Comparison of air pollutant standard index before and during the COVID-19 pandemic in DKI JakartaDedy Hartono, Syamsul Maarif, Deffi Ayu Puspitosari, Iko Saikanti Ponangsera and Jihan FitriyantiE3S Web Conf., 331 (2021) 02009DOI: https://doi.org/10.1051/e3sconf/202133102009