This study characterized the particulate matter (PM) pollution at a forest site in the Khao Yai (KY) National Park of Thailand, 700 m above sea level and 120 km upwind to Bangkok during the dry season. Two dichotomous samplers simultaneously operated on each monitoring day to collect 2 samples (on 2 filter types: quartz and mix cellulose) of 24 h PM 2.5 and 2 samples of 24 h PM 10-2.5 . More focus was on the dry and more polluted season with a longer sampling period (43 days: Jan-Feb 2005) and less on wet season (10 days, Jun 2005). Samples were analyzed for mass, water soluble ions, elements, EC and OC (Sunset analyzer). PM 2.5 levels obtained at KY in the dry period (47 µg m -3 ) were comparable to those in several urban areas in Southeast Asia, but the wet season levels (7 µg m -3 ) were significantly lower. In the dry season, levels of EC associated with PM 2.5 at KY were remarkably lower than but OC were comparable to those found in urban areas which resulted in considerably low EC/TC ratios (0.08). The major mass groups of PM 2.5 in the dry season were organic matter of biomass smoke origin (OM-smoke), secondary inorganic aerosol, organic matter of other origins than smoke (OM-others) and crustal. Similar contributors to PM 2.5 were also found in the wet season but with only a small contribution from biomass burning smoke. Significant contributions from distant sources to PM 2.5 levels measured at KY were also confirmed by the HYSPLIT backward trajectory analysis. The coarse fraction (PM 10-2.5 ) had major mass groups of OM-others, inorganic particles and crustal that were most likely related to local sources, and some amount of aged sea salt indicating a distant source origin.
Historical buildings are recognized as the valuable cultural heritage of a nation. They may suffer material deterioration unavoidably because of exposure to air pollution. We used geographic information systems with dose-response functions (DRFs) to estimate the corrosion of copper and Portland limestone, and their risk of corrosion with regard to historical buildings in Bangkok, Thailand. The first step was to find a suitable spatial interpolation method considering the air pollution and meteorological measurement data for 2010-2019 from 26 monitoring stations in Bangkok and its neighborhoods. Applying multiple performance measures, the inverse distance weighting (IDW) method was found to be the most suitable. Predictions of the pollutant concentration in the spatial atmosphere showed that the concentration of all pollutants (SO2, NO2, O3, and PM10) tends to increase in 2028. Air pollution exposure time duration tends to be a key factor affecting the corrosion of material. The results of spatial corrosion estimations indicated that in 2010, the corrosion of copper and Portland limestone were at acceptable levels; however, the estimated corrosion levels for 2019 and 2028 are higher and beyond the acceptable levels. Moreover, both materials in the Rattanakosin historical area exceed their tolerable corrosion rates with considerably serious risks in 2028. The results can be further used to establish active measures to reduce the rate of corrosion of historical buildings in Bangkok.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.