Exploring the Sources of PM10 Burning-Season Haze in Northern Thailand Using Nuclear Analytical Techniques

Abstract

This study explored the sources of PM 10 in the smoke haze during the traditional burning season in northern Thailand by determining the characteristics of the atomic elements in PM 10 compared to known plant samples. The ambient air was collected from two sites (urban and peri-urban) in the Chiang MaiLamphun Basin. This was compared to the characteristics of the leaves from eight agricultural and forest plants predominant in the region: bamboo, grass, teak, yangna, corn, longan, lychee, and rice that were collected and burned in a combustion chamber to collect the resultant PM 10 . The elements -Al, Si, S, Cl, K, Ca, Ti, Cr, Mn, and Fe -were analyzed by PIXE, SEM-EDS, and μ-SXRF. Morphologies of PM 10 particles were analyzed by SEM. The concentrations of the elements in the PM 10 of the ambient air samples correlated highly with the PM 10 from the combustion of teak, yangna, and corn leaves. The results of principal component analysis (PCA), correlations, and morphological characteristics analyzed by SEM also showed that the ambient air PM 10 belonged to the same group as the PM 10 from combustion of teak, yangna, and corn. A HYSPLIT trajectory model indicated that the ambient air PM 10 in the Chiang Mai -Lamphun Basin was derived primarily from hotspots on the Thai-Myanmar border driven by southwest winds, as well as some hotspots in the basin itself. This study has shown that open burning of plant sources, both forest and agricultural, particularly along the Thai-Myanmar border to the southwest, is a primary source of the smoke haze in the Chiang Mai -Lamphun Basin during the dry season.

Significant Contribution of C3 - Type Forest Plants’ Burning to Airborne PM2.5 Pollutions in Chiang Mai Province, Northern Thailand

“…The major direction of the air masses at both sites passed through southern Myanmar and the parts of Mae Hong Son. In this region, there was high distribution of fire hotspots during the study period as also shown in previously reports (Khamkaew et al, 2016;Kiatwattanacharoen et al, 2017;Punsompong and Chantara, 2019).…”

“…Khamkaew et al, (2016) reported that the mean PM2.5 concentrations collected at Chiang Mai University (CMU) between March and April 2014 were largely attributed to local open burning of agricultural matter and forest fires (Khamkaew et al, 2016). Air pollution in Chiang Mai City studied in the dry season of 2010 suggested that open burning of plants was the predominant contributor to air pollution in this area and was found to be highly correlated with element concentrations in ambient PM10 (particulate matter with an aerodynamic diameter less than 10 µm) and the combustion of teak, yangna, and corn stalks (Kiatwattanacharoen et al, 2017). Mae Chaem (MC) is a rural district in Chiang Mai Province and the terrain consists of mostly foothills and mountain ridges surrounding a small basin approximately 350 m above mean sea level.…”

Modeling the effect of VOCs from biomass burning emissions on ozone pollution in upper Southeast Asia

“…It makes substantial contributions of 29% and 16% of O 3 and CO, respectively, during the high-emission period in March compared to those in the low-emission period in December. As much as 70% of biomass burning in this region occurs in Myanmar and Laos, as reported by Punsompong and Chantara (2018) and Kiatwattanacharoen et al. (2017).…”

How Harmful Is Particulate Matter Emitted from Biomass Burning? A Thailand Perspective

“…To better understand whether specific types of biomass have differential toxicity, PM samples could also be generated in the laboratory, by burning biomass samples that are relevant to Thailand (e.g. Bambusa vulgaris, Echinochloa crus-galli, Tectona grandis, Diptero carpusalatus, Zea mays, Oryza sativa, Dimocarpus longan, and Litchi chinensis [120]) and testing the toxicity of the emitted PM in vitro and in vivo.…”