Source apportionment of ambient fine and coarse aerosols in Embalenhle and Kinross, South Africa

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 atmospheric aerosol loading and the contributing air pollution sources will assist with the formulation and implementation of these strategies. This study aims to assess the composition and sources of the aerosol loading in Embalenhle and Kinross located on the Highveld. Fine (PM2.5) and coarse (PM2.5-10) aerosol samples were collected during summer and winter, which were quantified using the gravimetric method. Wavelength-Dispersive X-Ray Fluorescence (WD-XRF) and Ion Chromatography (IC) analysis were used to determine the chemical composition of aerosols. Mean PM2.5 concentrations in Embalenhle and Kinross ranged from 16.3 to 34.1 µg/m3 during winter and 7.4 to 19.0 µg/m3 during summer. Mean PM10-2.5 concentrations ranged from 10.3 to 114 µg/m3 during winter and 5.9 to 11.2 µg/m3 during summer. Si, Al, S, Na (winter only), Ca (summer only), SO42- and NH4+ were the most abundant species in PM2.5 during both seasons. In PM10-2.5, Si, Al, Na (winter only), SO42- and F- were the most abundant species during both seasons. The elements S and Ca also had high abundances at Embalenhle and Kinross, respectively, during summer. Source apportionment was undertaken using Positive Matrix Factorisation, which identified five sources. Dust, secondary aerosols, domestic combustion, wood and biomass burning, and industry were determined to be the contributing sources. Any measures to mitigate particulate air pollution on the Highveld should consider these key sources.

Introduction to the special issue: Air quality on the South African Highveld

This call for papers sought to consolidate the most recent air quality research undertaken in the Highveld to build on the foundation established by Tyson, Kruger and Louw (1987). Our hope is that through consolidating the investigations, assessments, and ambient air quality monitoring, that management interventions can be refined, improved, and more effectively implemented. Such interventions having the effect of materially reducing the prevailing disease burden and ultimately giving effect to the constitutional right of people living on the Highveld, to an environment that is not harmful to their health or welfare.

Estimating lightning NOx production over South Africa

Research Brief

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.

Does apparent temperature modify the effects of air pollution on respiratory disease hospital admissions in an industrial area of South Africa?

Background: Temperature and air pollution are often treated as separate risk factors and very few studies have investigated effect modification by temperature on air pollution, and the impact of this interaction on human health in Africa. This study therefore investigated the modifying effects of temperature on the association between air pollution and Respiratory disease (RD) hospital admission in South Africa. Methods: RD admission data (ICD10 J00-J99) were obtained from two hospitals located in Secunda, South Africa beween 1 January 2011 to 31 October 2016. NO2, SO2, PM10, PM2.5, temperature and relative humidity data were obtained from the South African Weather Services. A case-crossover epidemiological study design was applied and lag0-1 was used. Models were adjusted for public holidays and Apparent Temperature (Tapp). Tapp was classified as warm (Tapp>75th percentile), cold (Tapp<25th percentile) and normal (Tapp 25th-75th percentile). Results: Of the 14 568 RD admissions, approximately equal number of females and males were admitted. The average daily NO2, SO2, PM2.5 and PM10 levels were 12.4 μm/m3, 8.5 μm/m3, 32.3 μm/m3 and 68.6 μm/m3, respectively. Overall, a 10 μm/m3 increase in SO2 on warm days was associated with an increase in RD hospital admissions among the patients by 8.5% (95% Conf. Int: 0.4%, 17.2%) and 8.4% (95% Conf. Int: 0.3%, 17.1%) after adjustment for PM2.5 and PM10 respectively. However, increasing PM2.5 or PM10 by 10 μm/m3 was associated with an increase in RD hospital admissions when the temperature was normal after adjusting for SO2. On cold days there were significant associations between the SO2 and RD admissions among the 0-14 year age group after adjusting for either PM2.5 (6.5%; 95% Conf.Int: 0.9%, 12.4%) or PM10 (5.5%; 95% Conf.Int: 0.3%, 11.1%). Conclusions: SO2 was affected by extremes of temperature while the particulate matters had effect on RD admission during normal temperature in Secunda.

Modeling tropospheric ozone and particulate matter in Tunis, Tunisia using generalized additive model

The main purpose of this paper is to analyze the sensitivity of tropospheric ozone and particulate matter concentrations to changes in local scale meteorology with the aid of meteorological variables (wind speed, wind direction, relative humidity, solar radiation and temperature) and intensity of traffic using hourly concentration of NOX, which are measured in three different locations in Tunis, (i.e. Gazela, Mannouba and Bab Aliwa). In order to quantify the impact of meteorological conditions and precursor concentrations on air pollution, a general model was developed where the logarithm of the hourly concentrations of O3 and PM10 were modeled as a sum of non-linear functions using the framework of Generalized Additive Models (GAMs). Partial effects of each predictor are presented. We obtain a good fit with R² = 85% for the response variable O3 at Bab Aliwa station. Results show the aggregate impact of meteorological variables in the models explained 29% of the variance in PM10 and 41% in O3. This indicates that local meteorological condition is an active driver of air quality in Tunis. The time variables (hour of the day, day of the week and month) also have an effect. This is especially true for the time variable “month” that contributes significantly to the description of the study area.