Articles | Volume 16, issue 14
https://doi.org/10.5194/acp-16-8715-2016
https://doi.org/10.5194/acp-16-8715-2016
Research article
 | 
18 Jul 2016
Research article |  | 18 Jul 2016

Regional effect on urban atmospheric nucleation

Imre Salma, Zoltán Németh, Veli-Matti Kerminen, Pasi Aalto, Tuomo Nieminen, Tamás Weidinger, Ágnes Molnár, Kornélia Imre, and Markku Kulmala

Abstract. Secondary aerosol particle production via new particle formation (NPF) has been shown to be a major contributor to the global aerosol load. NPF has also been observed frequently in urban environments. Here, we investigate the effect of regional NPF on urban aerosol load under well-defined atmospheric conditions. The Carpathian Basin, the largest orogenic basin in Europe, represents an excellent opportunity for exploring these interactions. Based on long-term observations, we revealed that NPF seen in a central large city of the basin (Budapest) and its regional background occur in a consistent and spatially coherent way as a result of a joint atmospheric phenomenon taking place on large horizontal scales. We found that NPF events at the urban site are usually delayed by > 1 h relative to the rural site or even inhibited above a critical condensational sink level. The urban processes require higher formation rates and growth rates to be realized, by mean factors of 2 and 1.6, respectively, than the regional events. Regional- and urban-type NPF events sometimes occur jointly with multiple onsets, while they often exhibit dynamic and timing properties which are different for these two event types.

Download
Short summary
We revealed that NPF seen in a central large city of the Carpathian Basin, Budapest, and its regional background occur in a consistent and spatially coherent way as a result of a joint atmospheric phenomenon taking place on large horizontal scales.
Altmetrics
Final-revised paper
Preprint