Environmental context. Airborne particulate matter (PM) is a major public health risk in Southeast Asia. The annual average concentration of fine PM (PM_2.5) in the region is significantly higher than the WHO air quality guidelines, and higher PM_2.5 levels were recorded during dry seasons, primarily due to biomass burning. In this paper, we provide an overview of the seasonal variations in concentrations, chemical compositions, and sources of PM in Southeast Asian countries.

Environmental context. Photocatalytic TiO₂ materials are good prospects in water quality treatment due to their stable chemical properties and limited secondary pollution. TiO₂ photocatalytic material prepared with biochar as a carrier can greatly improve the photocatalytic efficiency of Cr^VI, and the removal rate of Cr^VI can reach 84.4%. This study shows that biochar-supported TiO₂ photocatalytic composites are feasible for the green and efficient removal of Cr^VI from an aqueous phase.

Environmental context. Pharmaceuticals find their way to wastewater mainly through hospital and industrial effluents, and in turn affect all living organisms. The routine analysis of different water sources is tedious and of high cost. Our work presents a safe, low-cost method for analysing water samples to ensure proper cleanup of water and its suitability for human and animal use.