In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 18, No. 19 ( 2018-10-01), p. 13865-13879
Abstract:
Abstract. Arsenic (As) has long been recognized as a toxic element of
mainly anthropogenic origins, having adverse effects on human health.
However, there is insufficient understanding regarding As released into
atmosphere from biomass burning (BB). To this end, daily airborne As
concentrations in total particulate matter (TSP) were determined at Mount
Hehuan (24.16∘ N, 121.29∘ E, 3001 m a.s.l.), Taiwan from
September 2011 to September 2012. During the sampling period, As
concentrations varied from 0.02 to 5.9 ng m−3, with a mean value of 0.5±1.0 ng m−3. Significantly seasonal variations of As were found
over the subtropical free troposphere, and higher As concentrations were
observed in the southern (S) and southeastern (SE) Asian BB seasons (from January
to May). Principal component analysis (PCA) results showed that BB activities
seemed to be a major source of As during the S and SE Asian BB periods,
which were very distinct from the major source of coal-fired power plant during the
periods between July and December. Based on backward trajectory analyses and
WRF-Chem model simulations, we found that the high As concentrations during the BB
periods were attributed to the biomass burning activities over S Asia where
groundwater, soil and crops are severely contaminated by arsenic. A strong
correlation (r=0.73 p〈0.05) between As and potassium ion
(K+, a chemical tracer of BB activities) in S Asian BB events also
supported this hypothesis. During the S Asian BB events, the high As ∕ Pb
ratios (〉0.2) were also observed, indicating that burning crops
contaminated by lead arsenate might be a crucial candidate for high As
concentrations at Mount Hehuan. Nevertheless, the net influence of S Asian BB
activities on airborne As concentrations has been estimated by comparing the
differences of As concentrations on BB and non-BB days. On average, the
difference in As concentrations was 1.0 ng m−3, which accounted for 63 %
of the average As concentration on BB days. Moreover, a ratio of ΔAs∕ΔCO (∼0.00001) in the S Asian BB events was
obtained. Using this value, arsenic emissions from S Asian BB activities were
estimated to be 0.17 tons yr−1, resulting in high airborne As
concentrations over the subtropical free troposphere and impacting As cycles
on a regional scale in the S and SE Asian BB seasons.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-18-13865-2018
DOI:
10.5194/acp-18-13865-2018-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
Permalink