Levels and drivers of urban black carbon and health risk assessment during pre- and COVID19 lockdown in Augsburg, Germany

This study aimed to evaluate the levels and phenomenology of equivalent black carbon (eBC) at the city center of Augsburg, Germany (01/2018 to 12/2020). Furthermore, the potential health risk of eBC based on equivalent numbers of passively smoked cigarettes (PSC) was also evaluated, with special emphasis on the impact caused by the COVID19 lockdown restriction measures. As it could be expected, peak concentrations of eBC were commonly recorded in morning (06:00-8:00 LT) and night (19:00-22:00 LT) in all seasons, coinciding with traffic rush hours and atmospheric stagnation. The variability of eBC was highly influenced by diurnal variations in traffic and meteorology (air temperature (T), mixing-layer height (MLH), wind speed (WS)) across days and seasons. Furthermore, a marked weekend effect was evidenced, with an average eBC decrease of similar to 35% due to lower traffic flow. During the COVID19 lockdown period, an average similar to 60% reduction of the traffic flow resulted in similar to 30% eBC decrease, as the health risks of eBC exposure was markedly reduced during this period. The implementation of a multilinear regression analysis allowed to explain for 53% of the variability in measured eBC, indicating that the several factors (e.g., traffic and meteorology) may contribute simultaneously to this proportion. Overall, this study will provide valuable input to the policy makers to mitigate eBC pollutant and its adverse effect on environment and human health.

Automated summary

This study evaluated the levels and phenomenology of equivalent black carbon (eBC) in Augsburg, Germany, and assessed its potential health risk based on equivalent numbers of passively smoked cigarettes (PSC), with a focus on the impact of COVID-19 lockdown measures. The study found that peak concentrations of eBC occurred during morning and night rush hours, influenced by traffic and meteorological factors. The eBC concentration decreased by an average of 35% on weekends due to lower traffic flow. During the COVID-19 lockdown, there was a significant reduction in eBC concentration due to reduced traffic flow.