Nitrous oxide (N₂O) is a greenhouse gas (GHG) and an ozone-depleting substance. Municipal solid waste (MSW) management and treatment activities are some of the sources of GHG emissions. However, the biogenic GHG emissions during the predisposal stage of MSW management, during which waste is transferred to garbage cans and then transported to disposal sites, have received little attention. In this study, household waste was divided into food and non-food waste, and the effects of these types of waste and different oxygen concentrations (21%, 10%, and 1%) on N₂O emissions were investigated. A¹⁵N-labeled isotope experiment was conducted over three days to determine the contributions of nitrification and denitrification to N₂O emissions. The results showed that the N₂O fluxes first increased and then decreased during the three-day tests at different O₂ concentrations. The maximum N₂O flux of 1469.59 ± 1004.32 μg N·kg^-1 wet waste·h^-1 occurred during the predisposal of food waste at an O₂ concentration of 21%, with the total N₂O emissions reaching 20.26 ± 10.87 mg N·kg^-1 wet waste, which exceeds the emissions from some waste disposal processes, such as composting and landfills. The N₂O emissions decreased in the following order: food waste > household waste > non-food waste. For food waste, the peak value and total amount of N₂O emissions decreased significantly as the O₂  concentration decreased. In contrast, the N₂O emissions from non-food waste increased as the O₂ concentration decreased. Denitrification was the predominant biogenic source of N₂O emissions; it accounted for over 60% of N₂O production in all treatments. Nitrification also played an important role in N₂ O emissions during the early predisposal stage.