We used two atmospheric models to test the implications of previously unexplored aldehyde photochemistry on the atmospheric levels of molecular hydrogen (H₂). We showed that the new photochemistry from aldehydes produces more H₂ over densely forested areas. Compared to the rest of the world, it is over these forested regions where the produced H₂ is more likely to be removed. The results highlight that other processes that contribute to atmospheric H₂ levels should be studied further.