Development and application of an indoor carbon dioxide metric.

Indoor carbon dioxide (CO ) concentrations have been considered for decades in evaluating indoor air quality (IAQ) and ventilation, and more recently in discussions of the risk of airborne infectious disease transmission. However, many of these applications reflect a lack of understanding of the connection between indoor CO levels, ventilation, and IAQ. For example, a single indoor concentration such as 1000 ppm is often used as a metric of IAQ and ventilation without an understanding of the significance of this or any other value.

Oxidative Potential of Particles at a Research House: Influencing Factors and Comparison with Outdoor Particles.

The oxidative potential (OP) of particles can be represented by the ability of particles to generate hydroxyl radicals in an aqueous solution which can be measured with electron paramagnetic resonance (EPR) spectrometry. The oxidative potential of particles may be a more health-relevant metric than other physicochemical properties of particles. While OP has been measured in several outdoor locations, it remains largely unstudied in indoor environments.

Estimating real-time infiltration for use in residential ventilation control.

Minimum outdoor air ventilation rates specified in standards such as ASHRAE Standard 62.2 are generally based on envelope airtightness, building floor area, geographical location, and number of occupants. ASHRAE Standard 62.

Challenges in Developing Ventilation and Indoor Air Quality Standards: The Story of ASHRAE Standard 62.

Building ventilation has long been recognized for its role in occupant health, comfort and productivity, with some of the first recommendations on building ventilation rates published in the 19 century. These recommendations were subsequently transformed into more rigorous standards and guidance in the 20 century, with the first version of ASHRAE Standard 62 published in 1973. Since that time, ventilation standards have been issued in several countries around the world and have dealt with an increasingly complex and challenging range of issues as research on indoor air quality and the state of knowledge of building performance have progressed.

Ultrafine particle removal and ozone generation by in-duct electrostatic precipitators.

Human exposure to airborne ultrafine particles (UFP, < 100 nm) has been shown to have adverse health effects and can be elevated in buildings. In-duct electrostatic precipitator filters (ESP) have been shown to be an effective particulate control device for reducing UFP concentrations (20-100 nm) in buildings, although they have the potential to increase indoor ozone concentrations. This study investigated residential ESP filters to reduce ultrafine particles between 4 to 15 nm and quantified the resulting ozone generation.

Standard formaldehyde source for chamber testing of material emissions: model development, experimental evaluation, and impacts of environmental factors.

Formaldehyde, which is recognized as a harmful indoor air pollutant for human health, is emitted mainly from urea-formaldehyde resin in wood products. Chamber tests are used to evaluate formaldehyde emission rates from these products. However, there is no available formaldehyde standard reference emission source to assess the performance of chamber testing systems.

Indoor ultrafine particles of outdoor origin: importance of window opening area and fan operation condition.

Inhalation exposure to ambient ultrafine particles (UFP) has been shown to induce adverse health effects such as respiratory and cardiovascular mortality. Human exposure to particles of outdoor origin often occurs indoors due to entry of UFP into buildings. The objective of the present study is to investigate entry of UFP into a building considering building operational characteristics and their size-dependent effects on UFP concentrations.

Reduction of exposure to ultrafine particles by kitchen exhaust hoods: the effects of exhaust flow rates, particle size, and burner position.

Cooking stoves, both gas and electric, are one of the strongest and most common sources of ultrafine particles (UFP) in homes. UFP have been shown to be associated with adverse health effects such as DNA damage and respiratory and cardiovascular diseases. This study investigates the effectiveness of kitchen exhaust hoods in reducing indoor levels of UFP emitted from a gas stove and oven.

In situ experimental study of carbon monoxide generation by gasoline-powered electric generator in an enclosed space.

On the basis of currently available data, approximately 97% of generator-related carbon monoxide (CO) fatalities are caused by operating currently marketed, carbureted spark-ignited gasoline-powered generators (not equipped with emission controls) in enclosed spaces. To better understand and to reduce the occurrence of these fatalities, research is needed to quantify CO generation rates, develop and test CO emission control devices, and evaluate CO transport and exposure when operating a generator in an enclosed space. As a first step in these efforts, this paper presents measured CO generation rates from a generator without any emission control devices operating in an enclosed space under real weather conditions.

Infiltration of outdoor ultrafine particles into a test house.

Ultrafine particles (UFP) (<100 nm) have been related to adverse human health effects such as oxidative stress and cardiovascular mortality. However, human exposure to particles of outdoor origin is heavily dependent on their infiltration into homes. The infiltration factor (Finf) and its variation as a function of several factors becomes of enormous importance in epidemiological studies.

Contribution of gas and electric stoves to residential ultrafine particle concentrations between 2 and 64 nm: size distributions and emission and coagulation remission and coagulation rates.

Three indoor sources (a gas stove, an electric stove, and an electric toaster oven) of ultrafine particles (UFPs) have been studied in an instrumented test house on the campus of the National Institute of Standards and Technology (NIST). Previous studies have reported the concentration of ultrafine particles indoors due to cooking, but have been limited to particles with diameters greater than 10 nm. New technology now makes it possible to measure particles as small as 2 nm.

Development of a field test method to evaluate gaseous air cleaner performance in a multizone building.

The performance of gaseous air cleaners for commercial and residential buildings has typically been evaluated using test protocols developed for a controlled laboratory chamber or a test duct. It is currently unknown how laboratory measurements relate to the actual performance of an air cleaner installed in a real building. However, to date, there are no air cleaner field test protocols available, thereby limiting the existing field data.