Aircraft also a contributor to air pollution
Air pollution is a global health threat, with it being the fifth leading risk factor for death. Based on data from the Global Burden of Disease Study, exposure to outdoor fine particulate matter – air pollutants 2.5 microns or less in diameter (PM2.5) – accounted for 4.2 million deaths worldwide and 103.1 million disability-adjusted life-years in 2015.
Even worse, the World Health Organization (WHO) reports that over 80 percent of city dwellers are exposed to air pollution levels that exceed the WHO guideline level of 10 micrograms per cubic meters. Low- and middle-income countries, in particular, suffer from the highest exposures.
Earlier studies point to a link between particulate matter and negative health outcomes. Exposure to car emissions, for instance, was found to increase the risk of chronic diseases and worsen the symptoms of asthma. But ground vehicles are not the only sources of harmful particulate matter.
According to study published in Environmental Research Letters, aviation-related pollution is also a significant contributor to global air quality degradation. In fact, emissions from take-off, cruise, and landing could easily account for the over-16,000 deaths a year caused by poor air quality – something that's often overlooked by policy-makers when addressing air pollution.
One reason for this could be the paucity of information regarding the deleterious effects of aircraft emissions on human health. While a few studies have focused on this, they made use of self-reported respiratory symptoms rather than data from clinical research. Hence, their findings do not paint a complete picture of the adverse effects of aviation emissions. (Related: Is this why so many city dwellers have health issues? Air pollution found to radically increase stress hormones and alter metabolism.)
For their study, the Swiss researchers investigated the effects of exposure to a turbofan engine using human lung cells. Most aircraft use a turbofan engine since it can produce incredible amounts of thrust while maintaining fuel-efficiency. The researchers exposed the cells to thrust conditions that simulated aircraft take-off and ground idling using a CFM56-7B turbofan, an engine used in many of today's aircraft. After an hour-long exposure, they looked at cellular responses to determine the impact of particle emissions.
The researchers found that even short-term exposure to turbofan emissions can impair cellular function. In particular, they noted an increase in oxidative stress and cytotoxicity (cell toxicity). Oxidative stress refers to an imbalance between the amounts of free radicals and antioxidants. Oxidative stress is a precursor to chronic diseases like diabetes, cardiovascular disease, and cancer.
The researchers also found that exposure to particulate matter from a turbofan running on commercial fuel and simulating ground idling caused the highest cytotoxicity and oxidative stress response. In addition, they noted that exposure to it can render the airways vulnerable to other pollutants and pathogens.
“This study establishes, for the first time, a relationship between cellular response (effect) and morphological characteristics (likely cause) of nvPM [non-volatile particulate matter] from aircraft turbine engines,” the researchers concluded.
They believe that further research is needed to elucidate the full impact of aviation particulate matter on human health.
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