Diurnal and Seasonal Variations of Particulate Matter (PM2.5) at a Tailing Storage Facility and Nearby Community

Abstract

Most of the world’s largest gold mines are found in South Africa, contributing mainly to the world’s gold production. Gold mining activities led to the formation of Gold Mine Tailings Storage Facilities (TSF), a potential source of PM2.5 dust emissions impacting air quality and human health. This study selected a TSF in Evander and the eMbalenhle community as the source and receptor, respectively. Many studies have reported ambient daily and seasonal variations of PM2.5. However, the temporal variations of PM2.5 at the source and the receptor are underreported in the literature. The study aimed to analyse the diurnal and seasonal variations of PM2.5 at the TSF and in the community. Ambient PM2.5 concentrations at the two sites were measured for one year (February 2022 to February 2023) using Clarity Node-S low-cost monitors. Meteorological data for the same period were obtained from the South African Air Quality Information System (SAAQIS). The data were analysed using packages in R-Studio. Higher values for PM2.5 concentrations were observed in winter, with lower values recorded in summer and spring. The daily concentration averages at the community site and TSF were 44.5 and 32.2 µg/m3, respectively. The 24-hour averages at the TSF and community site exceeded the PM2.5 National Ambient Air Quality Standard (NAAQS) of 40 µg/m3 and the WHO (World Health Organisation) Guideline of 15 µg/m3. Pronounced diurnal variations were observed in the community, displaying a bimodal pattern with peaks in the morning (5 a.m.) and evening (4 p.m.). Higher PM2.5 concentrations were recorded in the community compared to the TSF, indicating other sources of pollution in the receiving environment.