Formation kinetics and mechanisms of ozone and secondary organic aerosols from photochemical oxidation of different aromatic hydrocarbons: dependence on NO<sub><i>x</i></sub> and organic substituents

Abstract. Aromatic hydrocarbons (AHs) contribute significantly to ozone and secondary organic aerosol (SOA) formation in the atmosphere, but their mechanisms are still unclear. Herein, photochemical oxidation of nine AHs was investigated a chamber. Only small amount produced from direct AHs, while lower number AH substituents resulted higher concentrated ozone. Addition NOx increased SOA production. The synergetic effect accelerated NO2 conversion NO reaction with boosted volatile intermediate formation. Promoting concentration VOC / ratio further rates concentrations both SOA. Additionally, enhanced increasing substituent negligibly affected by position. Differently, yield decreased an ortho-methyl-group-substituted AHs. Model fitting intermediates consistently confirmed that on phenyl ring inhibited generation dicarbonyl intermediates, which however were preferentially resulting different changing trends yield. restrained oligomerization another main cause for These results helpful understand transformation pollutants real atmosphere.