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

Abstract This study aimed to identify the contributing sources of PM2.5 in Chiang Mai Province during February to April 2016. We therefore investigated the chemical compositions of PM2.5 at two different sites. An urban site is in Chiang Mai University (CMU) while a rural site is in Mae Chaem (MC) District where frequent intensive biomass burning was reported. Thirty pair samples of 24-h PM2.5 were analyzed for organic carbon (OC), elemental carbon (EC), levoglucosan and stable carbon isotope (δ13C). The mean concentrations (Mean ± SD) of PM2.5, OC and EC at the CMU vs MC sites were not significant different (P >0.05) including 44.5 ± 32.1 vs 40.5 ± 21.2 µg/m3; 14.9 ± 12.5 vs 14.8 ± 10.0 µg/m3; and 1.80 ± 1.60 vs 1.62 ± 0.80 µg/m3, respectively. Levoglucosan concentrations, a tracer of biomass burning from both sites were not significant different (P >0.05) and the mean ± SD concentrations at CMU vs MC sites were 0.46 ± 0.56 µg/m3 vs 0.55 ± 0.67 µg/m3, respectively. Meanwhile, the mean values of δ13C in total carbon (TC) at CMU vs MC sites were -27.9 ± 0.68 vs -27.6 ± 0.60‰, respectively which major data (n = 48, 85.4%) fell within the ranged of C3-type plants and minor data (n = 48, 14.6%) in C3-type plants and motor vehicle sources. This finding corresponds to the vast biomass burning area from satellite data. Forest plants in northern Thailand, Chiang Mai particular are mostly mixed deciduous forest i.e. C3-type plants which falling leaves in dry season and easily causing fire. The results of this study therefore strongly suggest that the burning of C3-type forest plants attribute to airborne PM2.5 pollutants in Chiang Mai Province. Keywords: Air pollution, Biomass burning, C3-type plants, Levoglucosan, Stable carbon isotope

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Detection of Beet Sugar Adulteration of Honey

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/69.4.652 ◽

1986 ◽

Vol 69 (4) ◽

pp. 652-654

Author(s):

Jonathan W White ◽

Robert W Meloy ◽

Jerry L Probst ◽

William F Huser

Keyword(s):

Carbon Isotope ◽

Isotope Ratio ◽

Stable Carbon Isotope ◽

Carbon Isotope Ratio ◽

Galactose Oxidase ◽

Stable Carbon ◽

Stable Carbon Isotope Ratio ◽

Beet Sugar ◽

Additional Testing ◽

The Mean

Abstract Quantitation of oligosaccharide-bound galactose by galactose oxidase treatment of the higher sugar fraction is useful to screen honeys with normal stable carbon isotope ratio values for the presence of beet sugar products. For 23 beet sugar products tested, the mean bound galactose value was 30.1 mg/100 g (as galactose); for 81 honeys, the mean was 3.1 mg/100 g, s = 4.4. Nine percent of the honey samples tested had values in the beet sugar range, so additional testing by other procedures is required for confirmation of adulteration, i.e., samples with 8-80 mg/100 g bound galactose should be further tested.

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Are there enormous age-trends in stable carbon isotope ratios of oak tree rings?

The Holocene ◽

10.1177/0959683620941073 ◽

2020 ◽

Vol 30 (11) ◽

pp. 1637-1642

Author(s):

Danny McCarroll ◽

Josie E Duffy ◽

Neil J Loader ◽

Giles HF Young ◽

Darren Davies ◽

...

Keyword(s):

Carbon Isotope ◽

Stable Carbon Isotope ◽

Ring Width ◽

Isotope Ratios ◽

Segment Length ◽

Stable Carbon ◽

Stable Carbon Isotope Ratios ◽

Carbon Isotope Ratios ◽

Age Trends ◽

The Mean

We test a recent prediction that stable carbon isotope ratios from UK oaks will display age-trends of more than 4‰ per century by measuring >5400 carbon isotope ratios from the late-wood alpha-cellulose of individual rings from 18 modern oak trees and 50 building timbers spanning the 9th–21st centuries. After a very short (c.5 years) juvenile phase with slightly elevated values, the number of series that show rising and falling trends is almost equal (33:35) and the average trend is almost zero. These results are based upon measuring and averaging the trends in individual time-series; the ‘mean of the slopes’ approach. We demonstrate that the more conventional ‘slope of the mean’ approach can produce strong but spurious ‘age-trends’ even when the constituent series are flat, with zero slope and zero variance. We conclude that it is safe to compile stable carbon isotope chronologies from UK oaks without de-trending. The isotope chronologies produced in this way are not subject to the ‘segment length curse’, which applies to growth measurements, such as ring width or density, and have the potential to retain very long-term climate signals.

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Consensus δ13C Values

Radiocarbon ◽

10.1017/s0033822200006433 ◽

1984 ◽

Vol 26 (1) ◽

pp. 46-53 ◽

Cited By ~ 22

Author(s):

Richard Burleigh ◽

Keith Matthews ◽

Morven Leese

Keyword(s):

Carbon Isotope ◽

Stable Carbon Isotope ◽

Mean Value ◽

Bone Collagen ◽

Natural Material ◽

Base Line ◽

Stable Carbon ◽

Plant Materials ◽

Animal Bone ◽

The Mean

Selected stable carbon isotope measurements published in Radiocarbon over a 12-year period have been abstracted, plotted, and summarized, to give more reliable estimates of the mean value and range of δ13C for five classes of natural material (human bone collagen, non-human animal bone collagen, plant materials, wood, and charcoal), and to provide a firmer base line for stable carbon isotope dietary and environmental studies.

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