Long-term trends worldwide in ambient NO2 concentrations inferred from satellite observations
Date
2016
DOI
Authors
Geddes, J.A.
Martin, R.V.
Boys, B.L.
van Donkelaar, A.
Version
Published version
OA Version
Citation
J.A. Geddes, R.V. Martin, B.L. Boys, A. van Donkelaar. 2016. "Long-term trends worldwide in ambient NO2 concentrations inferred from satellite observations." Environmental Health Perspectives (Online), Volume 124, Issue 3, pp. 281 - 281.
Abstract
BACKGROUND: Air pollution is associated with morbidity and premature mortality. Satellite
remote sensing provides globally consistent decadal-scale observations of ambient nitrogen dioxide
(NO2) pollution.
OBJECTIVE: We determined global population-weighted annual mean NO2 concentrations from
1996 through 2012.
METHODS: We used observations of NO2 tropospheric column densities from three satellite instruments
in combination with chemical transport modeling to produce a global 17-year record of
ground-level NO2 at 0.1° × 0.1° resolution. We calculated linear trends in population-weighted
annual mean NO2 (PWMNO2) concentrations in different regions around the world.
RESULTS: We found that PWMNO2 in high-income North America (Canada and the United States)
decreased more steeply than in any other region, having declined at a rate of –4.7%/year [95%
confidence interval (CI): –5.3, –4.1]. PWMNO2 decreased in western Europe at a rate of –2.5%/year
(95% CI: –3.0, –2.1). The highest PWMNO2 occurred in high-income Asia Pacific (predominantly
Japan and South Korea) in 1996, with a subsequent decrease of –2.1%/year (95% CI: –2.7, –1.5).
In contrast, PWMNO2 almost tripled in East Asia (China, North Korea, and Taiwan) at a rate
of 6.7%/year (95% CI: 6.0, 7.3). The satellite-derived estimates of trends in ground-level NO2
were consistent with regional trends inferred from data obtained from ground-station monitoring
networks in North America (within 0.7%/year) and Europe (within 0.3%/year). Our rankings of
regional average NO2 and long-term trends differed from the satellite-derived estimates of fine
particulate matter reported elsewhere, demonstrating the utility of both indicators to describe
changing pollutant mixtures.
CONCLUSIONS: Long-term trends in satellite-derived ambient NO2 provide new information
about changing global exposure to ambient air pollution. Our estimates are publicly available at
http://fizz.phys.dal.ca/~atmos/martin/?page_id=232.
Description
License
Reproduced from Environmental Health Perspectives with permission from the authors.