AUTHOR=Ni Bing-Jie TITLE=Grand challenges in environmental engineering JOURNAL=Frontiers in Environmental Engineering VOLUME=1 YEAR=2022 URL=https://www.frontiersin.org/journals/environmental-engineering/articles/10.3389/fenve.2022.1052154 DOI=10.3389/fenve.2022.1052154 ISSN=2813-5067