Northern Thailand has long been severely affected by haze from biomass burning containing fine and ultrafine aerosols in the dry period. The carbonaceous PM0.1 comprising elemental carbon (EC) and organic carbon (OC) collected during the haze and non-haze periods in Chiang Mai, Thailand was investigated. The PM0.1 levels during the haze periods were about 3 times higher than the non-haze periods, a significant increase. PM0.1 concentration was strongly correlated with atmospheric relative humidity and the number of forest fire hotspots. Carbonaceous aerosol characteristics in PM0.1 were analyzed with the thermal/optical transmittance (TOT) method

Oil palm (Elaeis guineensis) trees are an important contributor of recent economic development in Southeast Asia. The high product yield, and the consequent high profitability, has led to a widespread expansion of plantations in the greater region. However, oil palms are susceptible to diseases that can have a detrimental effect. In this study we use hyper- and multi-spectral remote sensing to detect diseased oil palm trees in Krabi province, Thailand. Proximate spectroscopic measurements were used to identify and discern differences in leaf spectral radiance; the results indicate a relatively higher radiance in visible and near-infrared for the healthy leaves in comparison to the diseased. From a total of 113 samples for which the geolocation and the hyperspectral radiance were recorded, 59 and 54 samples were healthy and diseased oil palm trees, respectively. Moreover, a WorldView-2 satellite image was used to investigate the usability of traditional vegetation indices and subsequently detecting diseased oil palm trees. The results show that the overall maximum likelihood classification accuracy is 85.98%, the Kappa coefficient 0.71 and the producer’s accuracy for healthy and diseased oil palm trees 83.33 and 78.95, respectively. We conclude that high spatial and spectral resolutions can play a vital role in monitoring diseases in oil palm plantations.

Rapid economic growth has led to increasing air pollution in Southeast Asia (SEA). Urbanization, industrialization and open biomass burning all lead to deteriorating air quality. Recent advances allow recording, sampling and analyzing ultrafine particles, or nanoparticles, finer than the already extensively reported PM2.5 particles; these nanoparticles have been shown to be a potentially more significant health hazard – causing cardiovascular and respiratory diseases, since they can penetrate further into our bodies. Analysis of the collected particles allows, in turn, identifying sources. Although vehicle emissions generally dominate nanoparticles, biomass generates a significant proportion in the burning seasons. In Malaysia, the number of particles smaller than 50 nm dominate, but, by mass, PM0.1 accounts for ∼15% of PM2.5 in upper SEA, and ∼18% in lower SEA. Sampling compared normal periods, where ratios of organic to elemental carbon and char to soot elemental carbon indicated that vehicle exhaust dominates. However, in haze periods, increased char to soot elemental carbon ratios indicate strong contributions from biomass burning. In lower SEA severe haze periods, polycyclic aromatic hydrocarbon levels are 3–8 times higher than in normal periods, confirming the sources as peatland fires in Indonesia. Open biomass burning clearly contributes a significant portion of PM0.1 during SEA haze periods. Further PM0.1 studies are needed to better understand sources, transport and influences on human health to identify suitable measures to solve the problem sustainably.

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