Seasonal variation of Nitrogen dioxide and particulate matter in the capital City (City of Tshwane) of South Africa and its compliance to South African Air Quality Standards

Abstract

Air pollution is a major issue in metropolitan areas, including the City of Tshwane in South Africa. With a growing urban population and increased vehicles on the road, the air quality in the city has become a concern. This study aims to assess air quality compliance in the City of Tshwane Metropolitan Municipality by analysing the levels of PM10 and NO2, two commonly monitored pollutants. The study obtained data from the SAAQIS database for the period from 2016 to 2020. The data was collected from network stations for ambient air monitoring within the city. The assessment of PM10 and NO2 concentrations was conducted according to the South African National Ambient Air Quality Standards (NAAQS). The objectives of the study were to investigate the variations in NO2 and PM10 levels across different seasons, evaluate the air quality within the city, and analyse the geographical patterns of these pollutants. The data analysis was performed using Microsoft Excel and SPSS techniques, while bar graphs and box and whisker plots were used to illustrate the results. The results of the study revealed that the City of Tshwane failed to comply with the NAAQS in terms of the recorded annual levels of NO2 and PM10 at the Booysens neighbourhood. The levels of these pollutants exceeded the recommended standards, indicating a risk of being declared a hotspot within the city. The findings suggest that human-induced activities, such as biomass burning and coal-powered power plants, significantly contribute to the emission of PM10 and NO2. The impact of these activities on pollutant levels is further exacerbated by prevailing weather conditions, particularly in residential zones during winter. In conclusion, this study highlights the urgent need to address air pollution in the City of Tshwane. The findings provide valuable insights into the sources and patterns of air pollution in the city, which can inform policy and decision-making to improve air quality and protect public health.