One-Year-Long Continuous and Synchronous Data Set of Fossil Carbon in Atmospheric PM2.5 and Carbon Dioxide in Debrecen, Hungary

Abstract

Radiocarbon investigation of atmospheric PM_2.5 aerosol synchronized with ¹⁴CO₂ observations began in Debrecen in the winter of 2010. The aim of the study was to determine the contemporary and fossil carbon fractions in the aerosol and to set them against the fossil CO₂ excess data referring to the same period. The mass of the collected PM_2.5 mode on prebaked quartz filters was determined gravimetrically, while its total carbon mass was calculated from the pressure of CO₂ gas produced after the combustion of the filters. As a result of the applied sampling and preparation method, the stable, nonvolatile carbon forms were principally studied. ¹⁴C measurements of the tiny aerosol bulk samples were performed using the EnvironMICADAS accelerator mass spectrometer at ATOMKI. The sample preparation method was tested using several blanks, standards, and real samples. Test results showed good reproducibility for the applied aerosol sample preparation and accelerator mass spectrometry (AMS) ¹⁴C analyses. Atmospheric fossil CO₂ excess data were calculated according Levin et al. (2003), using the ¹⁴C results of collected CO₂ samples measured by the gas proportional counting system at ATOMKI. Mass concentration of PM₁₀ involving the PM_2.5 mode in the city air exceeded the daily average of 50 µg/m³ (24-hr limit value in the EU) several times in 2011, mainly during the winter. The results showed that recently derived carbon most likely from domestic wood burning was causing the elevated carbon mass concentration of PM_2.5 in Debrecen at the time. In the course of the 1-yr-long continuous and systematic comparison of fossil carbon mass concentration of PM_2.5 mode and mole fraction of fossil excess of atmospheric CO₂, similar and synchronous trends were observed during the studied period in Debrecen.

DOI: 10.2458/azu_rc.57.18191