The influence of COVID-19 restrictions on urban air pollution levels in Jambi, Indonesia: insights into ultrafine particles and carbon components

The COVID-19 pandemic led to unprecedented global lockdowns, providing a unique opportunity to study the effects of reduced human activities on air pollution especially PMs. This study investigated the impact of COVID-19 restrictions on urban air pollution levels in Jambi, Indonesia, with a particular focus on ultrafine particles (UFPs or PM_0.1) and carbonaceous components. PM concentrations, including UFP, PM₁, PM_2.5, PM₁₀, and TSP, were analyzed during the pandemic and compared with data before pandemic in 2018 and 2019. Our findings showed a significant reduction in PM levels during the pandemic. PM₁₀ levels exceeded WHO guidelines in only 10% of the measurements during the pandemic, compared to 62% before the pandemic. For PM_2.5, approximately 63% of the data met WHO standards during the pandemic, whereas all pre-pandemic measurements exceeded these guidelines. UFP concentrations in March and August 2021 decreased by over 50% and 58–68%, respectively, compared to pre-pandemic levels in August 2019. The study also revealed a substantial decrease in carbonaceous components, including organic carbon (OC) and elemental carbon (EC). Soot-EC levels, primarily emitted from vehicle emissions, decreased significantly, highlighting the positive impact of reduced vehicular traffic and biomass burning during the lockdown. These results underscored the potential benefits of targeted emission reduction strategies on urban air quality. The COVID-19 restrictions led to marked improvements in air quality in Jambi, providing valuable insights for future air quality management policies aimed at achieving sustainable urban environments and improved public health outcomes.