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Analysis of long‐term observations of NO x and CO in megacities and application to constraining emissions inventories
Author(s) -
Hassler Birgit,
McDonald Brian C.,
Frost Gregory J.,
Borbon Agnes,
Carslaw David C.,
Civerolo Kevin,
Granier Claire,
Monks Paul S.,
Monks Sarah,
Parrish David D.,
Pollack Ilana B.,
Rosenlof Karen H.,
Ryerson Thomas B.,
Schneidemesser Erika,
Trainer Michael
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl069894
Subject(s) - megacity , emission inventory , environmental science , term (time) , tropospheric ozone , atmospheric sciences , diesel fuel , meteorology , ozone , air pollutants , climatology , air pollution , geography , air quality index , economy , economics , chemistry , geology , physics , organic chemistry , quantum mechanics
Long‐term atmospheric NO x /CO enhancement ratios in megacities provide evaluations of emission inventories. A fuel‐based emission inventory approach that diverges from conventional bottom‐up inventory methods explains 1970–2015 trends in NO x /CO enhancement ratios in Los Angeles. Combining this comparison with similar measurements in other U.S. cities demonstrates that motor vehicle emissions controls were largely responsible for U.S. urban NO x /CO trends in the past half century. Differing NO x /CO enhancement ratio trends in U.S. and European cities over the past 25 years highlights alternative strategies for mitigating transportation emissions, reflecting Europe's increased use of light‐duty diesel vehicles and correspondingly slower decreases in NO x emissions compared to the U.S. A global inventory widely used by global chemistry models fails to capture these long‐term trends and regional differences in U.S. and Europe megacity NO x /CO enhancement ratios, possibly contributing to these models' inability to accurately reproduce observed long‐term changes in tropospheric ozone.