Abstract
An hourly quantification of inorganic water-soluble PM10 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 data availability amounts to over 80% for the five-year measurement period from 2010 to 2014. 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 SO2 gas monitor, 0.84 (0.88), 0.79 (1.39), 0.85 (1.20) for the ACSM NO3−, SO42− and NH4+ 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−, NO3−, SO42− and NH4+, respectively. A HONO comparison with a batch denuder shows large scatter (R2 = 0.41). The MARGA HNO3 is underestimated compared to a batch and coated denuder with shorter inlets (slopes of 0.16 and 0.08, respectively). Less NH3 was observed in coated denuders for high ambient concentrations. Long-time measurements show clear daily and seasonal variabilities. Potential Source Contribution Function (PSCF) analysis indicates the emission area of particulate ions Cl−, NO3−, SO42−, NH4+, K+ and gaseous SO2 to lie in eastern European countries, predominantly in wintertime. Coarse mode sea salt particles are transported from the North Sea to Melpitz. The particles at Melpitz are nearly neutralised with a mean molar ratio of 0.90 for the five-year study. A slight increase of the neutralization ratio over the last three years indicates a stronger decrease of the anthropogenically emitted NO3− and SO42− compared to NH4+.
Highlights
Atmospheric 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)
In Central Europe, a significant amount of particulate matter consists of inorganic ions, including nitrate (NO3−), sulphate (SO42−), ammonium (NH4+), and chloride (Cl−) (e.g., Neusüß et al 2000; Spindler et al 2013; Rogula-Kozlowska 2015)
Ion detections of 80% were achieved for the gases (HONO, HNO3, SO2, and NH3) and the main ions (NO3−, SO42−, NH4+) for the entire measurement period in Melpitz from 2010 until 2014
Summary
Atmospheric 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). In Central Europe, a significant amount of particulate matter consists of inorganic ions, including nitrate (NO3−), sulphate (SO42−), ammonium (NH4+), and chloride (Cl−) (e.g., Neusüß et al 2000; Spindler et al 2013; Rogula-Kozlowska 2015) The quantification of these ions is predominantly performed by the standard method of filter sampling followed by offline analysis. Alternatives to particle measurements with a high time resolution are mass spectrometric systems, such as the Aerosol Mass Spectrometer (AMS) (e.g., Canagaratna et al 2007) and the Aerosol Chemical Speciation Monitor (ACSM) (e.g., Ng et al 2011) Both instruments offer the chemical analysis of major non-refractory ions within submicron particles. A large inter-comparison exercise was performed comparing the MARGA results with collocated and parallel measurements at the Melpitz site
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