Vaal Triangle Research Articles

A Step towards CO2 Sequestration through Mineral Carbonation: Using Ammonium-Based Lixiviants for the Dissolution of Calcium from Iron-Making Blast Furnace Slag

In recent years, technical processes for the sequestration of CO2 through industrial waste mineral carbonation have been explored and developed. There is a large portfolio of carbon capture, utilisation, and storage (CCUS) techniques that have been employed in laboratories and at pilot scale. These include geological storage, ocean storage, and mineralisation by carbonate ores. In view of this, the main purpose of this research was to investigate and explore chemical variables, particularly ammonium salts as lixiviants for calcium mineral extraction from iron-making slag. The slag in use was acquired from a steel mill in the Vaal Triangle Region in Gauteng, South Africa. The experimental test work was conducted using different ammonium lixiviants, namely, NH4NO3, NH4Cl, and CH3COONH4, to understand the influence of anion type as well as possible differences in mechanisms of interactions. Lixiviant concentration as well as reaction time were varied in this research study. The three selected ammonium-based lixiviants showed different extents of calcium extraction owing to differences in the anion groups. NH4NO3, NH4Cl, and CH3COONH4 were found to be capable of dissolving 50% to 80% of the calcium from the selected slag for different molar concentrations. Anion type and leaching time also had significant influences on the leaching of calcium from the slag. Rapid pH degradation resulted in better calcium extraction capabilities. This work has shown that the selected ammonium salts have the potential to be lixiviants for calcium dissolution from iron-making blast furnace slags. These lixiviants would, therefore, be important to consider during calcium mineral carbonation for CO2 sequestration.

Inclusion of learners with learning disabilities in the Vaal Triangle mainstream classrooms.

South Africa adopted a policy on inclusive education in 2001 to ensure that all learners are accommodated and accepted in the classrooms despite their differences. This study was aimed at exploring the inclusion of learners with learning disabilities in mainstream primary schools for teaching and learning. This study followed a qualitative approach embedded in a descriptive phenomenological design. Data were generated through in-depth interviews with individual participants and were analysed thematically for content. Six teachers from six different mainstream primary school classrooms were purposefully selected for the study. Findings revealed that overcrowding, time constraints and lack of parental involvement impede the inclusion of learners with learning disabilities in mainstream classrooms. However, teachers use: (1) multi-level teaching, (2) concrete teaching and/or learning aids, (3) differentiated instruction and (4) code-switching in accommodating learners with learning disabilities. This study argues that for learners with learning disabilities to be more included in mainstream classrooms, the learner population should be reduced to a maximum of 30 learners per class, and collaboration with parents should be enhanced. Also, the arrangement of learners for teaching and learning could be limited to small groups consisting of four to five learners. Multi-level teaching and differentiated instruction should be applied in settings that do not require learners to be separated from their peers without learning disabilities. This study will help improve teachers' inclusive classroom pedagogical practices for all learners including those with learning disabilities.

Dimensional Analysis of Service Fairness on Service Quality and Customer Satisfaction: A Local Municipality study

The recent series of service delivery protests directed at various local municipalities across South Africa, as frequently reported in the media, render it indispensable to examine the underlying association between service fairness, service quality and customer satisfaction within local municipalities in the country. The objective of the study is to investigate the impact of service fairness on service quality and customer satisfaction from the South African local municipal service context. A structured questionnaire elicited data through a convenient sample of 400 rates and taxes payers within three municipal districts in the Vaal Triangle. Descriptive statistics, correlations and regression analysis were used to evaluate relationships between the study constructs. Two of the four predictor variables, namely interactive and informational fairness showed significant predictive relationships towards service quality in municipality services provision among rates and taxes payers. Service quality towards customer satisfaction also emerged as a significant predictor. Municipality managers should embrace customer interaction and participation because customers evaluate the degree of service fairness displayed by the municipal employees and its effects of the service they deliver.

Temperature modifies the association between air pollution and respiratory disease hospital admissions in an industrial area of South Africa: The Vaal Triangle Air Pollution Priority Area

Background: Epidemiological studies reported independent effects of air pollution and temperature on health, yet these twoexposures are often treated as separate risk factors. Few studies investigated temperature effect modification on the health effects ofair pollution in Africa and none examined the effects of black carbon on respiratory disease (RD) hospitalisations. The aim of this studywas to determine whether the association between RD hospitalisations and air pollution in the Vaal Triangle Air Pollution Priority Areawas modified by apparent temperature (Tapp) during January 2013 to February 2020. Methods: RD admission data (ICD10 J00-J99) were obtained from two hospitals located in Vanderbijlpark and Vereeniging. AmbientPM10, PM2.5, BC, NO2, SO2 and O3, temperature and relative humidity data were obtained from six monitoring stations. A case-crossover epidemiological study design was applied. Lag0-1 was investigated, i.e. the average air pollutant level on the day and the day before hospitalisation. Models were adjusted for public holidays and Tapp. Effect modification was investigated by stratifying days into low, moderate and high Tapp days. Susceptibility by age and sex was investigated. Results: Of the 43 386 hospital admissions, 50.9% (n=22 092) were women and 51.4% (n=22 304) were 0-14-year olds. Air pollutantsexceeded the daily WHO air quality guidelines generally on more than 50% of the days. In general, moderate Tapp worsened the effects of PM2.5, PM10, SO2 and BC, whilst the effects of NO2 and O3 were most pronounced on days with high Tapp. The elderly and females were more vulnerable to air pollution, especially on days with moderate Tapp. Conclusions: These results indicate that the risk of RD hospitalisation due to ambient air pollution exposure is different on low,moderate and high Tapp days in Vanderbijlpark and Vereeniging.

Lagged acute respiratory outcomes among children related to ambient pollutant exposure in a high exposure setting in South Africa.

A school-based study was conducted using a repeated measures design, across summer and winter, in four schools in each of four suburbs in the Vaal Triangle, South Africa. Data for PM2.5, NOx, and SO2 were obtained from monitoring stations within close proximity of the schools. Over 10 school days in each phase, grade 4 children completed a symptoms log and lung function tests. Parents completed a child respiratory questionnaire. Generalized estimation equations models adjusted for covariates of interest in relation to lung function outcomes and air pollutants including lag effects of 1-5 days. Daily PM2.5, NOx, and SO2 median concentration levels were frequently higher than international standards. Among the 280 child participants (mean age 9 years), the prevalence of symptoms based on probable asthma was 9.6%. There was a consistent increased pollutant-related risk for respiratory symptoms, except for NOx and shortness of breath. Lung function, associated with pollutant fluctuations across the different lags, was most pronounced for peak expiratory flow rate (PEFR) for PM2.5 and SO2. A preceding 5-day average SO2 exposure had the largest loss (7.5 L/minute) in PEFR. Lagged declines in daily lung function and increased odds of having respiratory symptoms were related to increases in PM2.5 and SO2 among a school-based sample of children.

Integrated assessment of strategies to reduce air pollution in the Vaal Triangle Priority Area, South Africa

Integrated assessment of strategies to reduce air pollution in the Vaal Triangle Priority Area, South Africa

Developing a baseline for a tourism revitalisation strategy tailor made to a local region: The case of the Vaal Triangle region

Developing a baseline for a tourism revitalisation strategy tailor made to a local region: The case of the Vaal Triangle region

A case study in the wintertime Vaal Triangle Air-Shed Priority Area on the utility of the nitrogen stable isotopic composition of aerosol nitrate to identify NOx sources

In South Africa, the Highveld region and the Johannesburg-Pretoria megacity are known as global NOx (NOx = NO + NO2) “hotspots” identified by satellite-based instruments. The ultimate sink for atmospheric NOx is conversion to aerosol nitrate. However, measurements of aerosol nitrate concentrations do not provide information on which NOx sources served as nitrate precursors at that location. This complicates efforts to reduce concentrations of particulate matter (PM) in these air quality priority areas. Here, we measured the nitrogen stable isotopic composition of nitrate from daily wintertime collections of coarse mode PM2.5-10 (PM ≤ 10 and >2.5 µm in diameter) at three air quality monitoring stations located in the Vaal Triangle Air-Shed Priority Area (VTAPA). The overall aim of this case study was to evaluate the use of the distinct stable isotopic signatures of various NOx sources to identify their relative contribution to aerosol nitrate across the Highveld. The nitrogen isotopic ratios of aerosol nitrate were similar across the three sites, with greater day-to-day variability than site to site variability. Air mass history was the main driver of the variability in the nitrogen isotopic ratios of aerosol nitrate, with significantly higher isotopic ratios observed for air masses originating from the southwest. Using an isotope mixing model we determined that NOx from coal-burning is the dominant contributor to aerosol nitrate (66%), followed by biomass burning (16%), vehicles (12%), and soil emissions (6%).

Investment Risk Tolerance amongst South African University Students in the Vaal Triangle Area

Analysing students risk tolerance during the investor life cycle is imperative to students and financial planners alike, to facilitate the implementation of suitable investments and investment strategies. Students in universities do not have the required knowledge to invest and this is why an investment framework was created to assist, guide and inform students of what stage of the individual investor life cycle that they are in and suggest suitable investment strategies. The article implemented a quantitative approach, using secondary data analysis. The data used for the analysis is from a self-administered questionnaire in 2017 that was distributed to a sample of 396 students from two higher education institutions in the Vaal Triangle region. Two validated risk tolerance scales were used to analyse students risk tolerance levels. The objective of this paper was to determine the risk tolerance levels of students in the Vaal Triangle region. The two results from the 13-item scale and the single-item scale for measuring risk tolerance indicated that the students have a medium risk tolerance level.

The quality of the first and second Vaal Triangle Airshed Priority Area (VTAPA) Air Quality Management Plans

In response to deteriorating air quality, South Africa implemented national programmes that aim to manage and regulate ambient air quality and air pollution. Air Quality Management Plans (AQMPs) are clear outlines of measures and resources needed to achieve air quality objectives in a given geographical area and require support from government, business, industry, non-governmental organisations (NGOs) and the public. The success of the AQMPs depends primarily on the support of all stakeholders and the quality of the management plan. The Vaal Triangle Airshed Priority Area (VTAPA) was declared in 2006 as an area where ambient air quality standards are exceeded or may cause adverse air quality impacts. This research study focused on the VTAPA to evaluate the quality of the first and second-generation AQMPs for the VTAPA. Quality evaluation includes an analysis of procedures, processes, methods and documents. Effectiveness refers to the results of individual activities; therefore, the extent to which the AQMP met the expected outcomes of the review package defined the quality of the AQMP report. Both the first and draft second-generation AQMPs were considered to be of good quality. The first-generation AQMP was found to be of better quality than that of the draft second-generation AQMP. Funding mechanisms need to be investigated to assist in implementing intervention strategies in the AQMP as both the first and draft second-generation AQMPs were found to lack the potential to secure funds. Though the draft second-generation AQMP was found to be of lesser quality, the source apportionment study for identification of all sources as well as a better-outlined air quality management system was found to be good improvements to the AQMP.

Translating the Test of Academic Literacy Levels into Sesotho

This article reports on an initiative at the Vaal Triangle Campus (VTC) of North-West University (NWU) towards the active encouragement of functional multilingualism in tertiary education. More specifically, in an effort to support the potential use of Sesotho (Southern Sotho) and isiZulu in the teaching-learning environment at this campus, it was decided that an important first step should be an accurate and reliable determination of students’ levels of academic literacy (AL) in these two languages. Such a measurement would provide an indication of student readiness to make productive use of any extra learning support offered in these languages. Since there are no measuring instruments available to assess students’ academic literacy levels in Sesotho and isiZulu at tertiary level, it was decided thattranslating an existing test may be the most productive option in this case. The test selected for translation into Sesotho and isiZulu was the Test of Academic Literacy Levels (TALL), a test that has consistently shown high reliability measures in the assessment of students’academic literacy levels in English. Because Sesotho is the home language used by the majority of students (other than English and Afrikaans) at the VTC, it was decided that Sesotho would be treated as priority in terms of the completion of the project. The article therefore documents the translation process for Sesotho, and discusses primarily positive findings regarding the creation of a conceptually and functionally adequate Sesotho version of the TALL through a process of translation.

Assessing SO2, NO2 and O3 in rural areas of the North West Province

Air quality monitoring has been lacking in the rural and western North West Province. Here ambient sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) concentrations, monitored with passive samplers at 10 sites, are presented. Widespread SO2 and NO2 problems weren’t observed. However, regular O3 standard limit exceedances are likely across the province. Increased SO2 and NO2 concentrations in the colder and drier months were evident. Inversion layer trapping of low-level emissions during the colder months and open biomass burning in the drier months increased ground level pollutant concentrations. Wet deposition of SO2 and NO2, and enhanced SO2 conversion to particulate sulphate, result in lower wet season concentrations. O3 concentrations were lower from May to July and higher from August to March. Three phenomena contributed to this. Firstly, shorter daylight hours (less photochemistry) and secondly, lower biogenic volatile organic compound (O3 precursors) concentrations during the colder months. Thirdly, the late winter/early spring open biomass burning peak lead to elevated carbon monoxide (CO) concentration (also an O3 precursor). Spatial patterns indicated higher SO2 concentrations in the west, due mainly to industrial emissions. The NO2 spatial map indicated two areas of higher concentration, i.e. Bapong in the east due mainly to industrial emissions, and Taung with its higher population density. The O3 spatial map was almost the inverse of NO2. The lower O3 and higher NO2 around Taung showed that O3 is titrated there. Additionally, the results indicate that non-point source emissions of NO2 are high enough to results in exceedances of the O3 standard limit. Overlay back trajectory maps showed that sites in the east are more frequently impacted by pollution transported from the Mpumalanga Highveld, Vaal Triangle and the Johannesburg-Pretoria megacity if compared to the west. Conversely, cleaner air masses impact the west more than sites in the east.

Source apportionment of ambient PM10−2.5 and PM2.5 for the Vaal Triangle, South Africa

The Vaal Triangle Airshed Priority Area (VTAPA), like other priority areas in South Africa, has an air pollution problem. Understanding the sources contributing to air pollution in this priority area will assist in the selection and implementation of appropriate control strategies. For this study, aerosol samples in the coarse (PM10-2.5) and fine (PM2.5) fraction were collected at four sites in the VTAPA during summer/autumn, winter, and spring. The contributing sources were identified and characterised based on the elemental and ionic compositions obtained through X-ray fluorescence and ion chromatography analysis. The highest seasonal median concentrations of PM10-2.5 (116 μg/m3) and PM2.5 (88 μg/m3) were observed in Sharpeville during the winter. The lowest median concentrations of PM10-2.5 (25 μg/m3) and PM2.5 (18 μg/m3) were detected in Zamdela during the summer/autumn period. At all sites, there was a high abundance of crustal elements in PM10-2.5 and a dominance of coal and biomass combustion-related elements in PM2.5. The Positive Matrix Factorisation receptor model identified dust-related and secondary aerosols as the major contributing sources of PM10-2.5. PM2.5 contributions were predominantly from coal burning for Sebokeng and Sharpeville and from industry, wood and biomass burning, and secondary aerosols for Kliprivier and Zamdela. The results of this study identify the main sources contributing to particulate air pollution in the VTAPA and provide local authorities with valuable information for decision-making.Significance:
 
 Dust, industry, domestic coal burning, vehicles, and wood and biomass combustion are the key sources of particulate air pollution in the VTAPA that need to be prioritised by decision-makers.
 Although Sebokeng and Sharpeville are located within the vicinity of industries, domestic coal burning has a greater contribution to particulate loading at these sites.
 Results from this study will assist in the design of local municipality air quality management plans for the VTAPA.

Temperature modifies the association between air pollution and cardiovascular disease hospital admissions in the Vaal Triangle Air Pollution Priority Area, South Africa

Background: Very few studies in Africa investigated effect modification by a temperature indicator (e.g. apparent temperature, Tapp) on the human health effects of air pollution. Due to climate change, an increase of 3-4°C in ambient temperature is projected along the South African coast and 6-7°C inland during the next 80 years. Methods: Cardiovascular disease (CVD) hospital admission data (ICD10 I00-I99) were obtained from a private hospital group; after ethics approval. The study period was 1 January 2011 to 31 October 2016. NO2, SO2, PM2.5, PM10, temperature and relative humidity data were obtained from the Department of Environmental Affairs. A case-crossover epidemiological study design was applied. The present study focused on lag0-1; as most other studies. Models were adjusted for public holidays and Tapp. Days with Tapp below and above/equal the 25th (9.6°C) and 75th percentiles (20.1°C) were classified as cold and warm days, respectively. Results: Of the 15 237 admissions, 45.9% were from women and 39.0% from 15-65 year olds. The daily NO2, SO2, PM2.5 and PM10 levels were 30.3, 17.1, 35.4 and 60.8 μm/m3, respectively, and exceeded the WHO guidelines between 25% to 50% of the days. None of the air pollutants had significant associations with CVD admissions on cold or warm days. The elderly appeared to be more at risk to PM10 on normal days compared to all groups combined, e.g. RR 1.037 95%CI 1.009-1.065 per 10 μm/m3 increase compared to the unstratified analyses RR 1.017 95%CI 1.001-1.035. The same was observed for males RR 1.026 95%CI 1.003-1.050. PM2.5 had a stronger association than PM10 among the elderly on normal days: RR 1.068 95%CI 1.008-1.133. Conclusions: These results indicate that the risk of CVD admissions due to ambient air pollution exposure is different on cold, normal and warm days in Cape Town.

Temperature modifies the association between air pollution and respiratory disease mortality in Cape Town, South Africa

Background: Due to climate change, an increase of 3-4°C in ambient temperature is projected along the South African coast and 6-7°C inland during the next 80 years. Very few studies in Africa investigated effect modification by a temperature indicator (e.g. apparent temperature, Tapp) on the human health effects of air pollution. Methods: Respiratory disease (RD) mortality data (ICD10 J00-J99) were obtained from Statistics South Africa; after ethics approval. The study period was 1 January 2006 to 31 October 2015. NO2, SO2, PM10, temperature and relative humidity data were obtained from the City of Cape Town municipality. A case-crossover epidemiological study design was applied. The present study focused on lag0-1; as most other studies. Models were adjusted for public holidays and Tapp. Days with Tapp below and above/equal the 25th (12.6°C) and 75th percentiles (20.3°C) were classified as cold and warm days, respectively. Results: Of the 20376 RD deaths, approximately equal numbers were from females, males, 15-64 and 65+ year olds. The daily NO2, SO2, and PM10 levels were 16.0, 9.2, and 29.9 μm/m3, respectively. Daily air pollutant levels regularly exceeded the WHO guidelines. In general, none of the air pollutants had significant associations with RD mortality on cold days. The younger age group seemed to be more vulnerable to NO2 and PM10 on normal days compared to the elderly. On warm days, females were more susceptible to PM10, e.g. RR 1.065 95%CI 1.001-1.133 compared to the unstratified analyses RR 1.034 95%CI 0.991-1.078. On warm days, the 15-64 year old group were more vulnerable to NO2 and SO2. Conclusions: These results indicate that the risk of RD deaths due to ambient air pollution exposure is different on cold, normal and warm days in the Vaal Triangle Air Pollution Priority Area.

‘Our Bushes Are the Houses’: People’s War and the Underground during the Insurrectionary Period in the Vaal Triangle, South Africa

The insurrectionary period in South Africa from 1984 to 1986 saw thousands of young and old people confronting the apartheid regime in the streets, the workplace and elsewhere. The revolts were largely led by a broad coalition from below. While the African National Congress (ANC) provided ideological and symbolic guidance, its organisational capacity was limited. In the aftermath of the National Consultative Conference in Kabwe, Zambia, in June 1985, the ANC accelerated its effort to promote a people’s war, which regarded the arming and training of domestic units under the guidance of cadres of Umkhonto weSizwe (MK), and the mobilisation of the local population, as essential. Yet, on the ground, many of the militarised youth groups who were fighting the police and soldiers in the name of people’s war remained outside the direct control of the ANC’s leadership. They broadly followed the ideological and strategic programme of the ANC and, in some instances, received weapons and rudimentary military training. Based on ethnographic fieldwork, oral history interviews and archival research, this article traces the experiences and motivations of one such group in the township of Sebokeng to the south of Johannesburg. It focuses on the complex relationships between popular insurgency and the ANC’s call for people’s war and ungovernability. The article argues that a lack of control and support not only gave these units considerable freedom to interpret the ANC’s strategic objectives, but it also created issues of accountability and exposed them to risks due to poor training and discipline.

Evaluating the potential of remote sensing imagery in mapping ground-level fine particulate matter (PM2.5) for the Vaal Triangle Priority Area

The quality of air breathed in South Africa is of great concern, especially in industrialised regions where PM2.5 concentrations are high. Long term exposure to PM2.5 is associated with serious adverse health impacts. Traditionally, PM2.5 is monitored by a network of ground-based instruments. However, the coverage of monitoring networks in South Africa is not dense enough to fully capture the spatial variability of PM2.5 concentrations. This study explored whether satellite remote sensing could offer a viable alternative to ground-based monitoring. Using an eight-year record (2009 to 2016) of satellite retrievals (MODIS, MISR and SeaWIFS) for PM2.5 concentrations, spatial variations and temporal trends for PM2.5 are evaluated for the Vaal Triangle Airshed Priority Area (VTAPA). Results are compared to corresponding measurements from the VTAPA surface monitoring stations. High PM2.5 concentrations were clustered around the centre and towards the south-west of the VTAPA over the highly industrialised cities of Vanderbijlpark and Sasolburg. Satellite retrievals tended to overestimate PM2.5 concentrations. Overall, there was a poor spatial agreement between satellite-retrieved PM2.5 estimates and ground-level PM2.5 measurements. Root mean square error values ranged from 6 to 11 µg/m3 and from -0.89 to 0.32 for the correlation coefficient. For satellite remote sensing to be effectively exploited for air quality assessments in the VTAPA and elsewhere, further research to improve the precision and accuracy of satellite-retrieved PM2.5 is required.

The influence of strategic networks and logistics integration on firm performance among small and medium enterprises

Background: In order to stay competitive in business and improve performance, small and medium enterprises (SMEs) need to make use of business networking and logistics integration. Strategic networking and logistics integration in business have become critical as they allow supplier partnering, exchange of vital information or access to valuable resources allowing innovation, gaining access to additional resources, sharing risks and costs, which is required for enhancing firm performance. Strategic networks and logistics integration across partnering firms have therefore become paramount to supply chain management as they are critical to firm performance. Most studies in this subject matter have focussed on larger firms. It became imperative for this study to focus on SMEs. Objectives: The purpose of this study was to examine the influence of strategic networks and logistics integration on firm performance in SMEs in the Vaal Triangle. Method: A quantitative research design was adopted in this study. The owners and managers of 137 SMEs completed the survey questionnaire. Confirmatory factor analysis (CFA) was conducted to assess the psychometric properties of the measurement scales. Path modelling techniques were used to test the proposed hypotheses. Results: The results indicate that strategic networks had a positive and significant influence on logistics integration and firm performance. Furthermore, logistics integration had a strong positive and significant influence on firm performance. Conclusion: This study sheds light on the possibility of enhancing the overall performance of SMEs by establishing and empirically testing the relationships between logistics integration and strategic networks and firm performance. Moreover, the findings of the study provide useful insights into how SMEs should benefit from business networking and logistics integration to improve their performance.

Assessment of changes in concentrations of selected criteria pollutants in the Vaal and Highveld Priority Areas

Ambient air pollution has important impacts on a variety of environmental issues, particularly on human health and ecosystem processes. A key tool for understanding the impacts of atmospheric pollution is through the long term measurement of the ambient concentrations of criteria atmospheric pollutants. Monitoring of ambient pollution concentrations has been conducted in the National Air Quality Priority areas since 2009. During this time period, significant changes in the management of air pollution have occurred, including the adoption of the ambient air quality standards, and the implementation of section 21 emission standards. This paper examines the long term evolution of ambient concentrations for PM, SO2 in the Vaal Triangle Airshed Priority Area 2007-2017 and Highveld Priority Area. These trends will be evaluated against the implementation of management interventions and highlight the variation in the measured concentrations and emerging areas of concern.

Temporal and source assessments of organic and elemental carbon at sites in the northern South African interior

Particulate matter (PM) can affect climate, air quality, human health, acid deposition and visibility, and contain a significant fraction of organic (OC) and elemental carbon (EC). Southern Africa is an important source region for OC and EC, however, little OC and EC data have been published for this region. This paper presents a multi-year, multi-site (an urban-industrial site in the Vaal Triangle, UI-VT; an industrially influenced site at Amerfoort, iI-AF; and two regional background sites at Skukuza and Louis Trichardt, RR-SK and RR-LT) PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5) OC and EC dataset for South Africa. The median OC (9.3) and EC (3.2 μg.m−3) concentrations at UI-VT were 1.3 to 2.5 and 2.7 to 4.4 times higher, if compared to the other sites. OC/EC ratios indicated that sources in close proximity to UI-VT were likely the main contributors, while sources that are more distant contributed fractionally more at the other sites. Household combustion for space heating and regional open biomass burning contributed to elevated levels during the cold and dry months at UI-VT. Regional open biomass burning also lead to higher OC and EC concentrations during the dry season at the industrially influenced site (iI-AF) and one of the regional background sites (RR-SK). From the seasonal concentration patterns, it seemed as if household combustion for space heating also contributed at these two sites during the cold months, but this could not be proven, even if only samples with limited influence of open biomass burning were considered. Such biomass burning influences were semi-quantified by considering MODIS fire pixels occurring within the air mass fetch region for each sample. For the remaining regional background site (RR-LT) the results suggesed that only regional open biomass burning contributed to elevated levels of OC and EC in the dry season and that household combustion for space heating did not contribute significantly.