A public ASHRAE Journal podcast hosted a panel discussion where experts discuss the critical topic of protecting building occupants from smoke during wildfire and prescribed burn events. This is part three of a seven-part series.

…continued from part two.

Part three of seven. Image by Storyset on Freepik

Part three of seven. Image by Storyset on Freepik

The panel consists of:

  • Daniel Bourque, host and professional engineer from Halifax, Canada
  • Greg Nilsson, technical officer at the National Research Council of Canada. He actively researches technologies enhancing indoor air quality, with a specific focus on wildfire smoke since 2017
  • Rebecca Schmidt, a professor and molecular epidemiologist at the University of California. She studies the health effects of various exposures during pregnancy, including wildfire smoke and air quality issues

The conversation shifts to the proliferation of low-cost sensors and their potential use during wildfire events. Bourque acknowledges the emergence of affordable sensors, typically utilising online dashboards. He emphasises that these sensors, often priced below USD1 000, provide a baseline understanding of air quality. Nilsson notes that while the sensors can overestimate, they offer valuable data for comparing baseline air quality to periods of heightened pollution, such as wildfire events. The focus is on relative measurements within the same space.

Bourque addresses the question of the reliability of low-cost sensors compared to high-grade instruments used by agencies like the VAQH in Canada and AQa in the US. He explains that high-grade instruments, traceable to the National Institute of Standards and Technology (NIST), undergo rigorous quality control. Despite potential limitations, low-cost sensors serve a purpose in highlighting changes and providing a relative measure of air quality.

The discussion broadens to the integration of sensors in buildings, referencing the prevalence of CO2, occupancy and VOC sensors. While particulate sensors are gaining attention, Nilsson notes that studies with high-grade instruments can be impractical in certain settings. Affordable sensors are becoming valuable tools for building researchers, allowing for broader field studies and cross-comparisons with high-grade instruments.

Understanding VOCs and Total VOCs (TVOCs)

Bourque raises a point about the term VOCs (volatile organic compounds) and corrects it to TVOCs (total volatile organic compounds). He questions Schmidt about the potential harm of specific components in wildfire smoke. Schmidt clarifies that the guideline focuses on particulate matter, a key component in both urban smog and wildfire smoke. She emphasises that while VOCs are present, the primary concern is reducing exposure to particulate matter for health reasons.

Schmidt delves into the complexities of measuring TVOCs, highlighting the precision required for accurate readings in parts per billion to parts per trillion. While low-cost sensors can provide a relative idea of changes, she stresses the importance of due diligence in establishing baselines. Nilsson adds that understanding daily routines and noting significant deviations can inform necessary improvements in indoor air quality.

In this segment, the conversation delves into the practicality and reliability of low-cost sensors, their role in building research, and the challenges of measuring TVOCs. As ASHRAE guideline 44P continues to shape the discourse around protecting building occupants from wildfire smoke, the importance of leveraging available sensor technology becomes increasingly evident.

Continued in part four…


Live webcast on ASHRAE website