Original sentence: Air quality is another major concern.Barcelona shares various environmental problems with other major cities.Barcelona’s location (the city is hemmed in by the coastal mountain range) and its light regime of summer winds exacerbate the problem.Data cited by the Barcelona Field Studies Centre reveals that 65% of the city's population is subject to over 65 decibels of noise throughout the day (0800 - 2200 hours) and a further 35% to between 55 and 65 decibels  – levels that produce long-term damage to health.During the summer, it is estimated that over 66% of Barcelona's population is exposed to ozone levels in excess of 180ug/m3, and over 66% of the population are exposed to NO2 levels in excess of 200 um/m3.One of these is noise.The high levels of air pollutants over the northeastern Iberian Peninsula in summer have a strong influence both on ecosystems and on human health