Relationship between the Optical Properties and Chemical Composition of Urban Aerosol Particles in Lithuania

• Published in: Advances in meteorology Vol. 2018; no. 2018; pp. 1 - 10
• Main Authors: Ulevicius, Vidmantas, Dudoitis, Vadimas, Plauškaitė, Kristina, Pauraite, Julija
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2018; Hindawi; John Wiley & Sons, Inc; Hindawi Limited
• Subjects: Absorption; Aerosol optical properties; Aerosol particles; Aerosols; Albedo; Albedo (solar); Atmosphere; Atmospheric aerosols; Atmospheric chemistry; Biomass burning; Black carbon; Calibration; Carbon; Chemical composition; Chemical speciation; Coefficients; Emissions; Hydrocarbons; Light; Mass spectra; Mathematical analysis; Measurement techniques; Nephelometers; Optical properties; Organic chemistry; Outdoor air quality; Physics; Scattering; Segregation; Speciation; Urban areas; Wavelength; Lithuania; China
• ISSN: 1687-9309; 1687-9317
• DOI: 10.1155/2018/8674173

In situ investigation results of aerosol optical properties (absorption and scattering) and chemical composition at an urban background site in Lithuania (Vilnius) are presented. Investigation was performed in May-June 2017 using an aerosol chemical speciation monitor (ACSM), a 7-wavelength Aethalometer and a 3-wavelength integrating Nephelometer. A positive matrix factorisation (PMF) was used for the organic aerosol mass spectra analysis to characterise the sources of ambient organic aerosol (OA). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass-burning OA (BBOA), more and less oxygenated OA (LVOOA and SVOOA, respectively), and local hydrocarbon-like OA (LOA). The average absorption (at 470 nm) and scattering (at 450 nm) coefficients during the entire measurement campaign were 16.59 Mm−1 (standard deviation (SD) = 17.23 Mm−1) and 29.83 Mm−1 (SD = 20.45 Mm−1), respectively. Furthermore, the absorption and scattering Angström exponents (AAE and SAE, respectively) and single-scattering albedo (SSA) were calculated. The average AAE value at 470/660 nm was 0.97 (SD = 0.16) indicating traffic-related black carbon (BCtr) dominance. The average value of SAE (at 450/700 nm) was 1.93 (SD = 0.32) and could be determined by the submicron particle (PM1) dominance versus the supermicron ones (PM > 1 µm). The average value of SSA was 0.62 (SD = 0.13). Several aerosol types showed specific segregation in the SAE versus SSA plot, which underlines different optical properties due to various chemical compositions.