Indoor exposure to outdoor particles - Modelling multizone buildings and historical data - Dr Simon Parker
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Indoor exposure to outdoor particles –
Modelling multizone buildings and
historical data
Dr Simon Parker
Chemical and Biological Advice Group, CBR Division
Defence Science and Technology Laboratory
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Background
• Buildings and crowded Image from:
https://image.slidesharecdn.com/nationalsecurityforumpresentationkl
smithv8-120323112143-phpapp02/95/national-security-forum-
spaces are targets for terrorists presentation-by-kimothy-smith-21-728.jpg?cb=1332501970
• Need to understand the impacts of hazardous
airborne materials on indoor environments
to assess risks and protect occupants
– Short term deliberate or accidental releases
– Indoor or outdoor
– Gas or aerosol phase
• Non-residential buildings
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Approaches
• Experiments
– Tracer dispersion
– Scale modelling
– Environmental measurements
• Modelling
– Computational fluid dynamics
– Compartmental models
• Single zone
• Multizone – CONTAM [1] 1. HERRING, SJ, et al. (2016) Providing
Pressure Inputs to Multizone Building
• State-space Models, Building and Environment,
101, 32-44
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
State-space approach
Effect of
ventilation and
• Important assumption losses (constant)
– Steady air flow conditions
Contaminant Source terms
concentrations and external
in zones contaminant
– Reformulation [2] enables
alternative solutions for 2. PARKER, ST, and BOWMAN, V, (2011)
State-space methods for calculating concentration
contaminant transport problems dynamics in multizone buildings.
Building and Environment, 46, 1567-1577.
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Visualising impacts of internal releases [3]
3. PARKER, ST and WILLIAMSON, S (2016) Visual assessment of contaminant impacts in multizone buildings, Building and Environment, 102, 39-53.
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Residential buildings do not necessarily
behave as a single zone for outdoor releases
DH-3 , 7 zones, DH-18, 15 zones, DH-72, 14 zones,
1 floor, no forced air, 3 floors, forced air, 1 floor, forced air,
λbldg = 0.77 h-1 λbldg = 0.35 h-1 garage,
λbldg = 0.29 h-1
maximum S.D.
maximum S.D.
maximum S.D.
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Integral solutions
• In some cases, health effects can be directly related to the
integrated concentration, the exposure, in each building zone
Exposure in each Initial indoor External Internal release
5 min releaseconcentrations
indoor zone duration concentration 60 min release masses
duration
• Limiting exposures are independent of internal release timing [4]
• Internal exposures can be related to external exposures by
including losses due to penetration, deposition and filtration [5]
4. PARKER, ST, COFFEY, CJ, GRAVESEN, J, KIRKPATRICK, J, RATCLIFFE, K, LINGARD, B, NALLY, JP (2014)
Contaminant ingress into multizone buildings - An analytical state-space approach. Building Simulation, 7, 57-71.
5. PARKER, ST, (2013) State-space approach for dilute aerosol modelling in multizone buildings, Aerosol Society Annual Aerosol Science
Conference, University of Hertfordshire, UK.
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Indoor / outdoor exposure AH DH
for 209 multizone buildings [6]
6. PERSILY, A, et al., Technical Report
NISTIR 7330 (2006), NIST
dp = 2 mm
APT MH
Infiltration factor for PM2.5 for US
residential buildings [7]
7. CHEN, C and ZHAO, B, Atmospheric
Environment 45 (2011) 275-288
22 February 2021
© Crown copyright 2013 Dstl
Historical tracer trials
• There are few well-designed and controlled experiments on particle
ingress into buildings
• Aerosol tracer field tests in Minneapolis, USA (Feb 1953) [8-10]
• 61 field tests in 4 areas - residential, river course, flat + open, downtown
• Ingress measurements in different building types / construction materials
• Houses, school, tall office buildings
• Dry powder pigment ZnCdS (NJZ 2266) released
from blower-type generator
• NMD 1.8 µm with 65% of particles between 1 and 3 µm [11]
• ~10 min releases at 1 to 3.5 g·min-1 from vehicles/rooftops 8. http://www.dtic.mil/docs/citations/AD0007261
9. http://www.dtic.mil/docs/citations/AD0031509
• Subsequent review of safety [12] 10. http://www.dtic.mil/docs/citations/AD0031508
11. LEIGHTON, PA, Journal of Applied
• Sample arrays using membrane filters Meteorology, 1965, 4-334
12. The Academy of Medical Sciences,
Zinc Cadmium Sulphide Dispersion Trials, 1999
• Particle counts made under UV illumination and converted to dosage
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600
Results – urban dispersion
e.g. FT0009b
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600Results – Clinton school
Mean IF estimate for
all experiments
IF for each • Indoor versus outdoor
experiment dosages
• Indoor dosages are
estimates as are received
over a longer period
• Multiple locations shown
for both out and in
© Crown copyright 2018 Dstl • Infiltration factor (IF)
estimated =
indoor dosage / outdoor
dosage
• Important for estimating
indoor health effects for
outdoor releases
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600Results – residential buildings
Low wind speeds
House A 0.065 House C 0.138
• 2 storey houses
• Wooden (left) and
stucco (right) structures
• Stucco structures less
leaky – infiltration not
dominated by met so
similar infiltration
House E 0.498 • Differences between House D 0.158
wooden framed houses:
− High winds and low T
for house E: met.
conditions may be
dominating infiltration
− Differences in
structure / circulation
High wind speeds
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600Results - tall buildings
# Building Floors
1 Andrus Building 10
2 First National Bank Building 19
3 Northwestern Bell Telephone Building 26
4 Northwestern National Bank Building 16
5 Baker Building 12
6 Medical Arts Building 10
7 Foshay Tower 32
“1. ANDRUS BUILDING, at 512 Nicollet Avenue, is a commercial, ten-story building of steel
and brick construction. Built in 1900, It has one full floor basement and double-hung,
wood-sash windows. Storm windows are not used, nor is there air conditioning on the upper
floors. Steam heating is supplied from an outside source located in the Plymouth Building.”
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600Indoor Outdoor 22 February 2021 © Crown copyright 2018 Dstl DSTL/CP112600
Conclusions
• Integrated concentrations are particularly useful for exploring
exposures in buildings for short term releases
• Indoor exposures vary within a building for a given outdoor
release
• Historical data can be extremely valuable for gaining additional
insight into outdoor-indoor interactions
• Patterns of dispersion and infiltration vary between tests –
important for future experiments!
• Infiltration factors depend on multiple factors but representative
values are meaningful
22 February 2021
© Crown copyright 2018 Dstl
DSTL/CP112600References
1. HERRING, SJ, BATCHELOR, S, BIERINGER, PE, LINGARD, B, LORENZETTI, DM, PARKER, ST,
RODRIGUEZ, L, SOHN, MD, STEINHOFF, D, WOLSKI, M, (2016) Providing Pressure Inputs to Multizone
Building Models, Building and Environment, 101, 32-44
2. PARKER, ST, and BOWMAN, V, (2011) State-space methods for calculating concentration dynamics in
multizone buildings. Building and Environment, 46, 1567-1577.
3. PARKER, ST and WILLIAMSON, S (2016) Visual assessment of contaminant impacts in multizone
buildings. Building and Environment, 102, 39-53.
4. PARKER, ST, COFFEY, CJ, GRAVESEN, J, KIRKPATRICK, J, RATCLIFFE, K, LINGARD, B, NALLY, JP
(2014) Contaminant ingress into multizone buildings - An analytical state-space approach. Building
Simulation, 7, 57-71.
5. PARKER, ST, (2013) State-space approach for dilute aerosol modelling in multizone buildings, Aerosol
Society Annual Aerosol Science Conference, University of Hertfordshire, UK.
6. PERSILY, A, et al., Technical Report NISTIR 7330 (2006), NIST
7. CHEN, C and ZHAO, B, Atmospheric Environment 45 (2011) 275-288
8. http://www.dtic.mil/docs/citations/AD0007261
9. http://www.dtic.mil/docs/citations/AD0031509
10. http://www.dtic.mil/docs/citations/AD0031508
11. LEIGHTON, PA, Journal of Applied Meteorology, 1965, 4-334
12. The Academy of Medical Sciences, Zinc Cadmium Sulphide Dispersion Trials, 1999
22 February 2021
© Crown copyright 2018 Dstl
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