What has heat recovery done for the cause or energy efficiency? If some manufacturers or heat recovery equipment are to be believed, the savings in ventilation costs are "quite staggering".

To ensure prompt response by real-time air monitors to an accidental release of toxic aerosols in a workplace, safety professionals should understand airflow patterns. This understanding can be achieved with validated computational fluid dynamics (CFO) computer simulations, or with experimental techniques, such as measurements with smoke, neutrally buoyant markers, trace gases, or trace aerosol particles. As a supplementary technique to quantify airflows, the use of a state-of the art, three-dimensional sonic anemometer was explored.

When a person is located in a contaminant field with significant gradients the contaminant field will be modified locally due to the entrainment and transport of contaminated air in the human boundary layer as well as due to the effect of the person acting as an obstacle to the flow field, etc. In this paper personal exposure measurements are performed by means of the Breathing Thermal Manikin. Contaminant concentration is measured in a number of locations in the breathing zone and in the inhaled air.

     Nothing highlights construction shortcomings like severe winter storms. Too often, possible problems are neglected during the construction season when winter and its bad weather seem far removed. The winter of 1999 produced many ice dams on shingle roofs in central and eastern Canada. The resulting leaks caused widespread damage to ceilings, walls and interior .furnishings of many homes.     

This study investigated the presence of allergens such as dust and molds in heat recovery ventilation systems and the duct work. It also looks at two different types of cleaning equipment and their ability to clean these pollutants from the rigid and flexible ductwork and heat recovery ventilator (HRV) cores in dedicated balanced supply and exhaust ventilation systems. Samples from the ductwork and cores of ten ventilation systems were tested for levels of dust and mold.

Three different techniques for reducing exposure to microorganisms were tested during remediation of moldy buildings. Concentrations of spores (fungi and actinomycetes) were determined by filter sampling before, during, and after remediation. The local exhaust method used for asbestos dismantling was the most effective control method. In the construction zone, concentrations of microorganisms were 4-25 times higher during remediation than before it. In the adjacent area no increase in concentrations was seen.