Influencing factors on ammonia emissions from gasoline vehicles: A systematic review and meta-analysis
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View abstract on PubMed
Summary
This summary is machine-generated.Vehicular exhaust is a major source of ammonia emissions. This study used meta-analysis to find that vehicle speed, temperature, and mileage significantly impact ammonia emissions, necessitating new standards.
Area Of Science
- Environmental Science
- Atmospheric Chemistry
- Automotive Engineering
Background
- Ammonia (NH3) is a key precursor to secondary inorganic aerosols and new particle formation.
- Vehicular exhaust is a primary source of atmospheric ammonia in urban environments.
- Existing research on gasoline vehicle ammonia emissions shows inconsistencies, lacking a unified explanatory framework.
Purpose Of The Study
- To reconcile inconsistencies in gasoline vehicle ammonia emission data using meta-analysis.
- To precisely identify factors influencing ammonia emissions from gasoline vehicles.
- To provide a comprehensive understanding of ammonia emission dynamics in urban air quality.
Main Methods
- Conducted a meta-analysis of 537 ammonia emission factors extracted from over 1628 publications.
- Analyzed the influence of emission standards, engine type, ambient temperature, mileage, vehicle speed, and engine displacement.
- Investigated the role of catalyst properties, lambda, and residence time (space velocity).
Main Results
- The combined ammonia emission factor from gasoline vehicles is 23.57 ± 24.94 mg/km.
- Vehicle speed, temperature, mileage, engine type, and displacement significantly impact ammonia emission factors, collectively explaining up to 50.63% of variations.
- Vehicle speed was identified as the most significant factor influencing ammonia emissions.
- Ammonia emission control is insufficient under low/ultra-high speeds, low temperatures, and high mileage conditions.
Conclusions
- Ammonia emission factors do not consistently decrease with stricter emission standards.
- There is a need to incorporate ammonia emission indicators and targeted testing procedures into motor vehicle emission standards.
- Current emission control strategies are inadequate for specific driving conditions, highlighting the need for revised regulations.
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