Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 115, Issue 20, Pages 5099-5104Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1801191115
Keywords
nitrogen oxides; emission regulations; decadal scale variation
Categories
Funding
- NASA Earth Observing System Program
- National Science Foundation
- NASA [NNX16AQ26G]
- Grants-in-Aid for Scientific Research [15K05296] Funding Source: KAKEN
- NASA [896097, NNX16AQ26G] Funding Source: Federal RePORTER
Ask authors/readers for more resources
Ground and satellite observations show that air pollution regulations in the United States (US) have resulted in substantial reductions in emissions and corresponding improvements in air quality over the last several decades. However, large uncertainties remain in evaluating how recent regulations affect different emission sectors and pollutant trends. Here we show a significant slowdown in decreasing US emissions of nitrogen oxides (NOx) and carbon monoxide (CO) for 2011-2015 using satellite and surface measurements. This observed slowdown in emission reductions is significantly different from the trend expected using US Environmental Protection Agency (EPA) bottom-up inventories and impedes compliance with local and federal agency air-quality goals. We find that the difference between observations and EPA's NOx emission estimates could be explained by: (i) growing relative contributions of industrial, area, and off-road sources, (ii) decreasing relative contributions of on-road gasoline, and (iii) slower than expected decreases in on-road diesel emissions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available