The coexistence of NO and CH 3 CHO in the air is considered to produce secondary peroxyacetyl nitrate (PAN) under sunlight irradiation, threatening the ecological environment and public health. Herein, we provide a simple strategy for the photocatalytic removal of NO and acetaldehyde (CH 3 CHO) on Sr 2 Sb 2 O 7 . In comparison with the single removal, the nearly complete removal of NO is reached by deep oxidation to NO 3 - with the assistance of CH 3 CHO. The underlying mechanism is revealed by GC-MS, in situ DRIFTS, and density functional theory calculations. The intermediates • CH 3 from CH 3 CHO and NO 2 - from NO tend to bond and further oxidize to CH 3 ONO 2 , thus promoting NO removal. CH 3 NO 2 and CH 3 ONO 2 are the key products instead of PAN on Sr 2 Sb 2 O 7 from the synergistic degradation of NO and CH 3 CHO. This work brings new insights into reaction pathway regulation for promoting performance and suppressing byproducts during synergistic air pollutant removal.