| Summary: | To mitigate the effects of climate change, building decarbonization and energy efficiency measures have expanded in scope. At the same time, interest has grown in how these changes affect indoor air quality (IAQ) and thus personal health.
This thesis analyzes the concentrations of gas pollutants and particulate matter (PM) within occupied apartments in two New York City affordable housing projects, which we will refer to as Bushwick and Woodlawn. At Bushwick, we explore how gas and PM concentrations are impacted by retrofits that decarbonize the building and increase its energy efficiency to meet passive house standards. At Woodlawn, we monitor PM in a new development built to passive house standards to observe how concentrations are impacted by occupancy and controlled changes to ventilation and filtration settings.
Results at Bushwick were limited by the availability of data and confounding factors but indicated the potential for a retrofit to passive house standards to improve IAQ. PM and gas sensors were initially installed in four apartments, but only one apartment (Apt. D) maintained both of these sensors online throughout the study. In addition, one apartment (Apt. A) kept only the PM sensor online and another (Apt. B) kept only the gas sensor online. This ultimately allowed us to analyze changes in PM and gas concentrations in two apartments each. Of note, a few tenants in Apt. D who used to smoke in the unit moved out during the retrofit, so these changes confounded any effect of the retrofit on air pollution that we hoped to observe. We observed statistically significant decreases in most gas and PM pollutants across apartments following the retrofit. PM1 saw the most steep decreases in PM, with mean concentrations dropping 55% in Apt. A and 44% in Apt. D after the retrofit. Amongst gases, mean CO2 concentrations decreased by 62% in Apt. B and 45% in Apt. D. This decrease in air pollution resulted in greater compliance with Health Canada IAQ guidelines after the retrofit.
Results at Woodlawn were supported by strong data collection for a year in nine apartment units. By observing air pollution before and after tenants moved in, we determined that occupancy had a statistically significant effect in increasing PM concentrations in all observed apartments. We also observed that the combined effect of increasing ventilation rates by 25% and using in-unit HEPA filters resulted in statistically significant decreases in PM concentrations across most units. Across all interventions in occupancy, ventilation, and filtration, PM2.5 and PM10 concentrations in all units fully complied with WHO ambient air quality guidelines. Furthermore, air pollution indoors was consistently lower than that outdoors, evidence that passive house construction can keep indoor air quality high and protect residents from outdoor air pollution.
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