J Environ Sci (China). 2026 May;163:154-162. doi: 10.1016/j.jes.2025.07.002. Epub 2025 Jul 2.
ABSTRACT
Ammonia and nitrous oxide emissions impacts are beginning to get more attention, due to their potential to adversely effect on air pollution, climate and human health. Vehicle emission and laboratory simulation testing were employed to analyze the ammonia (NH3) and nitrous oxide (N2O) emission characteristics from a light-duty gasoline vehicle equipped with a monolithic three-way catalyst. It was found that NH3 emission factors were much higher than N2O emission factors, reaching 27.8 mg/km for an engine-aged catalyst. Catalyst aging and degradation resulted in the loss of three-way catalytic activity and reducibility, which led to a significant increase in the emissions of NH3 and N2O by-products. An engine aged catalyst showed higher N2O and NH3 emission than thermally aged catalyst for the real vehicle tests. Raman and electron probe results indicated that the agglomeration of active metals affects the dissociation process of NO on the metal surface, thereby affected the selectivity of the catalyst for N2O and NH3.
PMID:41887835 | DOI:10.1016/j.jes.2025.07.002
