Post on 27-Dec-2015
Dr Nigel Blades
UCL Centre for Sustainable Heritage
UCL CENTRE FOR SUSTAINABLE HERITAGE
Application of an Air Pollution Modelling Tool to Cultural Heritage Buildings
IMPACT pollution model - JAVA applet implementation of pollution mass balance
equation of Weschler et al. (1989)
• Model outputs:– Indoor pollutant concentration or
I/O ratio – Which surfaces absorb most
pollutant– Relation between I/O ratio and
ventilation rate
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Case study 1: Sainsbury Centre for Visual Arts, Norwich, UK
• Metal walls and ceiling• Glass end walls• Open plan display area• Mechanical ventilation but
not air conditioning• Close relation to outdoor
environment
Sainsbury Centre for Visual Arts
Table 1: Data on the SCVA used in the modelling
Internal surfaces Aream2
Other parameters
Metallic wall finish 2620 Room volume 42570 m3
Metallic ceiling finish 4585 Air change rate 1.5ach
Glass 528 Temperature 20°C
Carpeted floor 4257 Relative humidity 55%
Inner wall insulation 2064
IMPACT modelling of the SCVA
Model scenario Sulphur dioxide
Nitrogen dioxide
Ozone
(a) SCVA without interventions 0.89 0.87 0.88
How can pollution control be improved at the SCVA?
IMPACT modelling of the SCVA
Model scenario Sulphur dioxide
Nitrogen dioxide
Ozone
(a) SCVA without interventions 0.89 0.87 0.88
(b) Reduce ventilation rate to 0.3ach 0.76 0.78 0.78
(c) Introduce enhanced pollution absorbing paint
0.72 0.70 0.72
(b) and (c) combined 0.62 0.62 0.62
Case study 2: Factory building converted into an archive store
• Concrete walls and floors• Most glazing covered over• Naturally ventilated, but
building tightly sealedDoor to outside
Entrance lobby
Internal doors
Stair well
modelled zone
Data used to model the archive store
Surface Area m2
Other parameters
Concrete wall 582 Room volume 7972m3
Chipboard window covers 214 Air change rate 0.3 ach
Synthetic flooring 1355 Temperature 20°C
Concrete ceiling 1355 Relative humidity 55%
Exposed paper and book boards 6934
IMPACT modelling of nitrogen dioxide at the archive store
IMPACT modelling of the archive store – results for all gases
Pollutant Modelled I/O ratio
Nitrogen dioxide 0.46
Ozone 0.24
Sulphur dioxide 0.33
IMPACT modelling of the archive store – results for all gases
Pollutant Modelled I/O ratio
Nitrogen dioxide 0.46
Ozone 0.24
Sulphur dioxide 0.33
Is this good for conservation of the collection?
IMPACT modelling of the archive store – pollution effects on the collection
Pollutant Modelled I/O ratio(with collection)
Modelled I/O ratio(no collection)
Nitrogen dioxide 0.46 0.78
Ozone 0.24 0.73
Sulphur dioxide 0.33 0.60
IMPACT modelling of the archive store – comparison with measured data
Pollutant Modelled I/O ratio Measured I/O ratio
Nitrogen dioxide 0.46 0.24
Ozone 0.24 0.1
Sulphur dioxide 0.33 0.4
Reasons for discrepancy between measured and modelled data
• Amount of active surface area in the building has been underestimated
• Single zone model does not allow for air infiltration from other zones (rooms)
• Enhanced pollution deposition around cracks and crevices where air infiltrates
• Homogeneous chemistry?
Conclusions
• IMPACT model can quickly and easily estimate the contribution of outdoor pollution to indoor environment, using a simple deposition model
• Help understand relation between air pollution and buildings
• Teaching aid for conservators in UK and Malta, COST G8 Training School
• In use by heritage organisations, e.g. English Heritage
European project details
IMPACT, Contract No. EVK4-CT-2000-00031, ‘Innovative Modelling of Museum Pollution and Conservation Thresholds’ (2000-04)
http://www.ucl.ac.uk/sustainableheritage/impact