Scielo RSS <![CDATA[Clean Air Journal]]> http://www.scielo.org.za/rss.php?pid=2410-972X20200002&lang=en vol. 30 num. 2 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Air pollution in Kigali, Rwanda</b><b>: </b><b>spatial and temporal variability, source contributions, and the impact of car-free Sundays</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200001&lng=en&nrm=iso&tlng=en Ambient air pollution, particularly fine particulate mass (PM25) and ozone (O3), is associated with premature human mortality and other health effects, but monitoring is scarce to non-existent in large parts of Africa. Lower-cost real-time affordable multi-pollutant (RAMP) monitors and a black carbon (BC) monitor were deployed in Kigali, Rwanda to fill the air quality data gap here. PM25 data were corrected using data from a coincident, short-term campaign that used standard filter-based gravimetry, while gas data were verified by collocation with reference carbon monoxide (CO) and O3 monitors at the Rwanda Climate Observatory at Mt Mugogo, Rwanda. Over March 2017-July 2018, the ambient average PM25 in Kigali was 52 μg/m³, significantly higher than World Health Organization (WHO) Interim Target 1. Study average BC was 4 μg/m³, comparable to mid-sized urban areas in India and China and significantly higher than BC in cities in developed countries. Spatial variability across various urban background sites in Kigali appears to be limited, while PM25 at Mt Mugogo is moderately correlated with PM25 in Kigali. A sharp diurnal profile is observed in both PM25 and BC, with the Absorption Angstrom Exponent (AAE) indicating that the morning peak is associated with rush-hour traffic-related air pollution (TRAP) while the late evening peak can be attributed to both traffic and domestic biofuel use. PM25 in the dry seasons is about two times PM25 during the following wet seasons while BC is 40-60% higher. Local sources contribute at least half the ambient PM25 during wet seasons and one-fourth during dry seasons. Traffic restrictions on some Sundays appear to reduce PM25 and BC by 10-12 μg/m³ and 1 μg/m³ respectively, but this needs further investigation. Dry season ozone in Kigali can exceed WHO guidelines. These lower-cost monitors can play an important role in the continued monitoring essential to track the effectiveness of pollution-control policies recently implemented in Rwanda. <![CDATA[<b>The impacts of commissioning coal-fired power stations on air quality in South Africa: insights from ambient monitoring stations</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200002&lng=en&nrm=iso&tlng=en The South African electricity sector is known for its heavy reliance on coal. The aim of this study is to assess the impacts of increasing SO2 and PM emissions from the three return-to-service power stations (Komati, Camden and Grootvlei), and the newly constructed Medupi power station on ambient air quality measured in the vicinities of these power stations. Trends in ambient pollution concentrations were determined using Theil-Sen analysis. The correlation between the emissions and ambient pollution concentrations at nearby monitoring stations was determined with the Spearman partial rank correlation coefficient. Lastly, compliance of ambient pollution concentrations with the South Africa National Ambient Air Quality Standards was assessed. Few statistically significant trends in ambient SO2 and PM10 concentrations are found, and there is little correlation between increasing power station emissions and ambient pollutant concentrations in the vicinity. It is only at Camden monitoring station where there are increases in PM10 concentrations from the direction of Camden power station, and at Grootvlei monitoring station where increasing SO2 concentrations are from the directions of Grootvlei and Lethabo power stations. A strong, positive correlation between power station emissions and ambient concentrations exists only for SO2 at Grootvlei monitoring station and PM10 at Medupi monitoring station (although it is likely that the correlation at Medupi is related to construction and vehicle activity, and not emissions from Medupi power station stacks). It is concluded that the establishment of monitoring stations in the vicinities of power stations is necessary but not sufficient to monitor their impact on air quality in the surrounds. <![CDATA[<b>Chemical characterization of fine particulate matter, source apportionment and long-range transport clusters in Thohoyandou, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200003&lng=en&nrm=iso&tlng=en This paper presents a chemical characterization of fine particulate matter (PM25) in air masses passing through Thohoyandou and further determines their sources. PM25 samples were collected and quantified using the gravimetric method. X-ray fluorescence, smoke stain reflectometer, optical transmissometer and scanning electron microscopy - energy dispersive X-Ray spectroscopy were used to determine the chemical and morphological composition of the particulate matter. The source apportionment was done using principal component analysis while the HYSPLIT model was used to depict the long-range transport clusters. The mean of concentrations of PM25, soot, black carbon and UVPM were 10.9 ug/m³, 0.69x10-5 m-1, 1.22 μg/m³ and 1.40 μg/m³, respectively. A total of 24 elements were detected in the PM25 with Pd, Sn, Sb, Mg, Al, and Si being the dominant elements. SEM-EDS have shown the presence of irregular, flat and spherical particles which is associated with crustal material and industrial emissions. Source apportionment analysis revealed six major sources of PM25 in Thohoyandou namely, crustal materials, industrial emissions, vehicular emissions, urban emissions, fossil fuel combustion and fugitive-Pd. Air parcels that pass through Thohoyandou were clustered into four groupings. The major pathways were from the SW Indian Ocean, Atlantic Ocean, and inland trajectories. Clusters from the ocean are associated with low concentration, while inland clusters are associated with high concentration of PM25. The PM25 levels occasionally exceeded the daily WHO guideline (25 μg/m³) in Thohoyandou and the sources of PM25 extend beyond the borders. This study recommends that further studies need to be carried out to assess the health impacts of PM25 in Thohoyandou. <![CDATA[<b>An exploratory characterisation of the carbon and stable isotope composition of atmospheric particulate matter from opencast coal mining activities and adjacent communities</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200004&lng=en&nrm=iso&tlng=en Standard source apportionment techniques for atmospheric particulate (PM) collected near opencast coal mines using inorganic markers only are limited by the similarity in the mineral components in the overburden and at adjacent residential locations. This study explores the use of the stable carbon (C) and nitrogen (N) isotope ratios (13C/12C and 15N/14N) and thermal optical methods to differentiate sources of carbonaceous material in the atmospheric PM samples from the opencast coal mines and adjacent communities. Results show isotopic and OC/EC ratio differences between atmospheric PM samples from the opencast coal mines and communities, although distinguishing between the contributions of coal combustion, liquid fuel combustion and the domestic use of biomass requires further analysis. <![CDATA[<b>Air Pollution and its impacts on health in Africa -insights from the State of Global Air 2020</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200005&lng=en&nrm=iso&tlng=en Standard source apportionment techniques for atmospheric particulate (PM) collected near opencast coal mines using inorganic markers only are limited by the similarity in the mineral components in the overburden and at adjacent residential locations. This study explores the use of the stable carbon (C) and nitrogen (N) isotope ratios (13C/12C and 15N/14N) and thermal optical methods to differentiate sources of carbonaceous material in the atmospheric PM samples from the opencast coal mines and adjacent communities. Results show isotopic and OC/EC ratio differences between atmospheric PM samples from the opencast coal mines and communities, although distinguishing between the contributions of coal combustion, liquid fuel combustion and the domestic use of biomass requires further analysis. <![CDATA[<b>Low-cost sensors, an interesting alternative for air quality monitoring in Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200006&lng=en&nrm=iso&tlng=en Standard source apportionment techniques for atmospheric particulate (PM) collected near opencast coal mines using inorganic markers only are limited by the similarity in the mineral components in the overburden and at adjacent residential locations. This study explores the use of the stable carbon (C) and nitrogen (N) isotope ratios (13C/12C and 15N/14N) and thermal optical methods to differentiate sources of carbonaceous material in the atmospheric PM samples from the opencast coal mines and adjacent communities. Results show isotopic and OC/EC ratio differences between atmospheric PM samples from the opencast coal mines and communities, although distinguishing between the contributions of coal combustion, liquid fuel combustion and the domestic use of biomass requires further analysis. <![CDATA[<b>A summary of the paper "Natural archives of long-range transported contamination at the remote lake Letseng-la Letsie, Maloti Mountains, Lesotho"</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200007&lng=en&nrm=iso&tlng=en Standard source apportionment techniques for atmospheric particulate (PM) collected near opencast coal mines using inorganic markers only are limited by the similarity in the mineral components in the overburden and at adjacent residential locations. This study explores the use of the stable carbon (C) and nitrogen (N) isotope ratios (13C/12C and 15N/14N) and thermal optical methods to differentiate sources of carbonaceous material in the atmospheric PM samples from the opencast coal mines and adjacent communities. Results show isotopic and OC/EC ratio differences between atmospheric PM samples from the opencast coal mines and communities, although distinguishing between the contributions of coal combustion, liquid fuel combustion and the domestic use of biomass requires further analysis. <![CDATA[<b>The need for open data on air quality monitoring in logistically difficult environments</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2410-972X2020000200008&lng=en&nrm=iso&tlng=en Standard source apportionment techniques for atmospheric particulate (PM) collected near opencast coal mines using inorganic markers only are limited by the similarity in the mineral components in the overburden and at adjacent residential locations. This study explores the use of the stable carbon (C) and nitrogen (N) isotope ratios (13C/12C and 15N/14N) and thermal optical methods to differentiate sources of carbonaceous material in the atmospheric PM samples from the opencast coal mines and adjacent communities. Results show isotopic and OC/EC ratio differences between atmospheric PM samples from the opencast coal mines and communities, although distinguishing between the contributions of coal combustion, liquid fuel combustion and the domestic use of biomass requires further analysis.