Satellite Data Reveals a Link Between NO2 Exposure and Asthma Exacerbations

Incorporating ground-level satellite-derived estimates of NO2 into multivariable models reveals a relationship between NO2 exposure and asthma exacerbations, according to a study published in AMIA Joint Summits on Translational Science. “By comparing three publicly available ambient NO2 measurement types, we found that satellite data captured more spatial variability than EPA regulatory monitor data for local health studies, and that inclusion of ground-level satellite estimates of NO2 into multivariable models of asthma exacerbations revealed a significant association between NO2 exposure and asthma exacerbations in Philadelphia,” wrote Alana Schreibman, Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania in Philadelphia, PA. “In contrast, use of spatially smoothed EPA regulatory monitor data might yield misleading results when used in studies of small regions.”

The study population included 16,744 people with asthma, 13,924 with no exacerbations during the study period, and 2820 with at least one exacerbation. De-identified electronic health record data from Penn Medicine patient encounters from January 1, 2015, to April 8, 2021, was obtained from Penn Data Store and used for the retrospective cohort analysis.

The comparison of ambient NO2 levels between the interpolated EPA NO2 raw satellite data and satellite-derived ground NO2 data revealed that the raw satellite data and satellite-derived ground NO2 levels were similar. However, the ground-level estimates were more varied. When interpolated EPA data were compared with satellite-derived data, the EPA measures did not capture regional differences well. In fact, the EPA monitors failed to detect certain NO2 hotspots.

The study also found an inverse relationship between estimated EPA NO2 exposure and asthma exacerbations. This discovery raises questions about the reliability of estimated EPA data for predicting health risks since the inverse relationship does not align with the known associations between NO2 and asthma risk. However, the associations between raw satellite NO2 and satellite-derived ground NO2 measures with asthma exacerbations were consistent with the known relationship between NO2 and exacerbation risk.

“Our findings demonstrate the potential of satellite-based pollution measurements to gain insights on local disease patterns, especially as these data become more widely available,” wrote the study authors.

Reference

Schreibman A, Xie S, Hubbard RA, Himes BE. Linking ambient NO2 pollution measures with electronic health record data to study asthma axacerbations. AMIA Jt Summits Transl Sci Proc. 2023;2023:467-476.