A new analytical method has been developed for the determination of inorganic species or arsenic (arsenite and arsenate); in addition, a new sample preparation method for the determination of these species in atmospheric particulate matter has also been developed. In this procedure, As(III) and As(V) are efficiently separated in a two-step reduction procedure from a solution of HCl. In the first step, a slurry of Zn metal powder is used to reduce As(III) to arsine (AsH₃). Immediately following, NaBH₄ is used to reduce As(V) to AsH₃. The arsine produced during each reduction is detected in an N₂-H₂ air-entrained flame by atomic absorption spectroscopy. In the sample preparation method, sections of quartz or PTFE filters containing atmospheric particulate matter are leached in 10⁻⁴ N HCl for up to 1 hour at 90°C. This procedure quantitatively removes As(III) and As(V) from either filter type. However, small changes in the As(III)/As(V) ratio i.e., oxidation of As(III) were observed when the arsenic species were leached from quartz filters. Therefore, it appears that PTFE would be the preferred filter medium if arsenic speciation is to be performed. When atmospheric particles are present on either filter type, the technique of standard addition is necessary in order to obtain the most accurate results. The combined sample preparation and analysis procedure has a precision of about 10%, 8% and 13% for As(III), As(V) and the As(III)/As(V) ratio, respectively. Atmospheric particulate matter samples collected in Tucson, Arizona, were analyzed for As(III) and As(V) concentrations using the newly developed method. The results of this study indicate that both As(III) and As(V) are present in collected samples of atmospheric particulate matter. Arsenic (V) was observed in all 14 of the samples, while As(III) was measurable in half of the samples. The As(III)/As(V) ratio was determined to be in the range from less than 0.05 to 1. An atmospheric detection limit for either species of 0.09 ng m⁻³ was obtained.

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Airborne particulate matter (PM) has important harmful effects on human health, as well as a number of other important atmospheric effects. Although progress has been made in understanding the sources and effects of PM, there remains considerable uncertainty on a number of issues, including the nature of a lot of the carbonaceous material, which comprises 30{50% on average of PM mass. This project aims to compare different methods of PM measurement, and contribute understanding to the nature and origin of the carbonaceous fraction of PM. Daily samples of PM10 were collected from three sites in the Edinburgh area using Partisol-Plus 2025 Sequential Air Samplers: 1) Urban Background (20 August 2008 until 21 April 2010); 2) Rural (25 February 2009 until 21 April 2009); and 3) Roadside (10 September 2009 until 21 April 2010). These localities provided PM that was, respectively, representative of: 1) city-wide background air; 2) air at a location distanced from population centres, roads and industrial areas; and 3) air influenced by the emissions associated with traffic. Gravimetric PM10 concentration (µgm-3) was determined for each daily filter sample, after a blank correction to compensate for the relative humidity (RH)-influenced change in filter mass over time. The correction was successful, with good agreement attained between the Partisol and a PM10 Tapered Element Oscillating Microbalance Filter Dynamics Measurement System (TEOM-FDMS) co-located at the Urban Background site. The general levels of PM10 measured in this monitoring campaign indicate that the air in Edinburgh was relatively clean. The main factor causing exceedance of the daily European Union (EU) limit value was shown to be transport of PM10 from areas of mainland Europe. High PM10 concentrations were also strongly associated with calm weather conditions in Edinburgh, which allowed the build-up of particulate pollution over time. Aethalometer-equivalent daily concentrations of black carbon (BC) were determined by measuring the optical reflectance of the PM10 filters from the Partisol samplers. The conversion of reflectance values to BC concentrations relied on a number of correction factors, which may have impacted on the accuracy of the results with time and location. The concentration of BC in Edinburgh was shown to be relatively low, with the daily variation being controlled by local emissions and meteorology. BC as a proportion of PM10 increased with sampling location in the order: Rural < Urban Background < Roadside. Predominantly traffic-related BC concentrations increased during periods of low wind speed and were not greatly influenced by long-range transport of aerosol. Daily water-soluble organic matter (WSOM) concentrations were obtained by aqueous extraction of the filter samples and measurement of the dissolved organic carbon (DOC). About 11% on average of the Edinburgh PM10 was WSOM. The majority of this WSOM seemed to have originated from air masses outside of the city, although there was a minor contribution from urban traffic sources. A solid phase extraction (SPE) procedure was used to isolate about one-third of the WSOM as hydrophobic compounds and this revealed a relative increase in the amount of less oxygenated material from traffic sources. Higher than average WSOM concentrations were strongly associated with calm weather conditions that allowed the transient build-up of particle concentrations. Some of the peaks in WSOM concentration were related to the transport of air masses from areas of mainland Europe where biogenic secondary organic aerosol (SOA) and biomass burning were likely sources. Analysis of the WSOM samples by UV-Vis absorption spectroscopy showed clear seasonal trends in the composition of hydrophobic watersoluble organic matter (HWSOM), interpreted as predominance of lower molecular weight aliphatic compounds in summer but predominance of larger aromatic and polyconjugated compounds in winter. Raman spectra were obtained for different carbonaceous reference materials. The results of curve fitting for these spectra gave D1 band full width at half maximum (FWHM) values that distinguished between diesel exhaust particles from a local bus and a humic acid sample. Analysis of Edinburgh PM10 samples using Raman microspectroscopy (RM) showed a variation in the structural order of the carbon compounds present between that of soot and HUmic-LIke Substances (HULIS), with a tendency towards more soot-like material being present. There was no strong relationship between carbonaceous order and BC concentration, showing that coloured organic compounds have the potential to influence reflectance measurements. The combination of these measurement approaches has yielded insights into the nature and variation in carbonaceous PM material with time and sampling location.

Air pollution is one of the major environmental issues. It can cause adverse health effects such as cancer, cardiovascular diseases and high mortality rates. High population density is a huge contributory factor of air pollution in cities and urbanized areas. The third biggest city of the Czech Republic, Ostrava the subject of this thesis, is one of the most densely polluted areas of the country. The main air pollutants of concern are suspended particles and poly aromatic hydrocarbons. Ostrava's high proportion of heavy industry is a major source of air pollution compared to the rest of the Czech Republic. Other sources of air pollution are transport, local heating and possibly a pollution transfer from a neighboring industrial region in Poland. This thesis deals mainly with long term time series, including air pollutants (PM10, SO2, NOx), and meteorological variables. Information about the opening and closing of industrial plants can be considered as an added value to this work. The purpose of this data thesis is to compare the concentration levels before and after the closing or opening of particular industrial plants in the city of Ostrava during the last 35 years. So far no one has utilized these data sets for comprehensive analyses. Key words: Urban area, Emission, PM10, SO2, Industry

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2015.

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

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published_or_final_version / Journalism and Media Studies Centre / Master / Master of Journalism

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