Healthy Buildings 2021 Europe

1. Humanpersonalcloudassociatedwith
particlesandgasesin anofficestudy:
Preliminaryresults
Shen YANG (Presenter), Dusan LICINA*
Human-Oriented Built Environment Lab (HOBEL)
School of Architecture, Civil and Environmental Engineering
École Polytechnique Fédérale de Lausanne (EPFL), Switzerland
shen.yang@epfl.ch
dusan.licina@epfl.ch

2. « Personalcloud »
An excess [difference] of
air pollutant concentration
in peri-human environment
relative to room-average
levels
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YANG
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“Pig-Pen” effect:
“… attracts a permanent cloud
of dust and bugs.”
[Source: peanuts.com]

3. Howpersonalcloudcomes
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▪ Well-mixed room air — ideal
▪ Non-uniform distribution — realistic
▪ Origination
Human emissions
Breath
Skin & clothing
Chemical reaction
Other sources
Human activities
Proximate sources
Endogenous
Exogenous
Douaa et al., Indoor Air, 2021

4. Why personalcloudmatters
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▪ Exposure
Outdoor Indoor Personal
Atmospheric pollution
vs.
Morbidity & mortality
Indoor pollution
vs.
Exposure evaluation
Well-mixed assumption
Personal cloud
vs.
Refined exposure evaluation
Spatial distribution

5. Theaimofthisstudy
While precedent research
focused on chamber
experiments, this study
performed a field measurement
of human personal cloud
associated with particles and
gases in an office
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• To see the magnitude of
personal cloud of several air
pollutants in a naturally
ventilated office environment
• To measure personal exposure
in the office and to tell how
much the personal cloud effect
matters
PM10
VOCs
CO2
Licina et al., Indoor Air, 2017
Pantelic et al., JESEE, 2020

6. Experimental
Design
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Particles: Grimm MiniWRAS & MetOne 804
VOCs: TOXpro VOC & Aldehyde passive badges
CO2: HOBO MX1102 CO2 logger
Occupancy logger
Activity diary
3 Personal sites
Standard office work
without manipulation
4 Room stationary sites
The difference: Personal cloud

7. IndoorVOCsand personalcloud
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Name Room average P1 P2 P3
Ethyl Alcohol 1378.7 1598.8 2312.0 2404.4
Acetone 26.0 35.2 41.2 46.2
Isopropyl Alcohol 112.9 133.7 197.7 289.8
Cyclopentane 3.8 0.0 0.0 7.7
1-Butyl alcohol 15.7 18.5 0.0 0.0
Toluene 7.6 8.1 7.1 8.6
Alpha-Pinene 58.0 62.9 53.6 72.2
Formaldehyde 58.4 73.5 65.7 84.2
Acetaldehyde 18.7 25.1 26.2 28.4
Propionaldehyde 1.5 4.6 6.0 6.5
Butyraldehyde 0.0 3.0 4.0 10.6
Benzaldehyde 0.0 6.1 11.2 0.0
Glutaraldehyde 0.0 0.0 0.0 0.0
Total(As Toluene) 230.6 265.3 358.5 422.1
Significant higher than room average (+3STD)
Sanitizer
Exhalation
Exceeding: 9 μg/m3
Exceeding: 200 μg/m3
VOC personal cloud does exist in typical office environments, varying 0-1000 μg/m3,
dependent on chemicals and occupants

8. CO2 personalcloud
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CO2 personal cloud does exist in typical office environments, varying 0-500 ppm,
dependent on occupants

9. PM10 personalcloud
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PM10 personal cloud does exist in typical office environments, varying 0-6 μg/m3,
dependent on occupants

10. Conclusion
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• A difference in air pollutant concentrations
between personal and room site was observed
in an office environment, implying potential bias
in studies estimating inhalation exposures.
• The preliminary results have shown that the
personal cloud magnitude of CO2, VOCs and
total particles can range within 0-500 ppm, 0-
1000 μg/m3, and 0-6 μg/m3, respectively.
• The results are valuable for refined
characterization and enhanced control of
personal exposure to air pollutants.