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We examine whether salient deterioration in local air quality mobilizes bottom-up engagement with a green digital program. Using user-month panel data on 200,000 users of Ant Forest\u2014the world's largest green mobile program\u2014across 331 Chinese cities from 2019 to 2020, we show that the same individuals respond to severe local pollution by generating more green energy through eligible low-carbon activities, engaging more intensively and more frequently with the program to collect the resulting credits, and redeeming more credits for collaborative tree planting in the following month. The responses are dose-responsive\u2014larger under \u201cHazardous\u201d (AQI \u2265 300) than \u201cVery Unhealthy\u201d (AQI \u2265 200) conditions\u2014and representative survey data show that pollution exposure raises stated environmental concern. Our findings indicate that digital green programs can help translate heightened environmental concern into measurable green engagement and downstream environmental contributions, complementing top-down regulation.<\/jats:p>","DOI":"10.1093\/pnasnexus\/pgag326","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T07:56:12Z","timestamp":1790322972000},"source":"Crossref","is-referenced-by-count":1,"title":["Salient air pollution mobilizes bottom-up green engagement: Evidence from the world's largest green mobile program"],"prefix":"10.1093","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3025-3119","authenticated-orcid":false,"given":"Jiafu","family":"An","sequence":"first","affiliation":[{"name":"Department of Real Estate and Construction, University of Hong Kong , Hong Kong SAR 999077 ,","place":["China"]},{"name":"Institute for Climate and Carbon Neutrality, The University of Hong Kong , Hong Kong SAR 999077 ,","place":["China"]},{"name":"Urban Systems Institute, The University of Hong Kong , Hong Kong SAR 999077 ,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiawen","family":"Huang","sequence":"additional","affiliation":[{"name":"Wang Yanan Institute for Studies in Economics (WISE), School of Economics, Xiamen University , Xiamen 361005, Fujian ,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4205-8633","authenticated-orcid":false,"given":"Chen","family":"Lin","sequence":"additional","affiliation":[{"name":"Faculty of Business and Economics, University of Hong Kong , Hong Kong SAR 999077 ,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1159-3134","authenticated-orcid":false,"given":"Difang","family":"Huang","sequence":"additional","affiliation":[{"name":"Academy of Mathematics and Systems Science, Chinese Academy of Sciences , Beijing 100190 ,","place":["China"]},{"name":"School of Economics and Management, University of Chinese Academy of Sciences , Beijing 100049 ,","place":["China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"2026101523463748300_pgag326-B1","doi-asserted-by":"crossref","DOI":"10.1596\/978-1-4648-1816-5","volume-title":"The global health cost of PM2.5 air pollution: a case for action beyond 2021","author":"World Bank","year":"2022"},{"key":"2026101523463748300_pgag326-B2","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1038\/s41586-018-0263-3","article-title":"Robust relationship between air quality and infant mortality in Africa","volume":"559","author":"Heft-Neal","year":"2018","journal-title":"Nature"},{"key":"2026101523463748300_pgag326-B3","doi-asserted-by":"crossref","first-page":"1223","DOI":"10.1016\/S0140-6736(20)30752-2","article-title":"Global burden of 87 risk factors in 204 countries and territories, 1990\u20132019: a systematic analysis for the Global Burden of Disease Study 2019","volume":"396","author":"GBD 2019 Risk Factors Collaborators","year":"2020","journal-title":"Lancet"},{"key":"2026101523463748300_pgag326-B4","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1038\/s41562-018-0521-2","article-title":"Air pollution lowers Chinese urbanites\u2019 expressed happiness on social media","volume":"3","author":"Zheng","year":"2019","journal-title":"Nat Hum Behav"},{"key":"2026101523463748300_pgag326-B5","doi-asserted-by":"crossref","first-page":"470","DOI":"10.1038\/s41893-022-01032-1","article-title":"Urbanites\u2019 mental health undermined by air pollution","volume":"6","author":"Cao","year":"2023","journal-title":"Nat Sustain"},{"key":"2026101523463748300_pgag326-B6","volume-title":"State of global air 2024. 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