of house air exhausted by the ASD system.

The existing literature contains strong evidence that characteristics of buildings and indoor environments significantly influence rates of respiratory disease, allergy and asthma symptoms, sick building symptoms, and worker performance. Theoretical considerations, and limited empirical data, suggest that existing technologies and procedures can improve indoor environments in a manner that significantly increases health and productivity.

The paper is structured in four sections. The introduction sets the notion of solar control as a fundamental issue in deciding the priorities of climate-responsive design for different building types and locations in Europe. The second section presents an overview of application contexts and means of solar control, and discusses design priorities and threshold conditions for different space functions and environmental design requirements.