A study of the inhibitory effect and mechanism of airflow regarding mould on building surfaces

Abstract

Air movement dries surfaces by increasing evaporation and convection, which may prevent mould growth. Cladosporium sp. is used as the test organism (dominant fungi in the envelope of rural houses in hot summer and warm winter areas), and the effect of fans on inhibiting mould growth on building materials is investigated. Surface mould growth on materials was simulated and compared after rain leakage and surface condensation, and spore germination was studied in high humidity, with or without airflow. The results are as follows: (1) Airflow has an evident inhibitory effect on mould growth on wet building materials. This observation was linked to the availability of moisture content in the building materials. (2) Airflow can slow the appearance of visual mould on the material surface. Mould did not appear on the gypsum surface due to the airflow, and mould growth on a wood surface was delayed for about two days. (3) Periodically, spore eluates were examined by electron microscopy to determine the stage of spore germination, and it was found that airflow delayed mould spore germination for about 2-3 days.

Keywords

Building envelope / Mould / Airflow / Spores / Building material

References

[1] Arens, E.A. , Baughman, A.V. , 1996. Indoor humidity and human health: Part II - buildings and their systems. ASHRAE Transactions 102 (1), 212- 221.

[2] Brambilla, A. , Sangiorgio, A. , 2020. Mould growth in energy efficient buildings: causes, health implications and strategies to mitigate the risk. Renew. Sustain. Energy Rev. 132, 110093.

[3] Cao, G. , Qian, H. , Li, J. , 2022. Indoor Microbial Pollution and Control in Buildings. China building industry press.

[4] Chen, N. , Shih, C. , Jung, C. , Hsu, Nai-Yun, Chen, C. , Lee, C. , Su, H. , 2022. Impact of mold growth on di(2-ethylhexyl) phthalate emission from moist wallpaper. Heliyon 8 (9), e10404.

[5] Dannemiller, K.C. , Weschler, C.J. , Peccia, J. , 2017. Fungal and bacterial growth in floor dust at elevated relative humidity levels. Indoor Air 27 (2), 354- 363.

[6] Du, C. , Li, B. , Yu, W. , 2021a. Indoor mould exposure: characteristics, influences and corresponding associations with built environment-a review. J. Build. Eng. 35, 101983.

[7] Du, C. , et al., 2021b. Home dampness/mold(D/M) improvement in children’s residences over the past decade in China-a comparison of repeated surveys in 2010 and 2019. Build. Environ. 205, 108181.

[8] Foarde, K. , Cole, E. , Vanosdell, D. , Bush, D. , Franke, D. , Chang, J. , 1992. Characterization of Environmental Chambers for Evaluating Microbial Growth on Building Materials. IAQ, pp. 185-190.

[9] Feng, C. , Janssen, H. , 2021. Impact of water repellent agent concentration on the effect of hydrophobization on building materials. J. Build. Eng. 39, 102284.

[10] Haas, D. , et al., 2014. Comparison of background levels of culturable fungal spore concentrations in indoor and outdoor air in southeastern Austria. Atmos. Environ. 98 (dec.) , 640- 647.

[11] Hanbin, Y. , 2011. Analysis of conditions of temperature and humidity to control microbial contaminant in air-conditioning system. Refrig. Air Cond. 11, 14- 17.

[12] Hansen, T.K. , Bjarlov, S.P. , Peuhkuri, R.H. , Hansen, K.K. , 2018. Performance of hydrophobized historic solid masonry - experimental approach. Construct. Build. Mater. 188 (NOV.10) , 695- 708.

[13] Harding, C.F. , et al., 2020. Mold inhalation causes innate immune activation, neural, cognitive and emotional dysfunction. Brain Behav. Immun. 87, 218- 228.

[14] Johansson, S. , Wadsö, L., Sandin, K. , 2010. Estimation of mould growth levels on rendered façades based on surface relative humidity and surface temperature measurements. Build. Environ. 45 (5), 1153- 1160.

[15] Johansson, P. , Ekstrand-Tobin, A. , Bok, G. , 2014. An innovative test method for evaluating the critical moisture level for mould growth on building materials. Build. Environ. 81, 404- 409.

[16] Kazemian, N. , Pakpour, S. , Milani, A.S. , Klironomos, J. , 2019. Environmental factors influencing fungal growth on gypsum boards and their structural biodeterioration: a university campus case study. PLoS One 14 (8), e220556.

[17] Li, X. , Zhong, Q. , Tang, M. , Gao, Y. , Feng, C. , 2023. Experimental and numerical analysis of the hygric performance of earthen buildings after façade hydrophobization treatment. Case Stud. Constr. Mater., e2217

[18] Madsen, A.M. , 2012. Effects of airflow and changing humidity on the aerosolization of respirable fungal fragments and conidia of botrytis cinerea. Appl. Environ. Microbiol. 78 (11), 3999- 4007.

[19] Mcgill, G. , Moore, J. , Sharpe, T. , Downey, D. , Oyedele, L. , 2015. Airborne bacteria and fungi concentrations in airtight contemporary dwellings. International Congress.

[20] Møller, E.B. , Andersen, B. , Rode, C. , Peuhkuri, R. , 2017. Conditions for mould growth on typical interior surfaces. Energy Proc. 132, 171- 176.

[21] Pasanen, A.L. , Pasanen, P. , Jantunen, M.J. , Kalliokoski, P. , 1991. Significance of air humidity and air velocity for fungal spore release into the air. Atmospheric Environment. Part A. General Topics 25 (2), 459- 462.

[22] Qiu, Y. , et al., 2022. The effects of ventilation, humidity, and temperature on bacterial growth and bacterial genera distribution. Int. J. Environ. Res. Publ. Health 19 (22), 15345.

[23] Qiao, J. , Zhang, X. , Xiao, F. , Li, Y. , Gao, W. , 2024. Experimental investigation of mold growth risk among typical residential indoor materials: case study in coastal city, China. Energy Build. 304, 113885.

[24] Sahlberg, B. , et al., 2013. Airborne molds and bacteria, microbial volatile organic compounds (MVOC), plasticizers and formaldehyde in dwellings in three North European cities in relation to sick building syndrome (SBS). Sci. Total Environ. 444, 433- 440.

[25] Segers, F.J.J. , Van Laarhoven, K.A. , Huinink, H.P. , Adan, O.C.G. , W Sten, H.A.B. , Dijksterhuis, J. , Brakhage, A.A. , 2016. The indoor fungus cladosporium halotolerans survives humidity dynamics markedly better than Aspergillus Niger and Penicillium rubens despite less growth at lowered steady-state water activity. Appl. Environ. Microbiol. 82 (17), 5089- 5098.

[26] Viljoen, M. , Claassen, N. , 2023. Pathophysiological aspects of exposure to dampness-associated indoor mould and mycotoxins: a mini-overview. Journal of Hazardous Materials Advances , 100228.

[27] Wu, H. , Wong, J.W.C. , 2020. The role of oxidative stress in the growth of the indoor mold Cladosporium cladosporioides under water dynamics. Indoor Air 30 (1).

[28] Zoberi, M.H. , 1961. Take-off of mould spores in relation to wind speed and humidity. Ann. Bot.-London 25 (1), 53- 64.

[29] Zhai, Y. , Zhang, H. , Zhang, Y. , Pasut, W. , Arens, E. , Meng, Q. , 2013. Comfort under personally controlled air movement in warm and humid environments. Build. Environ. 65, 109- 117.

RIGHTS & PERMISSIONS

2024 The Author(s). Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.