Search

Particle filtration can effectively reduce indoor concentrations of particulate matter (PM) but may incur high energy use. This study evaluates fixed and adaptive concentration thresholds to automate the operation of filtration systems. Simulated environments were derived from week‐long continuous PM measurements from Dylos DC1700 (N = 104) and Alphasense OPC‐N2 (N = 100) particle counters deployed in apartments in Toronto. A fixed threshold of 4.0 μg·m−3 resulted in a mean air cleaner runtime of 6.9%–21.0% depending on clean air delivery rate (CADR) and particle sensor, while providing mean concentration reductions of 67%–71% compared to operating the air cleaner constantly (runtime = 100%). In most environments, runtime could be further reduced by raising the fixed threshold while resulting in only a modest decrease in absolute and normalized mean exposure reduction. Using an adaptive threshold derived from a k‐means clustering approach generally provided substantial exposure reduction while preventing high runtimes. These results were generally insensitive to cleaning power and the monitor used to measure particle concentrations. Reducing the energy usage of particle filter systems will make them a more viable and sustainable means of improving occupant health. [ABSTRACT FROM AUTHOR]

Residents from low‐income social housing are vulnerable to adverse health effects from indoor air pollution. Particle‐bound concentrations of eight phthalates and 12 polycyclic aromatic hydrocarbons (PAHs) in indoor air were measured using quantitative filter forensics with portable air cleaners deployed for three one‐week periods from 2015 to 2017. The sample included 143 apartments across seven multi‐unit social housing buildings in Toronto, Canada, that went through energy retrofits in 2016. Eight phthalates and six PAHs were found in more than 50% of the apartments in either of the three sampling periods. Di(2‐ethylhexyl) phthalate (DEHP) and phenanthrene were the dominant phthalate and PAH, with median concentrations of 146, 143, and 130 ng/m3 and 1.51, 0.58, and 0.76 ng/m3 in the late spring of 2015, and after retrofits in late spring 2017 and winter of 2017, respectively. SVOC concentrations were generally lower after energy retrofits, with significant differences for phenanthrene, fluoranthene, and pyrene. Lower concentrations post‐retrofit may be related to less overheating and less need for opening windows. Concentrations of phthalates and PAHs in this study were similar to or higher than those reported in the literature. Results suggest that the use of portable air filters is a promising method to assess concentrations of indoor particle‐bound SVOCs. [ABSTRACT FROM AUTHOR]

We applied filter forensics, the analysis of dust from the heating, ventilation, and air‐conditioning (HVAC) filters, to measure particle size distribution in 21 residences in Toronto, Canada over a year. Four filters with different nominal efficiencies (Minimum Efficiency Reporting Value (MERV) 8–14 from ASHRAE Standard 52.2) were deployed in each residence each for three months, while the effective filtration volumes (the product of flow rate, runtime, and in‐situ filter efficiency) were characterized over each filter lifetime. Using extraction and laser diffraction, we found that approximately 90% of the volumetric distributions were >10 µm and the volume median diameter (VMD) ranged from 23.4 to 75.1 µm. Using quantitative filter forensics (QFF), total suspended particle (TSP) concentrations ranged from 2.9 to 823.7 µg/m3 (median = 89.8 µg/m3) with a moderate correlation with the content of TSP on the filters (in terms of g) and with the TSP effective filtration volume (m3) indicating the importance of both filter forensics and HVAC metadata parameters to QFF concentration estimates. There was no strong correlation between PM10 or PM2.5 concentrations and hourly airborne particle number concentrations measured by low‐cost sensors suggesting an evaluation of QFF is warranted, particularly for the exploration of smaller particles. [ABSTRACT FROM AUTHOR]

In this study, we explore different filter and contextual characteristics that influence effectiveness of high‐efficiency filters in 21 residences in Toronto, Canada. The in situ effectiveness was assessed with decay tests at the beginning and the end of filter life with four different filters (MERV 8‐14 from ASHRAE Standard 52.2) installed in operational HVAC systems, compared with either the system off or with no filter installed. There was considerable difference between median PM2.5 effectiveness of the non‐electret filters when compared to electret filters (16% vs. 36%) of the same nominal efficiency (MERV 8). However, median PM2.5 effectiveness of electret filters only slightly improved (between 5% and 9% absolute increase) as MERV increased from 8 to 14. There was more variation in filter effectiveness between the same filter in different homes than there was between different filters in the same home. Variations in filter performance arose because home‐specific particle loss rates (eg, ventilation rate) vary greatly in different buildings. The higher the loss rates due to non‐filter factors, the lower the effectiveness of a filter. Given the relatively large variation in effectiveness for a given filter over time and in different homes, increasing system runtime may be a productive way to improve filter performance in many homes. [ABSTRACT FROM AUTHOR]

• Measured continuous PM and TSP for one-week periods in 91 social housing apartments. • PM concentrations were two to three times higher in smoking apartments. • Non-smoking apartments had PM concentrations twice that of single-family dwellings. • Higher periods of elevated PM suggest that indoor sources are primarily responsible. • Exposure reduction strategies should be employed to improve resident health. Multifamily buildings generally, and social housing specifically, are an important component of most urban environments. Residents of social housing are often exposed to higher concentrations of indoor pollutants. We measured particulate matter (PM) concentrations in 91 smoking and non-smoking apartments across seven social housing buildings in Toronto, Canada before and after energy retrofits. Particle concentrations varied greatly within and between apartments. Of the four environmental factors examined (smoking, season, building, and retrofit status), only smoking (p < 0.001) had a significant effect across all measurements. PM concentrations were two to three times higher in smoking apartments. PM concentrations in non-smoking apartments from this study were two times higher than comparable measurements from 21 single-family homes in Toronto that used the same particle monitor. A source detection algorithm reported elevated PM concentrations during 57% ± 12% of each monitoring period, which was higher than in the single-family homes, suggesting that indoor sources are likely responsible for the concentration differences. Overall, we found that PM concentrations are disproportionately higher in social housing buildings which likely contribute to health disparities and highlight the importance of exposure reduction strategies in this important urban building type. [ABSTRACT FROM AUTHOR]

This study explores the impact of filtration on energy use in residences based on yearlong measurements in 19 homes in Toronto, Canada. Results show that permanent split capacitor (PSC) motor fans drew approximately 40% more power than electronically commutated motor (ECM) fans and the median efficacy (flow divided by power) of ECM fans was 43% higher than that of PSC motor fans. In response to a pressure drop of 150 Pa, ECM fans drew more power (46% − 58% increase) and generally tended to maintain airflow rate, while PSC motor fans drew less power (10% − 23% decrease), but generally tended to reduce airflow rate. Filter pressure drop was not strongly correlated with filter nominal efficiency; thus, the use of higher-efficiency filters may not impact fan power draw. Fan energy consequences of high-efficiency filters are negligible in our sample, and because HVAC runtimes were generally low (median = 11%), the difference between the energy consumption of ECM and PSC motor fans at typical runtimes was small (less than 10 kWh per month). Filters in systems with ECM fans have higher effectiveness per unit of power draw than those in systems with PSC motor fans. [ABSTRACT FROM AUTHOR]