Magdalena Kistler

Oxidative potential of PM10 and PM2.5 collected at high air pollution site related to chemical composition: Krakow case study

Measurements of the oxidative potential (OP) of airborne particulate matter may be applied for the assessment of the health-based exposure by integrating various biologically relevant properties of particles. This study aimed at the determination of oxidative activity of two size fractions of particulate using the ascorbic acid (AA) and reduced glutathione (GSH) assay. Samples of PM were collected in Krakow, one of the most polluted cities in Poland, in the city centre. Samples were collected during wintertime, when heating sources used in residential areas have significant influence on the concentrations of particulate matter in the air. PM10 and PM2.5 concentrations varied from 8.9 to 92.5xa0μgxa0m−3. Samples were chemically analysed for elemental carbon, organic carbon, ions and metals. PM2.5 was found as a more oxidative active fraction, where OPAA and OPGSH depletions were up to 81.7 and 132.0xa0μgxa0m−3, respectively. The average values of OPAA of PM10 and PM2.5 were similar and equalled 40.8 and 37.2xa0μgxa0m−3, respectively. The average value of OPGSH of PM2.5 equalled 56.7xa0μgxa0m−3 and was 3.5 times higher than OPGSH of PM10. The loss of AA amount in PM10 and PM2.5 and the depletion of GSH in PM2.5 were best described by the pseudo second-order kinetics model. The kinetics of the GSH depletion reaction in PM10 was best described by the pseudo first-order kinetics model. The strong correlations between carbonaceous and metallic constituents of PM and oxidative potential suggest their relevance in participation in oxidative activity of particulate matter.

Chemical characterization of PM 2.5 collected from a rural coastal island of the Bay of Bengal (Bhola, Bangladesh)

This work focuses on the chemical characterization of fine aerosol particles (PM2.5) collected from a rural remote island of the Bay of Bengal (Bhola, Bangladesh) from April to August, 2013. PM2.5 particle-loaded filters were analyzed for organic carbon (OC), elemental carbon (EC), water-soluble ions, and selected saccharides (levoglucosan, mannosan, galactosan, arabitol, and mannitol). The average PM2.5 mass was 15.0u2009±u20096.9xa0μgxa0m−3. Organic carbon and elemental carbon comprised roughly half of the analyzed components. Organic carbon was the predominant contributor to total carbon (TC) and accounting for about 28% of PM2.5 mass. Secondary organic carbon (SOC) was inferred to be ~u200926% of OC. The sum of ions comprised ~u200927% of PM2.5 mass. The contribution of sea salt aerosol was smaller than expected for a sea-near site (17%), and very high chloride depletion was observed (78%). NssSO42− was a dominant ionic component with an average concentration of 2.0xa0μgxa0m−3 followed by Na+, NH4+, and nssCa2+. The average concentration of arabitol and mannitol was 0.11 and 0.14xa0μgxa0m−3, respectively, while levoglucosan and its stereoisomers (mannosan and galactosan) were bellow detection limit. NH4+/SO42− equivalent ratio was 0.30u2009±u20090.13 indicating that secondary inorganic aerosol is not the main source of SO42−. Enrichment factor (EF) analysis showed that SO42− and NO3− were enriched in atmospheric particles compared to sea aerosol and soil indicating their anthropogenic origin. Higher OC/EC ratio (3.70u2009±u20090.88) was a good indicator of the secondary organic compounds formation. Other ratios (OC/EC, K+/EC, nssSO42−/EC) and correlation analysis suggested mixed sources for carbonaceous components. Arabitol and mannitol both showed strong correlation with EC having R2 value 0.89 and 0.95, respectively. Air mass trajectories analysis showed that concentrations of soil and anthropogenic species were lower for air masses originating from the sea (May–August) and were higher when air came from land (April).

Aerosol composition and microstructure in the smoky atmosphere of Moscow during the August 2010 extreme wildfires

This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal–optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.