Air pollution ‘strongly linked’ to more nighttime coughing

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By Olivia Bowthorpe

Short-term increases in fine particulate air pollution are “strongly linked” to more frequent coughing during sleep, researchers have suggested.

A team from the University of Cambridge collected nocturnal audio recordings via a mobile app called Sleep Cycle.

Around 500 days of data were gathered from 32 cities in 12 countries between 2023 and 2025. The number of coughs detected per hour of sleep in each city was linked to daily concentrations of fine particulate matter (PM2.5).

The analysis by Cecilia Mascolo, professor of mobile systems at the university and colleagues, suggested a non-linear relationship, with increases in cough detectable even at relatively low PM2.5 concentrations.

There was a 2.4% increase in cough frequency for each 10 μg/m³ rise in daily PM2.5 pollution, even when weather conditions and circulating flu were taken into account.

Mascolo told Doctors.net.uk: "What doctors could take from this is that there may be no safe threshold for air pollution exposure, and that nighttime cough might be a sensitive early signal of that exposure worth asking patients about."