A5006242415- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Air Quality Monitoring and Forecasting
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Climate variability and models
- Plant Water Relations and Carbon Dynamics
- Vehicle emissions and performance
- Hydrology and Watershed Management Studies
- Heavy metals in environment
- Energy and Environment Impacts
- Radioactivity and Radon Measurements
- Plant responses to elevated CO2
- Meteorological Phenomena and Simulations
- Environmental and Agricultural Sciences
- Geochemistry and Geologic Mapping
- COVID-19 impact on air quality
- Tree-ring climate responses
- Soil Geostatistics and Mapping
- Chromium effects and bioremediation
- Wind and Air Flow Studies
- Environmental and Industrial Safety
- Soil Moisture and Remote Sensing
- Mining and Resource Management
North-West University
2016-2025
University of Johannesburg
2009-2011
Abstract. In this paper we describe and summarize the main achievements of European Aerosol Cloud Climate Air Quality Interactions project (EUCAARI). EUCAARI started on 1 January 2007 ended 31 December 2010 leaving a rich legacy including: (a) comprehensive database with year observations physical, chemical optical properties aerosol particles over Europe, (b) measurements in four developing countries, (c) airborne aerosols clouds Europe during May 2008, (d) modeling tools to study processes...
Primary and secondary aerosol particles originating from biomass burning contribute significantly to the atmospheric budget thereby both direct indirect radiative forcing. Based on detailed measurements of a large number plumes variable age in southern Africa, we show that size distribution, chemical composition, single-scattering albedo, hygroscopicity change considerably during first 2–4 h their transport. These changes, driven by oxidation subsequent formation, may reach factor 6 for...
Abstract. Combustion of fuels in the residential sector for cooking and heating results emission aerosol precursors impacting air quality, human health, climate. Residential emissions are dominated by combustion solid fuels. We use a global microphysics model to simulate impact fuel on atmospheric year 2000. The underestimates black carbon (BC) organic (OC) mass concentrations observed over Asia, Eastern Europe, Africa, with better prediction when carbonaceous from doubled. Observed seasonal...
South Africa has the largest industrialised economy in Africa, with significant mining and metallurgical activities. A large fraction of African mineral assets is concentrated Bushveld Igneous Complex (BIC), western limb being most exploited. Because majority world's platinum produced BIC, this area also international interest. There are some indications that BIC should be considered an air pollution hotspot; however, inadequate data exist to substantiate these claims scientifically. To...
Abstract. Southern Africa is a significant source region of atmospheric pollution, yet long-term data on pollutant concentrations and properties from this are rather limited. A recently established measurement station in South Africa, Welgegund, strategically situated to capture regional background concentrations, as well emissions the major regions interior Africa. We measured non-refractive submicron aerosols (NR-PM1) black carbon over one year period investigated seasonal diurnal patterns...
Abstract. The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon (BC) measurements. In this paper, we show correction methods an artifact found to affect the accuracy in environments characterized by high concentrations. occurs after filter spot change – as BC mass accumulated on fresh spot, attenuation of light (raw signal) weaker than anticipated. This causes sudden decrease, followed gradual increase measured concentration. present data when...
Abstract. Atmospheric lidar measurements were carried out at Elandsfontein measurement station, on the eastern Highveld approximately 150 km east of Johannesburg in South Africa throughout 2010. The height planetary boundary layer (PBL) top was continuously measured using a Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended). High atmospheric variability together with large surface temperature range and significant seasonal changes precipitation observed, which had an impact vertical...
Abstract. In this paper we introduce new in situ observations of atmospheric aerosols, especially chemical composition, physical and optical properties, on the eastern brink heavily polluted Highveld area South Africa. During observation period between 11 February 2009 31 January 2011, mean particle number concentration (size range 10–840 nm) was 6310 cm3 estimated volume sub-10 μm particles 9.3 μm3 m−3. The aerosol absorption scattering coefficients at 637 nm were 8.3 Mm−1 49.5 Mm−1,...
Abstract. Aromatic hydrocarbons are associated with direct adverse human health effects and can have negative impacts on ecosystems due to their toxicity, as well indirect through the formation of tropospheric ozone secondary organic aerosol, which affect health, crop production regional climate. Measurements aromatic were conducted at Welgegund measurement station (South Africa), is considered be a regionally representative background site. However, site occasionally impacted by plumes from...
Abstract. Atmospheric trace metals can cause a variety of health-related and environmental problems. Only few studies on atmospheric metal concentrations have been conducted in South Africa. Therefore the aim this study was to determine aerosols collected at regional background site, i.e. Welgegund, PM1, PM1–2. 5 PM2. 5–10 samples were for 13 months, 31 species detected. iron (Fe) had highest all three size fractions, while calcium (Ca) second-most-abundant species. Chromium (Cr) sodium (Na)...
Abstract. Biogenic volatile organic compounds (BVOCs) play an important role in the chemistry of troposphere, especially formation tropospheric ozone (O3) and secondary aerosols (SOA). Ecosystems produce emit a large number BVOCs. It is estimated on global scale that approximately 90 % annual BVOC emissions are from terrestrial sources. In this study, measurements BVOCs were conducted at Welgegund measurement station (South Africa), which considered to be regionally representative background...
Abstract. Tropical savannas and grasslands are estimated to contribute significantly the total primary production of all terrestrial vegetation. Large parts African used for agriculture cattle grazing, but carbon flux data available from these areas limited. This study explores dioxide fluxes measured with eddy covariance method 3 years at a grazed savanna grassland in Welgegund, South Africa. The tree cover around measurement site, by sheep, was 15 %. night-time respiration not dependent on...
This study evaluates the Mercury Passive Air Sampler ( Mer PAS®) as a cost-effective alternative to active sampling for atmospheric mercury monitoring at Welgegund measurement station in South Africa.
We tested the hypothesis that acidic atmospheric pollution deposition, originating from South African central industrial area, poses an environmental threat across a larger region within dispersal footprint. A network of 37 passive monitoring sites to measure SO2 and NO2 was operated August 2005 September 2007. The area extended over entire northern eastern interior Africa. Monitoring locations were chosen avoid direct impacts local sources such as towns, mines highways. Dry deposition rates...
Abstract. After carbon dioxide (CO2), aerosol black (BC) is considered to be the second most important contributor global warming. This paper presents equivalent (eBC) (derived from an optical absorption method) data collected three sites in interior of South Africa where continuous measurements were conducted, i.e. Elandsfontein, Welgegund and Marikana, as well elemental (EC) (determined by evolved at five samples once a month on filter analysed offline, Louis Trichardt, Skukuza, Vaal...
Abstract. Although elevated surface ozone (O3) concentrations are observed in many areas within southern Africa, few studies have investigated the regional atmospheric chemistry and dominant processes driving O3 formation this region. Therefore, an assessment of comprehensive continuous measurements performed at four sites continental South Africa was conducted. The problem evident, with regularly exceeding African air quality standard limit, while levels were higher compared to other...
Abstract. South Africa has one of the largest industrialized economies in Africa. Emissions air pollutants are particularly high Johannesburg-Pretoria metropolitan area, Mpumalanga Highveld and Vaal Triangle, resulting local pollution. This study presents evaluates a setup for conducting modeling experiments over southern with Weather Research Forecasting model including chemistry aerosols (WRF-Chem), analyzes contribution anthropogenic emissions to total black carbon (BC) concentrations...
Abstract Aerosol particles formed in the atmosphere are important to Earth's climate system due their ability affect cloud properties. At present, little is known about atmospheric chemistry responsible for growth of newly aerosol climate‐relevant sizes. Here combining detailed measurements with a theoretical framework we found that depending on gaseous precursors and size particles, was dominated by either sulfuric acid accompanied ammonium or organic compounds originating biogenic...
Abstract. Raman lidar data obtained over a 1 year period has been analysed in relation to aerosol layers the free troposphere Highveld South Africa. In total, 375 were observed above boundary layer during 30 January 2010 31 2011. The seasonal behaviour of geometrical characteristics, as well intensive and extensive optical properties studied. highest centre heights free-tropospheric African spring (2520 ± 970 m a.g.l., also elsewhere). depth was found be maximum spring, while it did not show...
Abstract The main source of soil moisture variability in savanna ecosystems is pulsed rainfall. Rainfall pulsing impacts water‐stress durations, switching between wet‐to‐dry and dry‐to‐wet states, spectra as well derived measures from it such memory. also responsible for rapid changes grassland leaf area concomitant evapotranspirational (ET) losses, which then impact variability. With the use a hierarchy models measurements, temporal root‐zone periods are analysed at four African sites...
Abstract The Pandora spectrometer that uses direct‐Sun measurements to derive total column amounts of gases provides an approach for (1) validation satellite instruments and (2) monitoring (TC) ozone (O 3 ) nitrogen dioxide (NO 2 ). We use the first time Ozone Monitoring Instrument (OMI) observations estimate surface NO over marine terrestrial sites downwind urban pollution compared with in situ during campaigns contrasting regions: South African Highveld (at Welgegund, 26°34′10″S,...