Exploring the link between ambient PM2.5 concentrations and respiratory diseases in the elderly: a study in the Muang district of Khon Kaen, Thailand.

The impact of air pollution is a major public health concern. However, there are few studies on the correlation between PM2.5 and respiratory infections. This study aimed to determine a link between PM2.5 and respiratory diseases among the elderly in Thailand. The data source for this study consisted of 43 electronic files from the Khon Kaen Provincial Health Office covering years 2020 and 2021 and surveyed a total of 43,534 people. The generalized linear mixed model (GLMM) was used to determine the adjusted odds ratio (AOR), and 95 % CI. We found that exposure to PM2.5 concentrations (in 10 µg m-3 increments) was associated with respiratory diseases (AOR: 3.98; 95 % CI [1.53-10.31]). Respondents who are male, aged less than 80 years, single, self-employed, or working as contractors, have a body mass index (BMI) not equal to the standard, have NCDs (hypertension, diabetes mellitus, and cardiovascular disease), are smokers, live in sub-districts where more than 5 % of the land is planted to sugarcane, or live in close proximity to a biomass power plant were at significantly higher risk of developing respiratory diseases (p<0.05). Therefore, environmental factors including ambient PM2.5 concentrations, the proportion of sugarcane plantation areas, and biomass power plants impact the occurrence of respiratory diseases among the elderly. Also, demographic factors and NCDs are serious issues. Systematic approaches to reducing PM2.5 levels in industrial and agricultural sectors are necessary for both the general population and vulnerable groups, including the elderly and NCD patients.

Drinking water treatment residual as a ballast to sink Microcystis cyanobacteria and inactivate phosphorus in tropical lake water.

The combination of a low dose of coagulant with a ballast that can inactive phosphorus (P) in lake sediment-a technique known as "flock and lock"-is one method for restoration of eutrophic lakes. The effectiveness of a drinking water treatment residual (DWTR) as a ballast in flock and lock was assessed using assays of eutrophic lake water from Thailand dominated by Microcystis aeruginosa cyanobacteria colonies by measuring changes in chlorophyll-a, pH, and zeta potential. P sorption isotherms were developed from long-term batch equilibrium experiments; desorption of nutrients and metals was assessed via leaching experiments; and morphological changes to cellular structure were assessed using scanning electron microscopy. Results showed that combining DWTR with a low dose of aluminum sulfate (0.6-4.0 mg Al/L) effectively sank 74-96% of Microcystis, with DWTR dose (50-400 mg/L), initial chlorophyll-a concentration (92-976 µg/L), pH (7.4-9.3), and alkalinity (99-108 ppm CaCO3) identified as factors significantly associated with sinking efficacy. P sorption capacity of the DWTR (7.12 mg/g) was significantly higher than a local soil (0.33 mg/g), enabling the DWTR to inactivate P in lake sediment. Desorption of Al, Fe, Ca and N from the DWTR was estimated to contribute to a marginal increase in concentrations of those compounds in the water column of a small shallow lake (1.2, 0.66, 53.4, and 0.07 µg/L, respectively) following a simulated application. Therefore, pre-treated DWTRs may be a viable alternative ballast in the flock and lock approach to lake restoration, supplementing or replacing modified local soils or lanthanum modified clays.