Just one hour of breathing polluted air can immediately impair lung and brain function, according to a new study. Notably, scent compounds in air fresheners — long perceived as "eco-friendly" — were found to inflict the greatest damage on the respiratory system.
Limonene in Air Fresheners Tops List for Lung Function Decline
According to a report by British daily The Daily Mail on the 27th (local time), citing experimental findings published by a research team led by Professor Gordon McFiggans of the Department of Atmospheric Sciences at the University of Manchester, healthy adults were exposed for one hour each to five different environments: clean air, citrus-scented limonene (used in air fresheners and detergents), diesel exhaust, wood smoke, and cooking fumes. The bodily responses varied by type of pollutant.
Among them, the substance that most significantly reduced lung function was limonene. Lung function in the limonene exposure group declined by 3.4%, while the wood smoke exposure group showed a 2.6% decrease. Diesel exhaust and cooking fumes followed.
The findings confirm that fragrance products, familiar to consumers for their eco-friendly and clean image, can in fact be toxic to the respiratory system.
The experiment measured lung function as well as memory, concentration, and emotional regulation in detail, after subjects were exposed to each environment and then given a four-hour rest period.
Diesel Exhaust Most Damaging to the Brain
In terms of brain function, diesel exhaust had the most adverse impact. The diesel exhaust exposure group showed a marked decline in "executive function," which encompasses planning, sustained concentration, and emotional regulation. The research team concluded that nitrogen oxides in the exhaust interfered with cerebral blood flow, causing the cognitive decline.
"Even though we matched the particulate matter concentrations of the pollutants used in the experiment, the bodily responses varied widely," Professor McFiggans said. "This shows that our bodies do not respond uniformly to all air pollution, and that where the pollutant originates and what it is composed of matter far more."
The research team warned that since such reactions appeared after just one hour of exposure, repeated exposure could lead to serious conditions such as permanent cognitive impairment or cancer. They called for further research on the long-term effects of various pollutants to support legislation and protect vulnerable groups, including children and the elderly.
