The adverse effects of air pollution on the ocular surface have provided researchers with another way of measuring the impact of pollution on human health. A recent study found that air pollutants contribute to dry eye and should be mitigated as much as possible.

The researchers found that indoor and outdoor conditions greatly affect dry eye. Particulate matter and weather conditions, such as wind, humidity and temperature, have been shown to produce inflammatory responses. In air cabin studies, inflammatory mediators significantly increased in tear levels. The literature also points toward a negative correlation between tear breakup time and air pollution.

Some studies report that gaseous pollutants, such as NO₂, SO₂, O₃ and volatile organic compounds (formaldehyde, toluene, acetone, ethanol), present in cigarette smoke, fuel emissions, disinfectants and wood preservatives adversely affect the ocular surface. “Exposure to reactive gases can lead to cell death, oxidative stress and inflammation,” the study authors wrote in their paper. “Exposure to 0.4ppm ozone increased the secretion of inflammatory cytokines compared with controls in one study.”

The researchers suggested various methods of pollution mitigation, such as modifying humidity and temperature levels indoors and implementing air filtration. They noted that introducing more trees to remove larger amounts of air pollution and improve air quality would help urban environments. Minimizing pesticide use and reducing emissions from vehicles and industrial processes is another strategy. They concluded that personal mitigation strategies can be helpful, but large-scale environmental changes will be the most beneficial in the long-term.