A decadal analysis of particulate matter (PM2.5) and surface ozone (O3) over Vaal Priority Area, South Africa

Abstract

Atmospheric pollutants that affect human health most significantly are particulate matter (PM_2.5) and surface ozone (O₃). This paper analysed the long-term temporal trends for PM_2.5 and ground level O₃ for six air quality monitoring stations in the Vaal Triangle Area of South Africa from 2007 to 2017. Research has been conducted on the short-term temporal trends for PM_2.5 concentration and surface O₃ concentrations. There are no studies that have focussed on the long-term temporal trends for PM_2.5 and O₃ in the Vaal Triangle Area of South Africa, because these air quality monitoring stations have only existed for a period of approximately 11 years. The data used in this study is derived from ground-based instruments from the South African Weather Service. Temporal patterns for time of day, days of the week, and seasons were observed for all air quality stations. PM_2.5 concentration increased during early mornings and late afternoons, with higher concentration during weekdays than weekends and an increase from late winter through to spring and summer. Surface O₃ concentrations peaked during the spring and summer months and during midday when there was maximum sunlight acting as a catalyst for photochemical reactions. The long term trends illustrated that there has been no significant decrease in annual average concentration for PM_2.5 in four of the six stations and surface O₃ for the six stations in the past 10 years in the Vaal Triangle Area of South Africa.