10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Comparison of the Particle Growth Rates at Three Background Stations in the Czech Republic
Adéla Holubová Šmejkalová, HELENA PLACHÁ, Bitter Miroslav, Nadežda Zíková, Vladimír Ždímal, Charles University
Abstract Number: 697 Working Group: Aerosol Physics
Abstract Atmospheric aerosols as ubiquitous particles affect besides human health also climate. One of the key phenomena strongly affecting climate is new particle formation (NPF) and their consequent growth. NPF has been observed in many types of environments and geographical locations (Dall’Osto et al., 2018, Kulmala et al. 2004, Pushpawela et al. 2018, Sitho et al. 2006).
NPF and growth rates are controlled by several factors (concentration of pre-existing aerosols, precursor gases, air masses origin, meteorological conditions, and solar radiation) that are closely related to a sampling site (Jeong et al. 2010 , Nieminen et al. 2012). To explore possible differences in particle growth rates at various locations, measurements of number size distributions of atmospheric aerosol at three background stations in the Czech Republic were carried.
Two stations - Ústí nad Labem (50°39´39"N, 14°2´35"E, 147 m a.s l.) and Lom (50°35´8"N, 13°40´ 24"E, 265 m a.s.l.) are situated in northern, industrial part of the Czech Republic. Ústí nad Labem is urban background station in residential and commercial zone. Lom is rural background station in industrial and natural zone. National atmospheric observatory Košetice (NAOK – 49°34´24"N, 15°4´49"E, 534 m a.s.l.) is located in Czech-Moravian Highland. NAOK is rural background station in agricultural and natural zone.
The number size distributions were measured by aerosol spectrometers SMPS (IfT Tropos) in size range 10 to 800 nm. SMPS data were evaluated from March 1 to August 31, 2017. The growth rate (GR) of the particles freshly formed during the NPF event days was estimated by time evolution of the geometric mean diameter (GMD) of particles smaller than 100 nm. NPF event days were determined by Dal Maso et al. (2005) classification. Condensation sink (CS) was calculated by integration over the aerosol particle size distribution according to Kulmala et al. (2005).
Based on the calculated GR10, CS values and NPF frequencies, the three locations were compared. Results from 24/7 air quality monitoring gives evidence that Ústí nad Labem and Lom are more polluted locations than NAOK. Average PM10 concentrations at Ústí nad Labem and Lom fluctuated around 20 µg•m-3, SO2 ranged from 4 to7 µg•m-3 and NO2 varied between 8 and 19 µg•m-3. Average concentrations at NAOK were 15 µg•m-3, 2 µg•m-3 and 6 µg•m-3, for PM10, SO2 and NO2, respectively.
We observed 52 NPF event days at Lom, 47 NPF event days at NAOK and 43 NPF event days at Ústí nad Labem. GR10 was similar at Ústí nad Labem and Lom stations (median slightly over 3 nm•h-1). At NAOK, median of GR10 was 2.6 nm•h1. On average, CS was higher by a factor of 1.3 at Ústí nad Labem and Lom stations compared to NAOK (median 0.007s-1). Similarities of GR10 and CS between Ústí nad Labem and Lom stations can be caused by a common source, chemical industry, besides other things. In cases when GR was higher than median, pollutant concentrations were slightly higher, especially SO2 concentrations at Lom station.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654109 and is supported by Ministry of Education, Youth and Sports of the Czech Republic within project ACTRIS-CZ - LM2015037.