Determination of PM1 Sources at a Prague Background Site during the 2012–2013 Period Using PMF Analysis of Combined Aerosol Mass Spectra

Otakar Makeš,Vladimír Ždímal,Jaroslav Schwarz,Petr Vodička,Guenter Engling

doi:10.3390/atmos13010020

Abstract

Two intensive measurement campaigns using a compact time-of-flight aerosol mass spectrometer were carried out at the suburban site in Prague (Czech Republic) in summer (2012) and winter (2013). The aim was to determine the aerosol sources of the NR-PM1 fraction by PMF analysis of organic (OA) and inorganic aerosol mass spectra. Firstly, an analysis of the OA mass spectra was performed. Hydrocarbon-like OA (HOA), biomass burning OA (BBOA), and two types of oxygenated OA (OOA1) and (OOA2) were identified in summer. In winter, HOA, BBOA, long-range oxygenated OA (LROOA), and local oxygenated OA (LOOA) were determined. The identified HOA and BBOA factors were then used as additional input for the subsequent ME-2 analysis of the combined organic and inorganic spectra. This analysis resulted in six factors in both seasons. All of the previously reported organic factors were reidentified and expanded with the inorganic part of the spectra in both seasons. Two predominantly inorganic factors ammonium sulphate (AMOS) and ammonium nitrate (AMON) were newly identified in both seasons. Despite very similar organic parts of the mass profiles, the daily cycles of HOA and LOOA differed significantly in winter. It appears that the addition of the inorganic part of the mass profile, in some cases, reduces the ability of the model to identify physically meaningful factors.

Highlights

Atmospheric aerosol (AA), the suspension of fine solid or liquid particles in the air, is an important area of research due to its effect on climate [1,2], visibility [3], hydrological cycle [4,5], and for its harmful effect on human health [6,7]
This paper presents the results of the assessment of atmospheric aerosol sources determined on the principle of receptor modelling, using factor analysis
This may be explained by the existence of a residential area adjacent to the measuring stations, where some of the houses are heated with coal or wood boilers [52]

Summary

Introduction

Atmospheric aerosol (AA), the suspension of fine solid or liquid particles in the air, is an important area of research due to its effect on climate [1,2], visibility [3], hydrological cycle [4,5], and for its harmful effect on human health [6,7]. Organic aerosols (OAs) are still poorly described for thousands of compounds originating from various anthropogenic and natural sources. Primary organic aerosols (POAs), originating mostly from combustion, are aging in the atmosphere, forming part of the secondary OA (SOA) through physical and chemical processes such as oxidation, nucleation, and condensation [8]. An additional part of SOA is formed by a chemical reaction from various organic gaseous precursors both of natural and anthropogenic origin. The inorganic part of the aerosol matter is better explored due to a smaller number of chemical species and less complex chemistry, it is important to include inorganic aerosol (IA) if we want to perform a comprehensive analysis of aerosol sources influencing the measurement site because IA represents from 10 to 80% of total submicron aerosol mass [9]. Understanding how aerosol is produced and evolved in the atmosphere is an essential step in defining strategies to reduce aerosol concentrations in the atmosphere

Objectives

Methods

Results

Conclusion