Changes in PM 2.5 peat combustion source profiles with atmospheric aging in an oxidation flow reactor

• Published in: Atmospheric Measurement Techniques
• Main Authors: J. C. Chow, J. Cao, L.-W. Antony Chen, X. Wang, Q. Wang, J. Tian, S. S. H. Ho, A. C. Watts, T. B. Carlson, S. D. Kohl, J. G. Watson
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2019
• Subjects: Environmental engineering; TA170-171; Earthwork. Foundations; TA715-787; Alaska; Siberia
• Online Access: https://doi.org/10.5194/amt-12-5475-2019; https://doaj.org/article/7b51b366d2be4326a6a316b2144a4b66

Smoke from laboratory chamber burning of peat fuels from Russia, Siberia, the USA (Alaska and Florida), and Malaysia representing boreal, temperate, subtropical, and tropical regions was sampled before and after passing through a potential-aerosol-mass oxidation flow reactor (PAM-OFR) to simulate intermediately aged ( ∼2 d) and well-aged ( ∼7 d) source profiles. Species abundances in PM 2.5 between aged and fresh profiles varied by several orders of magnitude with two distinguishable clusters, centered around 0.1 % for reactive and ionic species and centered around 10 % for carbon. Organic carbon (OC) accounted for 58 %–85 % of PM 2.5 mass in fresh profiles with low elemental carbon (EC) abundances (0.67 %–4.4 %). OC abundances decreased by 20 %–33 % for well-aged profiles, with reductions of 3 %–14 % for the volatile OC fractions (e.g., OC1 and OC2, thermally evolved at 140 and 280 ∘ C). Ratios of organic matter (OM) to OC abundances increased by 12 %–19 % from intermediately aged to well-aged smoke. Ratios of ammonia (NH 3 ) to PM 2.5 decreased after intermediate aging. Well-aged <math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="9641cdd414b305565815b5b604dabf23"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-5475-2019-ie00001.svg" width="24pt" height="15pt" src="amt-12-5475-2019-ie00001.png"/></svg:svg> and <math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn ...