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| Titel |
Insights into the growth of newly formed particles in a subtropical urban environment |
| VerfasserIn |
F. Salimi, L. R. Crilley, S. Stevanovic, Z. Ristovski, M. Mazaheri, C. He, G. Johnson, G. Ayoko, L. Morawska |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-07), S.13475-13485 |
| Datensatznummer |
250120206
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| Publikation (Nr.) |
 copernicus.org/acp-15-13475-2015.pdf |
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| Zusammenfassung |
| The role of different chemical compounds, particularly organics, involved in
the new particle formation (NPF) and its consequent growth are not fully
understood. Therefore, this study was conducted to investigate the chemical
composition of aerosol particles during NPF events in an urban subtropical
environment. Aerosol chemical composition was measured along with particle
number size distribution (PNSD) and several other air quality parameters at
five sites across an urban subtropical environment. An Aerodyne compact
Time-of-Flight Aerosol Mass Spectrometer (c-ToF-AMS) and a TSI Scanning
Mobility Particle Sizer (SMPS) measured aerosol chemical composition
(particles above 50 nm in vacuum aerodynamic diameter) and PNSD (particles
within 9–414 nm in mobility diameter), respectively. Five NPF events, with
growth rates in the range 3.3–4.6 nm, were detected at two of the sites. The
NPF events happened on relatively warmer days with lower condensation sink
(CS). Temporal percent fractions of organics increased after the particles
grew enough to have a significant contribution to particle volume, while
the mass fraction of ammonium and sulfate decreased. This uncovered the
important role of organics in the growth of newly formed particles. Three
organic markers, factors f43, f44 and f57, were calculated and the
f44 vs. f43 trends were compared between nucleation and
non-nucleation days. K-means cluster analysis was performed on f44 vs. f43 data and it was found that they follow different patterns on
nucleation days compared to non-nucleation days, whereby f43 decreased
for vehicle-emission-generated particles, while both f44 and
f43 decreased for NPF-generated particles. It was found for the first
time that vehicle-generated and newly formed particles cluster in different
locations on f44 vs. f43 plot, and this finding can be potentially
used as a tool for source apportionment of measured particles. |
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