Stuart J. Piketh

• PhD
• Professor (Full) at North-West University

This study investigated the chemical composition and shortwave absorption coefficient, βabs(λ), of aerosols collected from sites on the Highveld, a major industrial and highly polluted region of South Africa. Local anthropogenic mineral dust was found to be the dominant chemical component, accounting for (53 ± 14)% of the aerosol mass concentration...

Background: Data on allergic rhinitis and respiratory health metrics are limited for South Africa, with grass pollen as a key outdoor aeroallergen. Exotic trees such as plane trees and ragweed produce highly allergenic pollen, dominating indigenous trees and weeds. Pollen allergy prevalence data is lacking in cities of North-West province such as P...

This paper presents the results of three weeks of aerosol sampling at the Henties Bay coastal site in Namibia during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) field campaign in August–September 2017. The campaign coincided with a transition period between two synoptic regimes and corresponded to a significant change in the...

Coal combustion in coal-fired power plants is the dominant source of mercury (Hg) emissions in South Africa. The majority of these plants are located in the South African Highveld, an area that experiences poor air quality. Despite this, the specifics of Hg emissions – such as the amounts emitted, mercury species emitted and their spatial variabili...

Most major field campaigns, such as the Southern Africa Fire Atmosphere Research Initiative (SAFARI-92 and SAFARI-2000) and AErosol, RadiatiOn and CLOuds in southern Africa (AEROCLO-sA), have focused on the west coast of southern Africa, leaving the east coast underexplored. To address this, the Biomass Burning Aerosol Campaign (BiBAC) was initiate...

Urban green spaces (UGS), such as parks, gardens, and trees, are essential in urban areas, providing ecosystem services (ES) that support human well-being and environmental health. Urban trees are particularly effective in improving air quality, regulating climate, and reducing dust, services that are especially critical in the Global South, where...

This research used descriptive statistics to analyse rainfall trends in the Cuvelai- Etosha Basin (Namibia) over a 50-year historical period (1968 to 2018). The results revealed that rainfall fell over a period of 6 months between the months of November and April. Rainfall amounts were also observed to be higher in the first 3 months of each year,...

This pioneering study evaluates the prevalence of aeroallergens reactivity among atopic populations living in the Vaal Triangle Airshed Priority Area (VTAPA), South Africa. A total of 138 volunteers (51 males and 87 females), of African, colored, white, and Asian ethnicity, and with a mean (range) age of 22 (18–56) years were participating in the s...

The Benguela upwelling system (BUS) is frequently subject to dust deposition from southern Africa, which supplies macronutrients and trace metals to the ocean. The impact of these nutrients on chlorophyll-a (Chl-a) in the BUS was investigated using the first-ever mesocosm study from 29 September to October 12, 2022. The study employed a single trip...

The west coast of southern Africa is a region of particular climate interest and a crossroad for aerosols of different origins as well as fog occurrences. In this study, we present a comparison between the solubility of trace metals in pairs of total suspended particulate (TSP) and fog water samples collected in Henties Bay, Namibia, during the AEr...

Landfill gas (LFG) emissions, primarily CH4 and CO2, result from decomposing organic waste in landfills. South Africa faces challenges in managing LFG emissions and effectively handling landfill sites. For this study, a static flux chamber was used to sample CH4 and CO2 emissions. The study showed that CH4 emissions in the capped area had a concent...

Health-related impacts e.g. respiratory and cardiovascular morbidity and mortality, associated with exposure to atmospheric particulate matter (PM) are globally considered important and are not completely understood. Oxidative potential (OP), defined as a measure of the capacity of PM to oxidise target molecules, has been previously proposed as an...

International reports have documented a positive correlation between allergic symptoms and pollen abundance. In South Africa, the burden of allergic respiratory disease is substantial. 13.7% overall prevalence of severe asthma among adolescents, and more than 30% of our adult population suffers from allergic rhinitis. Grass pollen, house-dust mites...

Coal power stations in Mpumalanga and Limpopo are the largest emitters of SO2 in South Africa. This study investigates the meteorological factors associated with severe SO₂ events at the Majuba power station between January 2015 and March 2020. Historical SO₂ data was analysed to identify four days with peak concentrations, focusing only on days wi...

Nitrogen oxides, particularly NO2, are emitted through a variety of industrial and transport processes globally. The world’s continuous economic development, including in developing countries, results in an increasing concentration of those gases in the atmosphere. Yet, there is scant information on the current state and recent evolution of these a...

A Low-cost sensors for particulate matter can provide high spatiotemporal resolution monitoring of air quality, especially in much of the Global South, and sub-Saharan Africa (SSA) in particular, where reference-grade instrumentation is often not available. However, ensuring high-quality data from low-cost sensor (LCS) platforms is essential. Until...

This paper provides an overview of the HEAT (Healthy Environments for AthleTes) project, which aims to understand the impact of environmental conditions on athlete health and performance during major sporting events such as long-distance running, cycling, and triathlons. In collaboration with the SAFER (Strategies to Reduce Adverse Medical Events F...

This case study presents the evolution of aerosol optical properties during Intensive Observational Period (IOP) of the Biomass Burning Aerosol Campaign (BiBAC) in the Kruger National Park at Skukuza, between 18 and 23 September (Event 1) and 9 and 17 October (Event 2) 2022. The aerosol classification from sun-photometer data is consistent with the...

Globally, particulate matter with an aerodynamic diameter of 2.5 μm or less poses a significant threat to human health. The first step in quantifying human health impacts caused by exposure to PM2.5 pollution is exposure assessment. Population-weighted exposure level (PWEL) estimation is one of the methods that provides a more precise exposure asse...

This paper presents the first investigation of the solubility of iron in mineral dust aerosols collected at the Henties Bay Aerosol Observatory (HBAO), in Namibia, from April to December 2017. During the study period, 10 intense dust events occurred. Elemental iron reached peak concentrations as high as 1.5 µg m-3, significantly higher than backgro...

This paper aims to study the interconnection between aerospora and environmental conditions in the city of Potchefstroom, in South Africa.

We value comments on our research paper in a Commentary in this issue (Simpson, S Afr J Sci. 2024;120(1/2), Art. #16445). Acknowledging the Universal Thermal Comfort Index (UTCI)'s limitations in capturing individual physiological responses remains important; however, we argue for its appropriateness based on recent thermophysiology and heat exchan...

Data on respiratory syncytial virus (RSV) incidence and household transmission are limited. To describe RSV incidence and transmission, we conducted a prospective cohort study in rural and urban communities in South Africa over two seasons during 2017-2018. Nasopharyngeal swabs were collected twice-weekly for 10 months annually and tested for RSV u...

Air pollution is an environmental risk factor to human health globally. Exposure to ambient fine particulate matter (PM2.5) is a major health challenge around the world, due to its minute size and potency to penetrate through the lungs into the circulatory system where its detrimental effect is felt. While some of the developed countries have we...

The widespread exposure to ambient PM 2.5 poses a substantial health risk globally, with a more pronounced impact on low- to medium-income nations. This study investigates the spatiotemporal distribution of PM 2.5 in the communities hosting informal brickmaking industries in Vhembe District. Utilizing Dylos DC1700, continuous monitoring of PM 2.5 w...

About 70% of the roads in low-income settlements are unpaved and close (≤15m) to residents, thus a major source of ambientand indoor PM10 concentrations. International studies have suggested that decreasing vehicle speed and managing vehicle type onpaved or unpaved roads can reduce vehicle dust emissions. These mitigation strategies should be exami...

In southern Africa, notable dust-emitting sources play a significant role in the region’s atmospheric and ecological dynamics. This study revisits the recognised sources and identifies six new potential sources in southwestern Angola (AS) and their dust emissions between January 2016 and December 2017. The study utilised a multisensory approach com...

The Namibian coast is one of the areas of international interest for aerosol studies. This is due to the region’s importance for the global radiation budget because of the presence of a semi-permanent stratocumulus cloud along the coast. Aerosol particles may scatter/absorb radiation and directly influence how long clouds last by modifying their pr...

Exposure to airborne pollen and fungal spores is a major health concern during outdoor sporting events and poses a risk to large numbers of athletes who may suffer an allergic response.This study forms part of a larger field campaign introducing Healthy Environments for Athletes (HEAT) and appropriate strategies to reduce adverse medical incidents...

Biomass Burning Emission in South Africa

Mineral dust is the largest contributor to elemental iron in the atmosphere, and, by deposition, to the oceans, where elemental iron is the main limiting nutrient. Southern Africa is an important source at the regional scale, and for the Southern Ocean, however limited knowledge is currently available about the fractional solubility of iron from th...

Water scarcity due to rainfall variability, and exacerbated by climate change, is prevalent in many regions of the world. Lack of precipitation and excessive water extraction contribute to the intensification of the problem. Among different mitigation measures, rain enhancement through cloud seeding could be a tool as part of a water management str...

The government-accredited GA 2000 landfill gas analyzer was used to monitor the landfill gas (methane (CH4) and carbon dioxide (CO2)) generated from the subsurface of a landfill. Eighteen gas sample probes were constructed and placed approximately 100 m apart on the boundaries of the landfill site. The monitoring of the gases was conducted over a p...

Fires occur seasonally in Southern Africa, from June to November, increasing tropospheric aerosol loading and triggering harmful consequences for the environment and human health. This study aims to examine 13 years of aerosol optical characteristics and types over Southern Africa and Reunion Island. Using AERONET sun photometers and MODIS observat...

The paper introduces the Healthy Environments for Athletes field campaign to measure environmental conditions (heat stress and allergenic agents) associated with endurance events.

This paper presents the first approach for monitoring atmospheric pollen and fungal spores during an outdoor sports event, here the Comrades Marathon 2022. This study is associated with a larger field campaign project introducing Healthy Environments for Athletes (HEAT) and appropriate strategies to reduce adverse medical incidents at endurance eve...

South Africa currently faces a serious problem of air pollution in its cities. The approach used to manage air quality has not yet met the desired outcomes. In this study, potential mitigation options for ambient PM2.5 in the Vaal Triangle Airshed Priority Area (VTAPA)—one of the most industrialised regions in South Africa—were explored using the G...

Naturally and anthropogenically emitted aerosols, which are determined by their physical and chemical properties, have an impact on both air quality and the radiative properties of the earth. An important source of atmospheric particulate matter (PM) in South Africa is household combustion for space heating and cooking, which predominantly occurs i...

Aerosol-aware microphysics parameterisation schemes are increasingly being introduced into numerical weather prediction models, allowing for regional and case-specific parameterisation of cloud condensation nuclei (CCN) and cloud droplet interactions. In this paper, the Thompson aerosol-aware microphysics scheme, within the Weather Research and For...

The Comrades Marathon is South Africa’s – and the world’s – most recognised and largest ultra-marathon event, with over 15 000 participants from across the globe competing in the 89-km road running event each year. Historically, the event has been held before the start of austral winter (20 May – 17 June). However, in 2022, organisers of the race m...

South Africa is the largest national source of industrial atmospheric pollutants in Africa, and the emission of acid-forming pollutants occurs mainly in the eastern Highveld region of the country. However, spatial information on deposition is very sparse beyond the primary emissions zone. Here we quantify wet and dry deposition at four sites from t...

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 ser...

Anthropogenic emissions from industry, biomass burning and traffic are significant contributors to the atmospheric loading of nitrogen dioxide on the South African Highveld. These sources are dispersed across the region and emit nitrogen oxides (NO and NO2) into the atmosphere at different elevations above the earth's surface. Additionally, atmosph...

Marine ecosystems are important drivers of the global climate system. They emit volatile species into the atmosphere, involved in complex reaction cycles that influence the lifetime of greenhouse gases. Sea spray and marine biogenic aerosols affect Earth's climate by scattering solar radiation and controlling cloud microphysical properties. Here we...

The formation of a river of smoke crossing southern Africa was investigated during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) campaign in September 2017. A complementary set of global and mesoscale numerical simulations as well as ground-based, airborne and space-borne observations of the dynamics, thermodynamics and composi...

Aerosol aware microphysics parameterisation schemes are increasingly being introduced into numerical weather prediction models, allowing for regional and case specific parameterisation of cloud condensation nuclei (CCN) and cloud droplet interactions. In this paper, the Thompson aerosol aware microphysics scheme, within the Weather, Research and Fo...

Naturally and anthropogenically emitted aerosols, which are determined by their physical and chemical properties, have an impact on both air quality and the radiative properties of the earth. An important source of atmospheric particulate matter (PM) in South Africa is household combustion for space heating and cooking, which predominantly occurs i...

Emissions from residential solid fuels reduce ambient air quality and cause indoor air pollution resulting in adverse human health. The traditional solid fuels used for cooking include coal, straws, dung, and wood, with the latter identified as the prevalent energy source in developing countries. Emissions from such fuel sources appear to be signif...

This commentary paper from the recently formed International Global Atmospheric Chemistry (IGAC) Southern Hemisphere Working Group outlines key issues in atmospheric composition research that particularly impact the Southern Hemisphere. In this article, we present a broad overview of many of the challenges for understanding atmospheric chemistry in...

The South African Highveld is recognised as a region having significant negative ambient air quality impacts with its declaration as an Air Quality Priority Area in 2007. Such areas require the implementation of specific air quality intervention strategies to address the air quality situation. A greater understanding of the composition of the atmos...

This global study, which has been coordinated by the World Meteorological Organization Global Atmospheric Watch (WMO/GAW) programme, aims to understand the behaviour of key air pollutant species during the COVID-19 pandemic period of exceptionally low emissions across the globe. We investigated the effects of the differences in both emissions and r...

The World health organization (WHO) is particularly concerned about the ambient concentrations of Particulate Matter (PM10, PM2.5), Sulphur dioxide (SO2), Nitrogen dioxide (NO2), and Ozone (O3). This paper investigates the contributions of both the coal-fired plants and the coal-burning households to these critical pollutants. Using twelve months’...

The formation of a river of smoke crossing southern Africa is investigated during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) campaign in September 2017. A complementary set of global and mesoscale numerical simulations as well as ground-based, airborne and space-borne observations of the dynamics, thermodynamics and composit...

Emissions from residential solid fuel burning in densely populated low-income settlements is a significant source of air pollution over the South African Highveld. The area is densely populated and highly industrialized, resulting in high concentrations of pollutants over the area. Although emissions from industrial sources are much larger, exposur...

Understanding how exposure to particulate matter impacts human health is complex. Personal exposure is a function of the pollution concentrations measured at any given place and time. The health impacts of this exposure are, amongst other factors, determined by how high pollutant concentrations are and what enters the body. This study considered da...

The study aims to assess the air quality status of Thulamela municipality in the Vhembe District of Limpopo using Dylos DC1700. The PM2.5 concentrations of the ambient environment and the diurnal and daily variability of PM2.5 concentrations with changes in meteorological factors were monitored between February and April 2021. The results showed hi...

Vehicle emissions are a major source of air pollution in Thulamela Municipality, Limpopo Province, South Africa. The province is currently experiencing an inflow of people from villages, which increases the human population, the number of vehicles, and vehicle kilometres traveled (VKT). However, there is a lack of baseline data on vehicle emission...

The brick making industry, despite its contribution to environmental pollution, plays a major role in the economic growth of South Africa, with the traditional technology accounting for a significant proportion of the total clay brick production. The aim of this study is to undertake a comprehensive description of the production phases of the tradi...

We currently have a limited understanding of the spatial and temporal variability in vertically stratified atmospheric layers over Namibia and the southeast Atlantic (SEA) Ocean. Stratified layers are relevant to the transport and dilution of local and long-range transported atmospheric constituents. This study used eleven years of global positioni...

Purpose The PHIRST study (Prospective Household cohort study of Influenza, Respiratory Syncytial virus, and other respiratory pathogens community burden and Transmission dynamics in South Africa) aimed to estimate the community burden of influenza and respiratory syncytial virus (RSV) including the incidence of infection, symptomatic fraction, and...

Abstract Background Describing contact patterns is crucial to understanding infectious disease transmission dynamics and guiding targeted transmission mitigation interventions. Data on contact patterns in Africa, especially South Africa, are limited. We measured and compared contact patterns in a rural and urban community, South Africa. We assessed...

Background Data on influenza community burden and transmission are important to plan interventions especially in resource-limited settings. However, data are limited, particularly from low-income and middle-income countries. We aimed to evaluate the community burden and transmission of influenza in a rural and an urban setting in South Africa. Met...

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 (...

High concentrations of the ambient particulate matter remain a concern on the South African Highveld, particularly in densely populated low-income settlements. These areas have several local emission sources that contribute to poor air quality and are often located close to industrial and other urban areas. The local sources vary in magnitude, spac...

High concentrations of the ambient particulate matter remains a concern on the South African Highveld, particularly in densely populated low-income settlements. These areas have several local emission sources that contribute to poor air quality and are often located close to industrial and other urban areas. The local sources vary in magnitude, spa...

Domestic solid fuel combustion remains a key contributor to indoor and ambient air pollution in low-income settlements. Understanding solid-fuel cost perceptions and burning patterns variability is required for developing sustainable energy policies and applicable site-specific intervention strategies to effectively improve ambient air quality. The...

A reliable fog forecast can assist in water resource management and mitigate against hazardous effects on transport networks. However, diagnosing fog from numerical weather prediction models remains a challenge and various methods have been developed to achieve this. One approach is to use a multi rule-based method, where threshold values of multip...

During 2016 to 2018, a prospective household cohort study of influenza and respiratory syncytial virus community burden and transmission dynamics (the PHIRST study) was undertaken to examine the factors associated with influenza and other respiratory pathogen transmissions in South Africa. We collected information on housing conditions in the PHIRS...

Southern Africa produces almost a third of the Earth's biomass burning (BB) aerosol particles, yet the fate of these particles and their influence on regional and global climate is poorly understood. ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) is a 5-year NASA EVS-2 (Earth Venture Suborbital-2) investigation with three in...

Fog has a significant effect on aviation and road transport networks around the world. The International Airport in Abu Dhabi, United Arab Emirates, experiences dense fog during winter months that affect operations at the airport. We describe the fog climatology at the airport using 36 years of Meteorological Aerodrome Reports (METAR), an important...

Purpose The PHIRST study (Prospective Household cohort study of Influenza, Respiratory Syncytial virus, and other respiratory pathogens community burden and Transmission dynamics in South Africa) aimed to estimate the community burden of influenza and respiratory syncytial virus (RSV) including the incidence of infection, symptomatic fraction, and...