The characteristics, and soiling defects of airborne particulates towards inorganic-based artefacts inside the National Museum of Malaysia

Abstract

Artefacts are continuously exposed to adverse climatological conditions such as the high concentration of Particulate Matter, unstable Temperature and Relative Humidity. These adverse climatological conditions can cause varieties of mechanical, chemical and biological damages to the exhibits in a museum and cultural heritage building collections. As such, this research is aimed at determining the rate of soiling in order to reduce the hazardous effect caused by climatological conditions on artefacts in Gallery A and Gallery B of the National Museum, Kuala Lumpur, Malaysia. The researchers collected data for 40 days. The mass concentration of PM in terms of Respirable and Total Inhalable particles were obtained at various sample stations using Cyclone sampler heads and 7-Holes head, respectively. Average mass concentration results were subsequently analysed by comparing the weekdays and weekends results and with the Department of Safety and Health (DOSH) guideline stated in the industrial code of practice on Indoor Air Quality 2010 edition, and Department of Environment (DOE) guidelines on Ambient Air Quality (Iterim-2018). HOBO data loggers were placed at respective sample stations to determine the state of the microclimate conditions, and the possible effects on the exhibits in Gallery A and Gallery B. The obtained microclimate parameters at various stations were further evaluated by comparing with required fluctuation limits stipulated in the 2015 ASHRAE Handbook and Italian Standards (UNI 10829/99). Relationship between average 8 hours microclimate parameters and mass concentrations values were computed using the Pearson Correlation and Multiple Linear Regression methods. Furthermore, the elemental composition of short-term dust-fall sample were collected on artefacts at the various sampling station. The average mass concentration results at most of the sample stations were more than the required standard set by DOE and DOSH, with the highest value of 0.4688 mg/m3 obtained at the metal and ceramic showcase at weekdays, a result 213 times above the required standard. The result of respirable dust to the total inhalable dust were 55.4 % and 59.7 % for weekdays and weekends, respectively. The microclimate results show that there is an unwanted variability in most of the sample stations during the period of this research in both Galleries. The variation can cause several damages to artefacts present in both Galleries. The temperature measured in the Museum was between 20°C and 30.5 °C and relative humidity varied from 50% and 71%, in both Galleries. Most of the temperatures and relative humidity results in Gallery A and Gallery B were also found to be beyond the acceptable fluctuation limits set by ASHRAE and the UNI 10829/99 standards. The result of correlation and regression indicates that the hygrothermal microclimate of the indoor area of Gallery A and Gallery B has a significant effect on the mass concentration of dust particulates, with Gallery A being significantly affected. A total of fourteen (14) elements (Al, Cr, Fe, Cu, Zn, Pb, Bi, Ti, Co, Ni, Si, V, Mn, and Mg) were observed, most of which are detrimental to artefacts present in the museum and mostly originates from a man-made source. The elements dominating Gallery A and B are Zn, Cr, Al, and Fe, with percentage elemental composition of 15.95 %, 9.64 %, 7.56 % and 6.55 %, respectively. Therefore, it can be concluded that the climatological conditions of Gallery A and Gallery B of the National Museum Malaysia are above required standard and urgent attention needs to be arranged to reduce the damages it can cause.