In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 19, No. 4 ( 2019-03-01), p. 2701-2712
Kurzfassung:
Abstract. Atmospheric particulate water is ubiquitous, affecting particle transport and
uptake of gases. Yet, research on the effect of water on secondary organic
aerosol (SOA) mass yields is not consistent. In this study, the SOA mass
yields of an α-pinene and m-xylene mixture, at a concentration of
60 µg m−3, were examined using an oxidation flow reactor
operated at a relative humidity (RH) of 60 % and a residence time of 160 s. Wet or dried
ammonium sulfate and ammonium nitrate seed particles were used. By varying
the amount of seed particle surface area, the underestimation of SOA
formation induced by the short residence time in flow reactors was confirmed.
Starting at a SOA mass concentration of ∼5 µg m−3, the
maximum yield increased by a factor of ∼2 with dry seed particles and on
average a factor of 3.2 with wet seed particles. Hence, wet particles increased
the SOA mass yield by ∼60 % compared to the dry experiment. Maximum
yield in the reactor was achieved using a surface area concentration of ∼1600 µm2 cm−3. This corresponded to a condensational
lifetime of 20 s for low-volatility organics. The O:C ratio of SOA on
wet ammonium sulfate was significantly higher than when using ammonium
nitrate or dry ammonium sulfate seed particles, probably due to differences
in heterogeneous chemistry.
Materialart:
Online-Ressource
ISSN:
1680-7324
DOI:
10.5194/acp-19-2701-2019
DOI:
10.5194/acp-19-2701-2019-supplement
Sprache:
Englisch
Verlag:
Copernicus GmbH
Publikationsdatum:
2019
ZDB Id:
2092549-9
ZDB Id:
2069847-1
