Air Pollution Estimation and Trends in Mainz (2017–2022): A Case Study

Air pollution is a pressing global environmental challenge, with PM2.5 (particulate matter with a diameter of less than 2.5 micrometers) being recognized as one of the most hazardous pollutants to human health. Prolonged exposure to PM2.5 has been linked to respiratory diseases, cardiovascular conditions, and premature mortality. It has been shown that 99% of the world population is exposed daily to pollutant concentrations exceeding the World Health Organization’s recommended safe levels. This study compares PM2.5 levels measured by satellite data from the Atmospheric Composition Analysis Group at Washington University in St. Louis with ground-based measurements from the Sensor Community initiative using SDS011 sensors deployed in Mainz, Germany. In addition, we investigated whether Mainz has achieved a positive trend in reducing PM2.5 concentrations and assessed how well the city complies with WHO standards. Our results indicate that: (a) satellite measurements consistently record higher PM2.5 values than ground-based sensors, (b) Mainz has experienced a decreasing trend in PM2.5 levels in recent years, although some of this reduction may be attributed to pandemic-related lockdowns, and (c) pollution levels in Mainz remain significantly above WHO guideline limits.