Could the sounds of aircraft significantly impact health?
In 2013, there were 64 million take-offs and landings - a 1.2 percent rise from 2012.
The International Civil Aviation Organization believe that this figure is likely to double in the next 2 decades.
With airports multiplying and expanding, more and more people are exposed to aircraft noise on a regular basis.
Exposure has previously been associated with sleep disturbances, breathing problems during the night, and nervousness.
Emerging research suggests that aircraft noise might have significant physical effects on individuals who are subjected to the highest levels of noise.
Similarly, a study using data from more than 6 million individuals, published in The BMJ in 2013, found that individuals who lived in areas with the highest levels of noise exposure had a 3.5 percent increased cardiovascular hospital admission rate.
Aircraft noise and health revisited
New data on this topic was presented this week at the EuroPRevent 2016 meeting by Marta Rojek, from Jagiellonian University Medical College in Krakow, Poland. Rojek and her team investigated aircraft noise and its effect on hypertension and asymptomatic organ damage.
The team used 201 adults aged 40-66, all of whom lived in a region with either low or high aircraft noise for the past 3 years. Of this group, 101 regularly experienced aircraft sounds of 60 decibels or more, and the remaining 100 lived in an area experiencing sounds of 55 decibels or less - these were the control group.
The subjects were all paired by age, gender, and the amount of time they had lived in the area. The individuals' blood pressure was measured, as was the stiffness of their aorta and the mass and function of the heart's left ventricle (one of the heart's four chambers).
Aortic stiffness is a marker for biological aging and is associated with an increased risk of cardiovascular events, such as stroke and myocardial infarction.
As expected, those living nearest to airports, and enduring the highest air traffic noises, fared least well. Individuals living in an area where there was greater air traffic noise had increased hypertension, when compared with those who lived in quieter areas - 40 percent and 24 percent, respectively.
The high-noise group had higher systolic and diastolic blood pressure than the control group (89 compared with 79 mm Hg). Similarly, when the researchers looked for signs of organ damage, they found that those living with higher levels of aircraft noise had stiffer aortas and higher ventricular mass.
"Our results suggest that living near an airport for 3 years or more is associated with an increased risk of high blood pressure and hypertension. These changes may then lead to damage of the aorta and heart which could increase the risk of having a heart attack."
How could noise cause health problems?
Although evidence for the detrimental effect of aircraft noise on human health is mounting, more research is needed before solid conclusions can be drawn. However, it seems clear that there are at least some physiological ramifications of living close to an airport.
This might be due to an increased release of stress hormones, which naturally raise blood pressure. Even as we sleep, extraneous noise enters our ears and is fed to our brains, potentially putting our body on "high alert."
There is legislation in place to help minimize the risks, but whether it is sufficient, globally, is up for debate. Rojek says: "European Union regulations say that countries must assess and manage environmental noise, and there are national laws on aircraft noise. [...] Noise can be kept below those levels by using only noise-certified aircraft, redirecting flight paths, keeping airports away from homes, and avoiding night flights."
As both air traffic and population numbers steadily increase, any negative health consequence of aircraft sound is likely to become more pronounced. Hopefully, research such as this will convince legislators to monitor and control how people are subjected to these sounds.