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Day One Summary
To conclude the first day of the workshop, planning committee member Jeffrey Siegel (University of Toronto) recounted some of the themes that cut across several of the presentations. The first was that when considering indoor fine particulate matter, it is important to account for precursors and other things that can modify PM2.5, such as the presence of vapor-phase material that can condense into particulates. He named five broad categories of influential factors: situational, building and HVAC, activity and mobility, occupant perceptions and behavior (noting that how people perceive the risks associated with particulate matter might modify their behavior, leading to changes in exposure and even how much is generated), and measurement. It was important to remember, he emphasized, that these factors cut across indoor and ambient particulate matter and were interrelated, not independent of one another.
Siegel noted a strong sentiment among the speakers for addressing the underlying causes of exposure disparities. This is, as Ivey observed, a systemic problem that requires systemic solutions, and the hunt for those solutions should be a primary driver of research needs.
Throughout the day, the speakers identified the need for research to
- Resolve exposure misclassification that arises from a lack of information about how the transport of ambient PM2.5 to the indoors might change exposure.
- Develop health-relevant metrics and examine PM2.5 exposure through the lens of what matters most to human health.
- Identify the chemical processes, deposition processes, and sinks that affect indoor particulate matter in general and PM2.5 in particular.
- Measure unknown input parameters that go into models in order to apply the models more broadly.
- Characterize the composition of indoor PM2.5 and the drivers that produce specific types of particulate matter.
- Explore the interactions between indoor PM2.5 and the indoor microbiome.
Corsi closed the session by thanking the speakers and other participants for their contributions.
