No abstract

Biomass burning contributes to various organic substances in the atmosphere. Levoglucosan has been recognised as one of the indicators of biomass burning and surfactants are a group of molecules which can be distributed through biomass burning. This research aims to determine the composition of levoglucosan and surfactants in agricultural areas and the several tropical plant species which can contribute to a high amount of levoglucosan and surfactants in the atmosphere. Suspended particulate matter in the atmosphere (fine and coarse mode) was collected in the agricultural areas (paddy fields) during the dry season and compared to samples collected at the Universiti Kebangsaan Malaysia (UKM), Bangi. The soot samples were prepared through the burning of several tropical plant species, namely: Oryza sativa, Rhizophora spp., Elaeis guineensis and Saccharum officinarum at 300°C in a furnace. This allowed for the levels of levoglucosan and surfactants such as MBAS and DBAS to be determined using the colorimetric method. Oxidation and UV radiation were also used to examine the impact of photo-oxidation on the concentration of levoglucosan and surfactants in soot. The results showed that the concentration of levoglucosan in the agricultural areas during harvesting season is significantly higher compared to the levoglucosan recorded at UKM Bangi (semi-urban areas). The concentration of surfactants is dominated by anionic surfactants, particularly in fine mode aerosols. Soot from leaves was found to contribute a high amount of levoglucosan when compared to wood and straw. There are indications that biomass burning can contribute to a large quantity of polar group molecules which behave like anionic surfactants and correlate to the amount of surfactants.

RESUMENSe midieron concentraciones de PM 10 tanto en interiores como exteriores en 10 edificios residenciales de Phitsanulok, Tailandia, durante las temporadas de seca y lluvias de 2014. Además, se analizaron siete metales traza en el PM 10 : Zn, Fe, Pb, Cd, Ni, Cu y Cr. Las concentraciones mensuales intra y extramuros de PM 10 fueron de 41.5 a 105.3 µg m -3 y de 95.2 a 145.1 µg m -3 , respectivamente. Las concentraciones de PM 10 fueron significativamente mayores durante la temporada seca, en comparación con la temporada húmeda. Las razones interior/exterior fueron menores a uno, lo cual indica que el material particulado se origina en ambientes exteriores. En general, las concentraciones medias de metales pesados en el PM 10 variaron de 0.2 a 2.7 y de 0.5 a 7.1 µg m -3 para el ambiente interior y el exterior, respectivamente. En el PM 10 de interiores se encontró una fuerte correlación positiva entre Zn y Cu, Zn y Ni, y Cu y Ni. Asimismo, se encontró una fuerte correlación entre Zn y Ni, Pb y Cu, Cu y Ni, Cd y Ni, y Zn y Cu en exteriores. Los factores de enriquecimiento de Zn, Cu, Pb, Cr y Ni fueron menores a uno, lo cual sugiere que los metales en el PM 10 de interiores se originaron en materiales de la corteza. En cuanto a la valoración de riesgos sanitarios, se determinó mediante una evaluación de riesgos con un sistema integrado de información, que el Cr implica el mayor riesgo de cáncer. ABSTRACTThe concentrations of PM 10 were measured both indoors and outdoors at 10 roadside residential buildings in Phitsanulok, Thailand during the dry and wet seasons of 2014. Seven trace metals (Zn, Fe, Pb, Cd, Ni, Cu and Cr) were also analysed in PM 10 . The monthly average concentrations of indoor and outdoor PM 10 were 41.5 to 105.3 µg m -3 and 95.2 to 145.1 µg m -3 , respectively. PM 10 concentrations were significantly higher during the dry season compared to the wet season. The indoor/outdoor (I/O) ratios were less than one indicating that the particulate matter originates from the outdoor environment. Overall, the average concentrations of heavy metals in PM 10 ranged from 0.2 to 2.7 µg m -3 and 0.5 to 7.1 µg m -3 for the indoor and outdoor environments, respectively. A strong positive correlation in indoor PM 10 was found between Zn and Cu, Zn and Ni, and Cu and Ni. Zn and Ni, Pb and Cu, Cu and Ni, Cd and Ni, and Zn and Cu showed strong positive correlations in the outdoor environment. The enrichment factors of Zn, Cu, Pb, Cr and Ni were less than one suggesting that the metals in indoor PM 10 have originated from crustal materials. For the health risk assessment, Cr was found to have the highest excess cancer risk in an evaluation using an Integrated Risk Information System.

No abstract

Seasonal variability of daily particle mass and saccharides and furfural concentrations in atmospheric particulate matter in both coarse aerosols (diameter > 2.4 µm) and fine aerosols (diameter < 2.4 µm) was determined for a semi-urban area in the United Kingdom. Saccharides, which include levoglucosan, and furfural are derived from biomass burning and contribute to aerosol composition. This study examined the potential of saccharides and furfural as tracers for biomass combustion. High saccharide concentrations were observed in the autumn, but they did not show a high correlation with potassium expected in biomass smoke. These results may imply that the high saccharide concentrations are derived not only from biomass burning sources, but also from non-combustion sources, such as leaf decay. Significant seasonal variations were observed for saccharides and furfural species in fine atmospheric aerosols. Furfural is likely to be oxidized quickly in comparison with saccharides, so while saccharides such as levoglucosan are known to be fairly stable in the atmosphere, furfural could be transformed. Trajectory and factor analysis suggest that the saccharides may result from long-range transport, while furfural may be more influenced by the local sources possibly because of its shorter lifetime. This result may suggest it could give clues as to the age of biomass smoke.