Characterisation of Ammonia Emissions from Gasoline and Gasoline Hybrid Passenger Cars

Real-world NH₃ emission factors and deterioration rates for gasoline and hybrid passenger cars from remote sensing measurements.

Analysis of 210,000 remote sensing measurements shows NH₃ emissions from gasoline passenger cars increase with vehicle mileage, with cold start emissions 1.7 times higher than hot exhaust, and introduces new speed-emission curves and a novel application of CO₂ failure rates to quantify real-world battery use in hybrid vehicles.

Abstract

Characterisation of Ammonia Emissions from Gasoline and Gasoline Hybrid Passenger Cars

Atmospheric Environment: X, Vol. 11, 100117, 2021

Recent evidence suggests NH₃ emissions from road vehicles play an important role in the formation of fine particulate matter, especially in urban areas. However, there is little data available for NH₃ emitted from road vehicles under real driving conditions, in part due to its lack of regulation in vehicle emission legislation. In this study, we use 210,000 vehicle emission remote sensing measurements to evaluate the complex mix of factors affecting NH₃ emissions from gasoline and gasoline hybrid passenger cars. The influence of vehicle model year and manufacturer on NH₃ emissions is considered, as well as the effect of vehicle deterioration. It is found that the amount of NH₃ emitted increases as vehicle mileage increases. A comparison of cold start and hot exhaust NH₃ emissions reveals that on average, cold start emissions are a factor of 1.7 times higher. New NH₃ emission factors are developed, in addition to speed-emission curves that are potentially useful for national inventories. A new application of remote sensing data is reported, whereby the proportion of failed CO₂ measurements for hybrid vehicles provides unique insight into the real world battery use of both conventional hybrid electric and plug-in hybrid electric vehicles, which is used to refine the NH₃ emission factors for these vehicles.

DOI