United States of America

Residential cooking can be a significant indoor source of odour, pollutants and particulate matter. Conventionally, range hoods expel the air into the ambient. A number of studies have investigated their contaminant capture performance. However, for highly energy efficient houses the installation of extracting range hoods can pose certain challenges, e.g. high ventilation losses, additional thermal bridges and potential air leakage sites.

In 2008 the State of California adopted new building codes that required the use of mechanical ventilation systems in homes that meet the requirements of ASHRAE Standard 62.2. The standard requires both a dwelling unit mechanical ventilation system and exhaust fans in kitchens and bathrooms. A field study was undertaken to evaluate the IAQ and ventilation performance of homes built to these requirements. For ventilation system performance, the airflows of all mechanical ventilation systems were measured and their use was monitored for a one-week period.

A key aspect of achieving acceptable indoor air quality is source control. Cooking has been recognized as a significant source of pollutants for health impacts (e.g., PM2.5 and NO2) as well as moisture and odour. A common method of controlling this pollutant source is by using a range (or cooker) hood that vents to outside. However, field and laboratory experiments have shown highly variable performance for these devices. We use the capture efficiency metric (the fraction of the pollutants that are exhausted to outside at steady state) to characterize the range hood performance.

Indoor carbon dioxide (CO2) concentrations have been used in the fields of building ventilation and indoor air quality (IAQ) for decades. Specific applications include the estimation of ventilation rates, control of outdoor air ventilation rates based on indoor CO2 as an indicator of occupancy, and use of CO2 as an IAQ performance metric. All of these applications require values for the CO2 generation rates of the occupants of the space or building being considered. Human CO2 generation rates depend on their level of physical activity as well as their sex, age, and body size.

The first ASHRAE IAQ conference in 1986 was held “to review the latest research in indoor air pollution and provide missing current data for Standard 62” with the understanding that, “the indoor environment should minimize any impact on health and should be free of any impact on comfort, and control should minimize the use of energy.”1 Implicit in this statement is the belief that the performance measures needed to realize this goal could be defined in practical terms.