For airports in populated areas, it is common to implement noise abatement procedures. In practice, this means that aircraft reduce thrust on departure, so that noise is reduced in proximity to the airport.
However, this does mean that aircraft spend a longer time at a lower altitude, which may be bad news for populated areas further away from the airport. I am wondering how noise abatement procedures affect areas further away, up to 150km away from the airport. I would like to know how this compares quantitatively (e.g., a dB(A) chart like below, for larger distances) between procedures.
Image: Hamamci et al. (2017). Determining characteristics of lands affected by noise pollution of airports. Fresenius Environmental Bulletin. 26. 69-74.