Modeling of the aerosol infiltration characteristics in a cultural heritage building: The Baroque Library Hall in Prague

Abstract

Please cite this article as: Chatoutsidou SE, Mašková L, Ondráčková L, Ondráček J, Lazaridis M, Smolík J, Modeling of the aerosol infiltration characteristics in a cultural heritage building: The Baroque Library Hall in Prague, Building and Environment (2015), doi: 10.1016/j.buildenv.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A dynamic mass balance model was introduced taking account particle penetration from outdoors and indoor losses (deposition, ventilation). The model was used to determine deposition rate k and penetration efficiency P in 13 discrete size intervals. Model performance was evaluated using the coefficient of determination (R 2 ) by selecting different pairs of k and P. No unique solution found, thus, averaged values of k and P from the best correlated pairs were used to estimate infiltration factor. Good agreement between infiltration factor and I/O ratio confirmed that modeled k and P were well-estimated. The deposition rate was found to depend strongly on particle size with higher rates for ultrafine and coarse particles. Penetration efficiency, on the other hand, was not clearly related with particle size. The infiltration factor varied substantially with particle size with less effective removal for accumulation fraction (0.1-0.7 µm). Higher infiltration factor for ultrafine particles, compared to coarse particles, indicates that enrichment of the library at this size is caused by penetration from outdoors. On the other hand, human presence during visiting hours found to contribute significantly to coarse particles by increasing the indoor number concentration by a factor of 3, 3.2 and 2 during spring, summer and winter respectively.

Contribution of Visitors to the Indoor PM in the National Library in Prague, Czech Republic

“…The average value a = 0.13 h -1 was stable with the relative standard deviation (RSD) approximately 14%. The same average value was found in spring campaign in 2009 (Chatoutsidou et al, 2015).…”

“…Temporal variation of size resolved indoor and outdoor PM showed that main source of indoor coarse PM are visitors and fine PM infiltration from the outdoor environment (Chatoutsidou et al, 2015). Similar effect has been already described in several studies related to indoor air quality in museums (e.g., Camuffo et al, 1999;Worobiec et al, 2008;Wang et al, 2015;Xiu et al, 2015).…”

“…Sampling site has already been described in previous studies (Andělová et al, 2010;López-Aparicio et al, 2011;Chatoutsidou et al, 2015) and so only details related to this study are mentioned. PM concentrations were measured in an old BLH of the National Library (Clementinum historical complex) located in the Old Town of Prague in the city centre.…”

“…However, there were very low concentrations for particles larger than about 2.5 µm resulting in insufficient counts to provide adequate count statistic and therefore these data were excluded. The values of k i as a function of particle size found from the fit are compared with results for four sizes fractions found from the best fit between the measured indoor concentrations and the obtained modelled indoor concentrations (Chatoutsidou et al, 2015) in Fig. 4.…”

“…The assumption of ideal mixing was verified by multi-compartment modelling (Takkunen et al, 2011). The time and size resolved PM number concentration data were also used to estimate particle penetration factor P and deposition rate k. The estimation was based on comparison of measured and modelled data, however no unique solution was found (Chatoutsidou et al, 2015). This is probably due to a nearly linear inverse relationship between particle penetration and deposition that occur simultaneously (Bennet and Koutrakis, 2006).…”