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Net changes in anomalies of criteria air pollutants during lockdown Phases 2–3 in comparison to 2016–2019 anomalies as baseline within the MCMA. The stars show significant changes during the COVID-19 lockdown calculated with the non-parametric Wilcoxon test, while the vertical bars show the 95% confidence intervals. *Level of significance p < 0.05. **Level of significance p < 0.01. ***Level of significance p < 0.001.
