Effluents from the paint industry have been a major source of environmental pollution. There is a need to investigate the compliance of wastewater discharged from paint industries with regulatory standards. In response, this study evaluates the physicochemical parameters of both raw and treated wastewater, the wastewater treatment plants (WWTPs) efficiencies as well as the compliance level of five selected paint manufacturing companies in Lagos, Nigeria with some regulatory standards: Federal Ministry of Environment (FME) in Nigeria, World Health Organization (WHO) and Department of Water Affairs (DWA) in South Africa. All parameters investigated were analysed using standard methods. The values of pH, electrical conductivity (EC) and total dissolved solids (TDS) levels were in the range of 4–12.2, 149.1–881.3 mS/m and 1100–6510 mg/L, respectively. The range of other parameters include total suspended solids (TSS); 0–2470 mg/L, TS; 1920–6510 mg/L, chloride; 63.8–733.8 mg/L, dissolved oxygen (DO); 0–6.7 mg/L, oil and grease (O & G); 44–100 mg/L, biochemical oxygen demand (BOD); 162.8–974.7 mg/L, chemical oxygen demand (COD); 543–1231 mg/L, nitrates;12.89–211.2 mg/L, phosphate; below detection limit (bdl)–0.02 mg/L, sulphate; 195–1434 mg/L, nickel; bdl–1.9 mg/L while copper, lead and chromium were below detection limits. The results indicated that the WWTPs of the studied paint companies were ineffective in reducing the TS, TSS, BOD, COD and (O & G) to acceptable limits. Routine monitoring of wastewater from paint industries is therefore recommended to prevent the risk of contamination to the receiving watershed which many communities rely on as source for domestic water.

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 traditional brick making sector in Vhembe district and how this contributes to air pollution. The study comprised a series of interviews and questionnaires of key role players from two small villages, Manini and Tshilungoma in the Vhembe district. In-situ observations of the production methods and phases were also undertaken between June and December 2019. The brick making production phases used in Vhembe district are excavation, preparation, moulding, drying and firing. An average estimate of 34,683 bricks is fired monthly per brick kiln in Vhembe district. Emissions from brick making organisations had resulted into several public health and environmental risks. To reduce environmental degradation, the incorporation of industrial and environmental wastes into brick making and the gradual transition to environmentally friendly technology such as Vertical Shaft brick kiln (VSBK) should be embraced. Thus, traditional brick making implemented with appropriate sustainable environmental technology has the potential to improve the socio-economic status of the brick makers.

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 was conducted at nine stations adjacent to informal brick kilns from March 2021 to February 2022. The study determined the correction factor for PM_2.5 measurements obtained from the Dylos DC1700 when it was collocated with the GRIMM Environmental Dust Monitor 180. Additionally, the diurnal and seasonal variations across monitoring stations were assessed, and potential PM_2.5 sources were identified. The study also evaluated the compliance of ambient PM_2.5 concentrations across the stations with the South African National Ambient Air Quality Standard (NAAQS) limits. Annual PM_2.5 concentrations for the stations ranged from 22.6 to 36.2 μgm⁻³. Diurnal patterns exhibited peak concentrations in the morning and evening, while seasonal variations showed higher concentrations in winter and lower concentrations in summer and spring. All monitoring stations reported the highest daily exceedance with respect to the daily NAAQS limit in the winter. Major PM_2.5 sources included domestic biomass combustion, vehicular emissions, industrial emissions, and construction sites. Well-calibrated low-cost sensors could be employed in suburb regions with scarce air quality data. Findings from the study could be used for developing mitigation strategies to reduce health risks associated with PM_2.5 exposure in the area.

Globally, particulate matter with an aerodynamic diameter of 2.5 mu m 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 assessment since it incorporates the spatiotemporal distribution of population with the pollution concentration estimate. In this study, PM2.5 exposure levels in the local communities around brickmaking industries were investigated, using the population census data of the study area and 1-year data from nine PM2.5 monitoring stations installed in and around the brickmaking industries. The observed PM2.5 data was spatially interpolated using inverse distance weight (IDW). Data on PM2.5 levels across the study area were classified based on the World Health Organization interim target (IT) guidelines and the South African National ambient air quality standard (NAAQS). An annual PM2.5 population weighted exposure level of 27.6 mu g/m(3) was estimated for the study area. However, seasonal exposure levels of 28.9, 37.6, 26.5, and 20.7 mu g/m(3) were estimated for the autumn, winter, spring, and summer seasons, respectively. This implies that local communities around the brick kiln in the Vhembe District are exposed to high levels of PM2.5, especially in winter. The PM2.5 levels in the brickmaking industries as well as its other sources in the Vhembe District, therefore, need to be lowered. Findings from population exposure level to pollutants can provide valuable data for formulating policies and recommendations on exposure reduction and public health protection. Implications: PM2.5 concentration in any given environment has high spatial and temporal variability due to the presence of diffused sources in the environment. Using ambient air concentrations to directly estimate population exposure without taking into consideration the disproportionate spatial and temporal distribution of the pollutant and the population may not yield accurate results on human exposure levels. It is, therefore, important to assess the aggregated PM2.5 exposure of a populace within a given area. This study therefore examines the PM2.5 population-weighted-exposure level of the host communities of the brickmaking industry in Vhembe District, South Africa.