IAQ 2016 Defining Indoor Air Quality: Policy, Standards and Best Practices Co-Organized by ASHRAE and AIVC

The National Institute of Standards and Technology (NIST) constructed a Net-Zero Energy Residential Test Facility (NZERTF) to support the development and adoption of cost-effective NZE designs and technologies. Among the key objectives in designing the facility was the health and comfort of the occupants by providing adequate ventilation and reducing indoor contaminant sources. To improve source control, guidelines were implemented to utilize products with relatively low volatile organic compound (VOC) emissions. Indoor and outdoor concentrations of formaldehyde and 30 other VOCs were measured approximately monthly during two years of house operation. Measurements were taken under normal house operating conditions as well as with the ventilation system off and during elevated indoor temperatures. IAQ and energy measurements were used to validate the IAQ and energy results of a coupled CONTAM-EnergyPlus model. The validated model was then used to evaluate the IAQ and energy consequences of various source control and ventilation strategies. The results of this work demonstrate the need for appropriate product selection (source control) and mechanical ventilation in tight, NZE homes.

Radon is the second-highest leading cause of lung cancer, after smoking, in many countries, and associated with increased risk of leukemia and multiple myelomas have been documented. In an OECD survey of 30 countries, Ireland was found to have the eighth-highest average indoor radon concentration. In Ireland, radon results in over 56% of the population’s radiation exposure, accounting for up to 250 cases of lung cancer each year. There is no recognized threshold below which radon exposure presents no risk. Recent research shows that energy retrofitting of dwellings may lead to greater airtightness and increased indoor air pollutant concentrations, and there is a possibility that radon concentrations may also increase. A knowledge gap has been identified that the relationship, if any, between improved energy efficiency in buildings and indoor radon concentrations is not well understood. This study aims to fill this knowledge gap by collecting and analyzing existing literature-based data, and using this data as the basis for a complementary computational study of the implications for ventilation and for radon concentration of a number of energy efficient retrofit scenarios, relevant to the Irish building stock. A computational model will be validated against data from an experimental case study where radon measurements pre and post retrofit are being carried out. Once validated, simulations will contribute to the filling of a number of knowledge gaps identified, specifically (i) a lack of data on radon in buildings that have undergone an external insulation energy retrofit (ii) estimate radon concentrations in retrofitted buildings, incorporating a range of initial radon concentration scenarios and retrofit strategies (iii) provide recommendations for future policy surrounding the appropriate management of energy efficient retrofitting so that acceptable indoor air quality levels (to include radon) are maintained.

One in four Minnesota middle school students report that they have ridden in a car with someone who was smoking cigarettes in the preceding week (Minnesota Youth Tobacco and Asthma Survey, 2011), yet only eight US states have policies prohibiting smoking with youth in vehicles (www.no-smoke.org). This study expands on previous research by measuring ventilation rates and secondhand smoke particulate concentrations under a variety of conditions that affect passenger exposure. A total of 170 trials were conducted, including duplicate trials to determine reliability. The monitoring included continuous photometer measurements of fine particles (PM_2.5) before, during, and after a participant drove and smoked a cigarette. The instruments were installed in 3 to 5 locations inside the vehicle and 1 outside to measure and compensate for ambient air particulates. Carbon dioxide injection and decay were used to compute the ventilation rate and the PM_2.5decay rate was analyzed to determine the total removal rates that included ventilation and absorption. The monitoring was conducted for 3 vehicle types (sedan, mini-van, SUV), 2 driving speeds, 4 window positions, and multiple ventilation operating conditions over both summer and winter conditions. With windows closed and the vent fan on, the average PM_2.5 concentration during smoking ranged from 138 to 2,694 with an average of 1,020 ug/m³. After smoking stopped, it took from 4 to 25 minutes for the particulate level to decrease to the background level. When the activate smoking and post-smoking periods were combined, the passenger’s total PM_2.5 exposure averaged 165 ug/m³ * hr. The average exposure was 61% higher for city driving (30mph) than highway driving (60mph). The exposure in the rear seats compared to the front varied with window position. Overall, for about half of the trials, the SHS concentration was greater in the rear seats than in the front passenger seat. Opening windows greatly increased ventilation and reduced exposure levels. Opening windows just 2 inches reduced exposure by almost an order of magnitude and fully opening at least one window reduced exposure by a factor of 34.