Source apportionment of fine atmospheric particles using positive matrix factorization in Pretoria, South Africa

Abstract

Outdoor and indoor air pollution have been regarded as a serious issue in South Africa, with the emissions of various air pollutants and their resulting concentrations in the atmosphere being a major source of concern. For example, nearly 80% of the global population was subjected to air pollution levels that surpassed the World Health Organization (WHO) air quality guidelines in 2011. Pollution from a variety of sources has had a significant effect on air quality, posing a direct threat to the critical roles the environment plays in preserving and sustaining life by absorbing harmful ultraviolet radiation, warming the surface, and controlling the earth’s temperature. Particulate matter (PM) suspended in the air for hours or days can travel a long distance, making it a long-range transported pollutant that is influenced by particle size, chemical composition, and other physical and biological characteristics. PM2.5 (particles smaller than 2.5 μm) has received a lot of attention recently because of the negative impact it has on human health, i.e., its potential to penetrate human lungs. Furthermore, epidemiological studies have revealed a connection between PM and a variety of health problems. Source apportionment is an important air quality management tool for providing information about source contributions required for pollution abatement strategies. However, not many studies have applied air mass backward trajectory modelling with source apportionment model analysis to investigate the sources of PM.