Size-segregated characterization of PM10 at the EMEP site Melpitz (Germany) using a five-stage impactor: a six year study

Abstract

Size-segregated particle samples were collected using a Berner 5-stage impactor (stages 1-5: 0.05-0.14-0.42-1.2-3.5-10 μm aerodynamic diameter). The means for all 169 days and for different categories of days were used for a characterization. The sorting criteria were (a) the distinction between winter (Wi, November to April) and summer (Su, May to October), (b) the distinction between air mass inflow from a sector West (W, 210°-320°) and from a sector East (E, 35°-140°). For the assignment of the air mass origin 96-h backward trajectories were used and four categories (WiW, WiE, SuW and SuE) with 48, 18, 42 and 29 days were established. The lowest mean particle mass concentrations were found for SuW and the highest for WiE with relative mass concentration distributions of 5.9, 28.2, 36.5, 18.0, and 11.4 % and 3.5, 22.7, 52.6, 16.7, and 4.5 % for stages 1-5, respectively. The mass closure for water soluble ions, water, organic material (OM) and elemental carbon (EC) accounts for 81-99 % of the gravimetric mass in Wi and for 60-81 % for Su, depending on the stage. The fractions of nitrate were relatively high for WiW while sulphate fractions are high for WiE. The estimated concentrations of secondary organic carbon (SOA) on stage 3 for WiW, WiE, SuW and SuE were 0.32, 1.25, 0.27 and 0.58 μgm − ³, respectively. The highest amount of SOA is found for WiE, representing 59 % of organic carbon (OC). The highest difference in the percentages of SOA in OC was found between winter (WiW 55 %, WiE 59 %) and summer (SuW and SuE 74 %) indicating photochemical processes during long-range transport. The mean Carbon Preference Indices (CPI) are highest for SuE (stage 4: 7.57 and stage 5: 9.82) resulting mainly from plant wax abrasion in the surrounding forests. For WiE the mean PAH concentration on stage 3 (9.7 ngm −3 ) is about five times higher than for WiW, indicating long range transport following domestic heating and other combustion processes.

The HD(CP)<sup>2</sup> Observational Prototype Experiment (HOPE) – an overview

“…is the TROPOS research station for the continuous physical and chemical in situ aerosol characterization of background aerosol characteristics in central Germany (Spindler et al, 2012). The site is located in a rural area, 40 km northeast of Leipzig (Fig.…”

“…COPS and the associated general observation period (GOP) that was prepared in the context of the Quantitative Precipitation Forecasting priority programme (SPP1167) of the German Science Foundation (DFG) (Crewell et al, 2008) aimed at the observation of orographically driven initiation of convection with supersites several tens of kilometres apart in strongly structured terrain. Complementary to COPS, HOPE covers a smaller domain with higher resolution and is accompanied by long-term supersite observations within the framework of the Terrestrial Environmental Observatories (TERENO) programme around the ground-based remote-sensing supersite Jülich Observatory for Cloud Evolution (JOYCE) , and the TROPOS long-term aerosol observatory in Melpitz (Spindler et al, 2012).…”

Hydroxymethanesulfonic acid in size-segregated aerosol particles at nine sites in Germany

“…Sampling was performed at nine sites in Germany (Fig. 2, (Spindler et al, 2010(Spindler et al, , 2012(Spindler et al, , 2013 Sampling was started whenever the weather forecast predicted favourable meteorological conditions (i.e. no precipitation and a constant air mass origin throughout the sampling day).…”

Continuous Measurement of Ambient Aerosol Liquid Water Content in Beijing

“…There are diverse methods to measure aerosol water content, e.g., gravimetric analysis to determine the amount of water associated with the mass of aerosol on a filter (McInnes et al, 1996;Lee and Hsu, 2000;Spindler et al, 2012), optical methods using Nephelometers or extinction cells (Carrico et al, 2000;Nessler et al, 2005;Kim et al, 2006), microscopy such as scanning electron microscope (SEM) and environmental transmission electron microscope (ETEM) (Ohta et al, 1998;Ebert et al, 2002;Wise et al, 2005), electrodynamic balance to study properties of single droplets of multicomponent systems (Tang and Munkelwitz, 1993;Tong et al, 2011;Davies et al, 2013;Zuend et al, 2013). Among all, the most frequently used is the hygroscopic tandem differential mobility analyzer (H-TDMA) (Liu et al, 1978;Rader and McMurry, 1986), which measures hygroscopic growth by size-selecting individual particles with a Differential Mobility Analyzer (DMA), exposing them to elevated or reduced RH and then measuring aerosol diameter change using a second DMA (Swietlicki et al, 2008;Kitamori et al, 2009;Ye et al, 2011;Wang et al, 2014).…”