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Climate change expected from increasing atmospheric CO₂ concentrations has been studied widely (IPCC, 1990). Further, it is recognized that cities are a major source of anthropogenic CO₂. However, few studies of CO₂ concentrations in, or near, cities have been conducted. A LI-COR infrared gas analyzer was operated at the Sunset Tower in a suburban region of Vancouver during different time periods in 1993 and 1994. Sampling revealed important information on seasonal and diurnal variations. The observed summertime concentrations show a clear diurnal signal around the expected upwind background concentration, and are described by a late afternoon minimum, and overnight maximum. The afternoon CO₂ minimum is attributed to the strength of biospheric photosynthesis and strong mixing of local anthropogenic sources within a large mixed layer. Poor nighttime mixing, lower mixed depths, and biospheric respiration account for the observed nighttime maximum, often more than 80 ppmv greater than the background concentration. A simple numerical multiple-box transport model was developed to simulate the observed diurnal pattern of CO₂ concentration at the suburban site. CO₂ emissions inventories for important mobile sources, stationary sources, and biospheric sources and sinks are calculated as input to the model for upwind fetch areas. Other CO₂ inputs include advection, entrainment from above the mixed layer and determination of the mixed layer depth. Results of both observations and modelling show large diurnal variation in CO₂ concentrations, and the importance of boundary layer structure (as defined by the mixed layer) on concentrations at a specific location. In terms of CO₂, the role of the city is placed in it global context.

Biogenic volatile organic compounds (VOCs) are a diverse class of hydrocarbon released during the normal physiological processes of some species of vegetation. These substances can participate in many chemical reactions and in some cases have potential to promote the formation of ground level ozone. The Fraser Valley located in southwestern British Columbia occasionally experiences these air pollution episodes during the summer. In order to effectively reduce the frequency and magnitude of these episodes, it is important that we understand the relative role of biogenic hydrocarbons from the abundant vegetated surfaces in the region. The thesis presents the results of measurements conducted on four common tree species in the lower Fraser Valley using a branch enclosure apparatus. Hydrocarbon emission rates from Cottonwoods trees were approximately one hundred times greater than those from coniferous trees and were dominated by the compound isoprene. Monoterpenoid emissions from four tree species were highly variable in magnitude and demonstrated no statistically significant relationship with temperature. Comparison of the observed results with a simple model from the literature shows relatively close agreement in the case of isoprene but poor agreement with monoterpene emissions. Results of these branch enclosure studies were extrapolated to larger scales to yield an areal emission rate assuming reasonable biomass densities. Isoprene measurements in this study reveal an areal emission rate approximately twenty times that of the assumed value in current emissions inventories. This discrepancy could be quite significant considering its magnitude and the possible sensitivity of the chemical reactions that produce ground level ozone to changes in isoprene concentration.

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Since 1992 the Department of Environmental Affairs and Tourism (DEAT), now the Department of Environmental Affairs (DEA), acknowledged that pollution and waste management governance was inadequate in dealing with South Africa’s changing social and industrial context. This triggered an extensive legislative revision, with the new National Environmental Management: Air Quality Act (No. 39 of 2004) (AQA) being partially implemented on 11 September 2005 and full implementation expected by 1 April 2010. The goal of this research was to develop a methodology for the delineation of the boundaries of air quality management areas in South Africa. The preliminary objective of the research was to identify the specific criteria that should be considered when developing the methodology. A review of the methodologies used internationally was undertaken, looking specifically at regions and countries with similar effects-based air quality legislation. The review concluded that the international practice regarding boundary determination was data intensive, relying heavily on the results of ambient air quality monitoring and the results of dispersion modelling based on comprehensive emissions inventories. Another commonality between the methodologies was the use of administrative boundaries as the borders of air quality management areas. South Africa has limited ambient air quality monitoring and there is no national emissions inventory for criteria pollutants. In the absence of this information an alternative approach was required. The next objective of the research was to identify or develop a proxy methodology for assessing the impact of each of these criteria to be used in the boundary determination. The criteria assessed as part of this research included, population density, emission criteria (industrial, mining and domestic), topography and administrative boundaries. A further objective of the research was to combine all the criteria to produce a single indicator or value as to the air pollution impact potential of the area under consideration. This methodology was then applied in the South African context. The final objective of the research was to assess the results of the application of the methodology on the regulatory framework proposed by the AQA, at the national, provincial and local government levels. The methodology has proved successful in the identification of areas with high air pollution impact potential in South Africa. This has allowed for a review of the boundaries proclaimed for the Vaal Triangle Airshed Priority Area and the Highveld Priority Area. In both cases significant revisions of the boundaries are recommended, however due to the controversial nature of these recommendations, it is proposed that these revisions are deferred until the five- yearly review phase of the priority area management plan. The results also recommended the proclamation of two additional national priority areas. The first was the proposed Magaliesberg Priority Area, which covers the north-western areas of Gauteng and the eastern areas of the North-West. This area combines the high density residential, commercial and industrial areas of Gauteng with the high density mining and industrial areas of the North-West. However, it is recommended that further ambient air quality monitoring and research is required prior to the proclamation of this national priority area. The second new national priority area proposed is the Waterberg Priority Area. This proclamation is a proactive declaration based on the proposed industrial developments earmarked for this area. Due to extensive coal reserves in the area, the development of additional coal-fired power generation, a coal to liquid facility and other coal beneficiation projects are currently under consideration. The research has identified five potential provincial priority areas. The provincial priority areas are associated with the major metropolitan centres in the country and their adjacent district municipalities. All of the proposed provincial priority areas, with the exception of the one proposed in Gauteng, require further ambient air quality monitoring and research prior to their proclamation. It is recommended that the City of Johannesburg / City of Tshwane provincial priority area be considered for immediate declaration. The review of the district and local municipalities identified in Table 24 of the National Framework highlighted the conservative nature of the initial assessment. The review amended the classification of 33 of the local municipalities, with 32 being reclassified downwards and only one being reclassified upwards. This also highlighted the subjective nature of the initial assessment. It is recommended that the local municipalities identified as having “Poor” or “Potentially Poor” air quality rating, be prioritised as potential sites in the national ambient air quality monitoring network and receive assistance in the development of their air quality management plans. This ensures that the limited financial and human resources assigned to air quality management in South Africa are deployed in those areas with the greatest need. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

In recent years there has been considerable advancement in our scientific understanding of the linkages and interactions between climate change and air quality. A warmer, evolving climate is likely to have severe consequences for air quality due to impacts on pollution sources and meteorology. The issues of poor air quality and anthropogenic induced climate change further share common sources of pollutants and thus options for control. The possibility to include these complex linkages to climate change in South Africa’s air quality policy, the National Environmental Management: Air Quality Act (Act No.39 of 2004) (the AQA), includes the use of local air quality management plans (AQMPs). The extent to which South African cities are currently incorporating climate change concerns into existing AQMPs and the opportunities for improved integration of these two issues was investigated using the eThekwini Municipality or the city of Durban as a case study. Climate change and air quality issues are currently dealt with separately in Durban, overlooking an opportunity to derive multiple benefits from integrative policies. This case study primarily focused on understanding the role that the AQMP could play in support of creating a low carbon resilient city through its influence on greenhouse gas (GHG) emissions. Emission inventories focusing on both air pollutants and GHG emissions were developed for two of the areas for intervention prioritised in Durban’s AQMP, namely the road transportation and industrial sectors. The emissions inventories were used as a basis to explore air pollution interventions that are likely to result in trade-offs or synergies (or co-benefits) for GHG mitigation. For the industrial sector it was found that the implementation of industrial energy efficiency and fuel switching measures would be favourable for co-benefits. In the case of road transport, reducing the vehicle kilometres travelled by privately owned motor vehicles and improving the efficiency of road freight transport offers the greatest potential for achieving co-benefits. The case study further illustrates that in the short-to medium-term air quality management (AQM) planning may help to promote climate change awareness and action toward climate change mitigation through improved co-ordination of industrial, energy and transport plans. The introduction of voluntary programmes, municipal by-laws and or regulatory guidance from the AQA, that support strategies with co-benefits is critical to ensure that local AQMPs can be used to promote reductions or avoidance of GHG emissions. In the long-term, climate change impacts on meteorological factors that influence air quality also need to be considered in AQMPs so that the most effective interventions can be selected to support the local government’s climate change adaptation goals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.

Interacting microbial associations capable of utilizing thiosulphate as an energy source were enriched/isolated from activated sludge, landfill site [mal covering soil and soil from an acid mine water drainage site. The isolates were designated Lf-I, Ws-2 and Am-3, respectively. Although hydrogen sulphide was the target molecule for gas biofiltration, thiosulphate, which is a key oxidized intermediate, was used in this study due to the difficulty of working with a toxic gas. Together with thiosulphate oxidation, the microbial associations were assessed for their abilities to oxidize dissolved sulphide to elemental sulphur. Physiological analyses (temperature, pH and substrate concentration optimization) were made with closed and open cultures while morphological characterization and species compositional changes were monitored by light and scanning electron microscopy (SEM). To investigate further functional and structural responses to physiological changes, denaturing-gradient gel electrophoresis (DGGE) separation of PCR-amplified 16S DNA gene fragments and Biolog GN microtitre plates were used. The associations were found to be active metabolically between 0 and 35°C, 15 and 50°C, and 15 and 45°C, with optimum temperatures of 25, 40 and 35°C for Lf-l, Ws-2 and Am-3, respectively. The optimum pH range for microbial association Lf-l was between 3 and 4. The maximum specific growth rates of associations Lf-l , Ws-2 and Am-3 were 0.08, 0.06 and 0.03 h~l , respectively. Components of all three Gram negative rod-dominated associations were motile and displayed anaerobiosis. During open culture cultivation the species complement of Lf-l , as determined by morphological analysis, changed. The same association oxidized sulphide (40 ppm) to sulphur although Ws-2 and Am-3 did not have this capacity. Biolog GN plates detected pH-effected species compositional changes in Lf-l and these were confirmed by DGGE. The same technique showed that enrichment had occurred in the Biolog GN wells. Species composition changes also resulted in response to different pH values (2 to 9), temperatures (5 to 40°C) and dilution rates (0.003 to 0.09 h-1 ), but activity changes were not always accompanied by population profile changes. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2000.

The industrial basin in the south of Durban is an area of ongoing contention between the residents and major industries, regarding environment health issues especially poor air quality resulting from industrial air pollution. This region is a result of poor urban planning that began in the early 1960's which saw rapid industrialisation alongside expanding communities, which has now resulted in a major environmental dilemma for the city of Durban, eThekwini Municipality. Durban is seen as a key area of growth in South Africa: it has the busiest harbour on the continent; it is a regional hub of the chemical industry and a major motor and metal manufacturer centre; and Durban's population continues to grow at ~4% per annum, all of which are destined to have significant environmental impacts. As part of a large epidemiological study and health risk assessment in this industrial basin, particulate matter smaller than 10 microns (PM10) and sulphur dioxide (S02) were measured in seven community sites across Durban: four in the South, (Wentworth, Bluff, Merebank and Lamontville) and three in the north (Kwamashu, Newlands East and Newlands West). The south sites are located in an industrial basin near two petroleum refineries and a paper mill, while the north comparison sites are ~25 km North West from major industries in the Basin. 24 hour PMIO samples were collected gravimetrically every day during four, three-week intensive phases and thereafter every 6th day using high, medium and low volume samplers. S02 was monitored every 10 minutes with active continuous analysers (European monitor labs and API) according to internationally accepted methods. Rigorous quality assurance methods were followed for both pollutants. S02 followed a distinct spatial distribution where the mean difference in S02 concentrations between the southern and the northern region was 6.7 ppb, while for PMIO similar concentrations were found across all sites with the highest mean concentration at Ngazana in the north (59 Ilg/m3) > Assegai in the south (~58 Ilg/m3) with all other sites ~ I to 10 Ilg/m3 less in mean concentration. S02 diurnal variations display two maxima from 5:00AM to 10:00AM being repeated in the latter part of the day from 20:00PM to 24:00PM. Seasonal pattern of PMIO and SOz to a lesser extent, display very similar mean variations for all sites - the highest levels seen in the colder months of May; June, July of 2004 and 2005. Weak to strong intersite correlations were found for SOz ranging from 0.16 to 0.22 among the south sites; 0.06 to 0.64 among the north sites, while PM10 ranged from 0.73 to 0.88 among the south sites and 0.86 to 0.91 among the north sites. A cross regional correlation of PMIO by sites displayed a moderate to strong correlation ranging from 0.73 to 0.88, while intrasite SOz with PMIO correlations displayed weak to moderate correlations from 0.35 to 0.53. Meteorological conditions wind speed, temperature, pressure and humidity differed across Durban. The difference in temperature and humidity between "summer" and "winter" was on average, approximately 7 °c and 10-15% respectively. These temperature and humidity patterns closely track the increase in SOz and PM10 during "winter" explaining the effects of winter inversions on pollutant levels. Also of interest is the variability of meteorological parameters between south and north Durban with the two regions being 35 km apart. Meteorological conditions impact differently on each pollutant e.g. rain is more likely to decrease PMIO concentrations than it would SOz In general relationships between pollutants and meteorological parameters differ on a site-bysite basis. For instance, wind direction at Assegai increases SOz levels whereas wind direction at Ngazana decreases SOz levels. Another independent variable that proved to be a consistent and important predictor for SOz and PM10 across most sites was the previous day's pollution events; this was a much stronger predictor for PM10 rather than SOz. These findings suggest that pollutants are not fully removed from the atmosphere during a 24 hour period and that the previous day's pollution levels will contribute to current levels, a finding that has important implication when implementing early warning pollution systems as envisaged for the Durban South Basin. / Thesis (MMed)-University of KwaZulu-Natal, 2006.

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