Results of a study that measured sleep efficiency have revealed that people who are more exposed to nitrogen dioxide and small air particles (known as PM 2.5s), are more likely to have low sleep efficiency.
Researchers say that the poor sleep could be down to the impact of air pollution on the body.
The study looked at the proportion of time participants spent asleep in bed at night compared with being awake (sleep efficiency).
It focussed on air pollution data captured for nitrogen dioxide and PM2.5 levels over a five-year period in six US cities, including data captured near the homes of the 1,863 participants.
Martha Billings, assistant professor of medicine at the University of Washington and co-author of the research, said: “Your nose, your sinuses and the back of your throat can all be irritated by those pollutants so that can cause some sleep disruption as well as from breathing issues.”
She added that pollutants entering the blood could have an effect on the brain and the regulation of breathing.
Researchers captured data from the participants’ medical-grade wearable devices over a period of seven consecutive days to monitor fine movements while they slept.
The team then took all of the participants and split them into four groups based on their air pollution exposure.
After taking into account factors including age, smoking status and medical conditions, the team found that those exposed to the highest levels of air pollution over five years were more likely to be in the bottom group for sleep efficiency than those exposed to the lowest levels.
However, it is not clear whether the pollution itself was affecting the participants’ sleep or whether the poorer sleep quality might be down to other pollution factors, such as traffic noise. Also, data from one week’s sleep might not reflect an individual’s typical sleep pattern.
Roy Harrison, professor of environmental health at the University of Birmingham, said: “Previous research has shown associations between nitrogen dioxide exposures and effects upon various physiological and biochemical functions in the body, as well as hospital admissions and mortality.
“It should therefore come as no surprise that such exposures also affect sleep patterns.”