Smog exposure may increase emphysema risk and respiratory diseases severity: JAMA

Exposure to ozone air pollution — commonly referred to as "smog" — is associated with additional adverse respiratory outcomes in smokers, is the finding of a new study.The research team identified associations between long-term ozone exposures and increased respiratory disease severity, disease symptoms, and lung disease exacerbations in a cross-sectional analysis.

Researchers have found that long-term ambient ozone exposure was associated with worse respiratory outcomes and increased emphysema and gas trapping, independent of smoking and workplace exposures, in smokers with or at risk for chronic obstructive pulmonary disease.The new study has been published in JAMA Internal Medicine.

Nearly 1900 current or former heavy smokers, with or without chronic obstructive pulmonary disease, provided their home addresses over the prior 10 years, from which researchers estimated mean outdoor ozone concentrations. They also underwent numerous respiratory assessments.

After multivariable adjustment, participants' percentages of emphysema and air trapping on computed tomography increased linearly with increasing levels of estimated ozone concentration. Greater ozone concentration was also associated with worse respiratory-related quality-of-life, functional status, and dyspnea, as well as increased likelihood of respiratory exacerbations.

This study found that long-term historical ozone exposure was associated with reduced lung function, greater emphysema and air trapping on CT scan, worse patient-reported outcomes, and increased respiratory exacerbations for individuals with a history of heavy smoking. The association between ozone exposure and adverse respiratory outcomes suggests the need for continued reevaluation of ambient pollution standards that are designed to protect the most vulnerable members of the US population.

The researchers pointed out that adverse outcomes were observed at ozone levels far below limits imposed by U.S. regulators.

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JAMA Intern Med. Published online December 9, 2019. doi:https://doi.org/10.1001/jamainternmed.2019.5498