 |
| Titel |
Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation |
| VerfasserIn |
Y. Zheng, N. Unger, A. Hodzic, L. Emmons, C. Knote, S. Tilmes, J.-F. Lamarque, P. Yu |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-08), S.13487-13506 |
| Datensatznummer |
250120207
|
| Publikation (Nr.) |
 copernicus.org/acp-15-13487-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Globally, secondary organic aerosol (SOA) is mostly formed from emissions of
biogenic volatile organic compounds (VOCs) by vegetation, but it can be
modified by human activities as demonstrated in recent research.
Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to
play a critical role in the chemical formation of low volatility compounds.
We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric
Model version 4 with chemistry (CAM4-chem) by implementing a 4-product
volatility basis set (VBS) scheme, including NOx-dependent SOA yields
and aging parameterizations. Small differences are found for the no-aging
VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA
ratio are found for the aging scheme. The predicted organic aerosol amounts
capture both the magnitude and distribution of US surface annual mean
measurements from the Interagency Monitoring of Protected Visual
Environments (IMPROVE) network by 50 %, and the simulated vertical
profiles are within a factor of 2 compared to aerosol mass spectrometer
(AMS) measurements from 13 aircraft-based field campaigns across different
regions and seasons. We then perform sensitivity experiments to examine how
the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide
(NO) emissions in different regions. We find limited SOA reductions of 0.9–5.6, 6.4–12.0 and 0.9–2.8 % for global, southeast US
and Amazon NOx perturbations, respectively. The fact that SOA
formation is almost unaffected by changes in NOx can be largely
attributed to a limited shift in chemical regime, to buffering in chemical
pathways (low- and high-NOx pathways, O3 versus NO3-initiated
oxidation) and to offsetting tendencies in the biogenic versus anthropogenic
SOA responses. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|