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

Exposure to fine particulate matter (PM2.5) has been identified as a significant public health issue. PM2.5 of outdoor origin accounts for around 50% of indoor PM2.5. Reductions in exposure to PM2.5 of both outdoor and indoor origin can be made in new and existing residential buildings. The practicality of reducing indoor exposures to PM2.5 of outdoor origin by applying airtightness in combination with filtered outdoor air to slightly pressurize new and existing residential buildings is discussed. Potential reductions of exposure to cooking related PM2.5 by applying the information to the design and installation of range hoods is also discussed.

We will summarize the content of a Residential IAQ Guide ASHRAE is developing, scheduled for release in 2017. It will serve as guidance for achieving good IAQ through source control, ventilation and air cleaning. Principles are based on research findings “boiled down” to actionable and concrete form.

The presentation addresses all who influence the residential environment: architects, engineers, homebuilders, construction contractors; quality control professionals (commissioning); organizations; homeowners, residents and operators. This new publication supplements Indoor Air Quality Guide: Best Practices for Design, Construction and Commissioning, published in 2009, which was targeted primarily a non-residential audience.

Time-resolved concentrations of nitrogen dioxide (NO₂) and particles were measured during and after scripted use of natural gas cooking burners in 9 California residences. Cooktop, oven, and broiler burners were operated to simulate food preparation. In most homes, the highest NO₂ concentrations in the kitchen exceeded the US EPA’s standard of 100 ppb. Highest 1h concentrations of NO, NO2, and particles in a distant location were often 50% or less of those in the kitchen. Use of venting range hoods substantially reduced concentrations in all 5 homes in which they were tested, though effectiveness varied greatly.

In this presentation, we give an overview of ventilation in new New Zealand houses. At least 10% of New Zealand houses have a positive pressure mechanical ventilation system installed, generally pulling air from the roofspace cavity into the living spaces. We will discuss an in depth measurement and modelling study of two newer houses of timber frame construction with brick cladding and a corrugated iron roof that had positive pressure mechanical ventilation systems installed. The implications of moisture transfer from roofspaces into living spaces and of moisture condensation in houses with positive pressure mechanical ventilation systems will be discussed.