There are health consequences of elevated sound levels. Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. Although some hearing loss occurs naturally with age,[2] in many developed nations the impact of noise is sufficient to impair hearing over the course of a lifetime.[3][4] Elevated noise levels can create stress, increase workplace accident rates, and stimulate aggression and other anti-social behaviors.[5]
A large-scale statistical analysis of the health effects of aircraft noise was undertaken in the late 2000s by Bernhard Greiser for the Umweltbundesamt, Germany's central environmental office. The health data of over one million residents around the Cologne airport were analysed for health effects correlating with aircraft noise. The results were then corrected for other noise influences in the residential areas, and for socioeconomic factors, to reduce possible skewing of the data. The study concluded that aircraft noise clearly and significantly impairs health, with, for example, a day-time average sound pressure level of 60 decibel increasing coronary heart disease by 61% in men and 80% in women. As another indicator, a night-time average sound pressure level of 55 decibel increased the risk of heart attacks by 66% in men and 139% in women. Statistically significant health effects did however start as early as from an average sound pressure level of 40 decibel.[6]

Source: http://en.wikipedia.org/wiki/Aircraft_noise#Noise_from_aircraft_systems