![]() Varying meteorological conditions influence these physical and chemical properties in a very complex manner (Vecchi et al. A slight increase of the neutralization ratio over the last three years indicates a stronger decrease of the anthropogenically emitted NO 3 − and SO 4 2− compared to NH 4 +.Ītmospheric processing of particles and their precursor gases from terrestrial, marine, and various anthropogenic primary and secondary sources determines the chemical composition and physical properties of particulate matter (PM). The particles at Melpitz are nearly neutralised with a mean molar ratio of 0.90 for the five-year study. Coarse mode sea salt particles are transported from the North Sea to Melpitz. Potential Source Contribution Function (PSCF) analysis indicates the emission area of particulate ions Cl −, NO 3 −, SO 4 2−, NH 4 +, K + and gaseous SO 2 to lie in eastern European countries, predominantly in wintertime. Long-time measurements show clear daily and seasonal variabilities. Less NH 3 was observed in coated denuders for high ambient concentrations. The MARGA HNO 3 is underestimated compared to a batch and coated denuder with shorter inlets (slopes of 0.16 and 0.08, respectively). A HONO comparison with a batch denuder shows large scatter (R 2 = 0.41). Comparisons were performed for the evaluation of the MARGA, resulting in coefficients of determinations (slopes) of 0.91 (0.90) for the measurements against the SO 2 gas monitor, 0.84 (0.88), 0.79 (1.39), 0.85 (1.20) for the ACSM NO 3 −, SO 4 2− and NH 4 + measurements, respectively, and 0.85 (0.65), 0.88 (0.68), 0.91 (0.83), 0.86 (0.82) for the filter measurements of Cl −, NO 3 −, SO 4 2− and NH 4 +, respectively. The data availability amounts to over 80% for the five-year measurement period from 2010 to 2014. As shown by examples from field experiments, the instrument provides sufficient precision (3-9%), even at low ambient concentrations, to resolve vertical gradients and calculate surface-atmosphere exchange fluxes undertypical meteorological conditions of the atmospheric surface layer using the aerodynamic gradient technique.An hourly quantification of inorganic water-soluble PM 10 ions and corresponding trace gases was performed using the Monitor for AeRosols and Gases in ambient Air (MARGA) at the TROPOS research site in Melpitz, Germany. The instrument demonstrates very good linearity and accuracy for liquid and selected gas phase calibrations over typical ambient concentration ranges. Through the use of syringe pumps, IC preconcentration columns, and high-quality purified water, the system achieves detection limits (3sigma-definition) under field conditions of typically: 136/207,135/114, 29/ 22,119/92, and 189/159 ng m(-3) for NH3/NH4+, HNO3/NO3-, HONO/ NO2-, HCl/Cl- and SO2/SO4(2-), respectively. Online (real-time) analysis using ion chromatography (IC) for anions and flow injection analysis (FIA) for NH4+ and NH3 provide a half-hourly averaged gas and aerosol gradients within each hour. Gas and aerosol samples are collected simultaneously at two heights using rotating wet-annular denuders and steam-jet aerosol collectors, respectively. Here, we present a new automated instrument for semicontinuous gradient measurements of water-soluble reactive trace gas species (NH3, HNO3, HONO, HCl, and SO2) and their related aerosol compounds (NH4+, NO3-, Cl-, SO4(2-)). ![]()
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