Occupant behavior and indoor particulate concentrations in daycare centers

Chai Yoon Um, Ning Zhang, Kyungmo Kang, Hoo Seung Na, Haneul Choi, Taeyeon Kim

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


‘Occupant behavior’ is the primary mechanism determining indoor particulate concentrations. Various indoor human activities generate particulate matter. Human-building interactions, such as window opening behavior, change the number of outdoor particulate matter introduces to the building. ‘Daycare center’ where young children spend considerable time has an occupant schedule distinguished from other types of buildings. In the study, we analyzed the effects of occupant behavior on indoor particle concentrations in daycare centers by on-site monitoring. The measurements were performed in four daycare centers located in Gyeonggi-do, South Korea. Optical particle counters(OPS, model 3330, TSI Inc., Shoreview, MN, USA) were used for particulate concentration monitoring. The source strengths of particles resuspended by each human activity were calculated, and their contributions to indoor particle concentrations were evaluated. Further, characteristics of human-building interactions and their corresponding impacts on indoor air quality were also analyzed. Results showed that particle resuspension was greater when occupants were awake (mean, 41.0 particles·min−1) than when they were asleep (mean, 9.2 particles·min−1), and the contribution of occupant status was also higher when awake (37–70% vs. 8–18%) for particles sized (0.3–10.0 μm). Analyzing five detailed human activities, vacuuming (9.8·107 particles·min−1) emitted the highest amount of particulate matter per person, followed by physical activity (4.8·107 particles·min−1), sedentary activity (1.9·107 particles· min−1), meals (1.9·107 particles·min−1), and nap time (8.1·106 particles·min−1). The study suggests that vacuuming should be avoided while children are occupied. This research also shows that children could be exposed to high daily average indoor particulate concentration (up to 1217 particles·cm−3) when windows were opened for an extended period of time while poor outdoor air quality. These results indicate that indoor air quality can be severely degraded by opening windows without considering the level of outdoor particle concentration.

Original languageEnglish
Article number153206
JournalScience of the Total Environment
Publication statusPublished - 2022 Jun 10

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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