biostudies-literatureJin QNational Natural Science Foundation of China119479https://www.ebi.ac.uk/biostudies/studies/S-EPMC9664768biostudies-literatureUnknown294As the new coronavirus pandemic enters its third year, its long-term impact on the urban environment cannot be ignored, especially in megacities with more than millions of people. Here, we analyzed the changes in the concentration levels, emission sources, temporal variations and holiday effects of ambient fine particulate matter (PM_2.5) and its chemical components in the pre- and post-epidemic eras based on high-resolution, long time-series datasets of PM_2.5 and its chemical components in Chengdu. In the post-epidemic era, the PM_2.5 concentration in Chengdu decreased by 7.4%, with the components of PM_2.5 decreasing to varying degrees. The positive matrix factorization (PMF) results indicated that the emissions from soil dust and industrial produAtmospheric environment (Oxford, England : 1994)Short- and long-term impacts of the COVID-19 epidemic on urban PM_2.5 variations: Evidence from a megacity, Chengdu.PMC966476841771248Huang CFeng MJin QLuo YMeng XfalseShort- and long-term impacts of the COVID-19 epidemic on urban PM_2.5 variations: Evidence from a megacity, Chengdu.As the new coronavirus pandemic enters its third year, its long-term impact on the urban environment cannot be ignored, especially in megacities with more than millions of people. Here, we analyzed the changes in the concentration levels, emission sources, temporal variations and holiday effects of ambient fine particulate matter (PM_2.5) and its chemical components in the pre- and post-epidemic eras based on high-resolution, long time-series datasets of PM_2.5 and its chemical components in Chengdu. In the post-epidemic era, the PM_2.5 concentration in Chengdu decreased by 7.4%, with the components of PM_2.5 decreasing to varying degrees. The positive matrix factorization (PMF) results indicated that the emissions from soil dust and industrial produ2023-01-01T00:00:00Z2023 Feb2026-04-12T15:07:38.43Z2025-02-19T00:47:18.358ZS-EPMC96647683640787410.1016/j.atmosenv.2022.119479