Informal　environmental　regulation　(IER)　has　provided　grassroots　impetus　for　the　achievement　of　the　＂double　carbon＂　target,　and　its　bottom-up　＂voluntary　nature＂　provides　a　new　way　to　compensate　for　the　defects　of　formal　environmental　regulations　(ER).　Nevertheless,　empirical　research　in　this　territory　is　scarce　and　controversial,　so　this　research　strives　to　illuminate　the　depollution　effects　and　mechanism　of　IER.　Due　to　the　uneven　economic　development　of　the　various　regions　in　China,　probable　inflection　points　and　spillover　effect　of　IER　are　considered.　After　a　theoretical　derivation,　we　further　verify　the　hypothesis　through　a　panel　threshold　model　and　a　spatial　Durbin　model.　The　results　show　that:　The　results　show　that:　ER　and　IER　interact　positively　to　promote　emission　reduction.　As　GDP　per　capita　rises,　the　pollution　reduction　effect　of　netizens＇　environmental　opinion　becomes　progressively　stronger;　Effectiveness　of　residents＇　environmental　petitions　goes　from　strong　to　weak;　Awareness-raising　activities　hosted　by　environmental　non-government　organizations(ENGOs)　can　significantly　curb　pollution　regardless　of　economy.　Spatially,　the　participation　from　both　netizens　and　ENGOs　has　positive　spatial　spillover　depollution　effects.　However,　petitions　from　residents　only　have　local　effects.　Finally,　based　on　the　mechanisms　and　characteristics　of　different　participation　patterns,　we　make　tailored　policy　recommendations.