The first helicopter thundered overhead at 8:05 a.m., as Christine Reekie was sipping her morning coffee. Another one came a minute later, and another, and another, and yet another, swooping so low she feared it would not clear the transmission lines. Ms. Reekie had suffered a small stroke two years earlier, and now she shakily began noting each flyover in writing. By noon, she had counted 14, as they jetted to and from the Hamptons right over her home in Floral Park, just over the border from Queens on Long Island.

Fifteen miles due west, in Brooklyn Heights, Roberto Gautier greeted the bathroom mirror with bloodshot eyes. For the umpteenth night running, jackhammering on the Brooklyn Bridge 23 stories below had kept him up until dawn. An aged neighbor appeared at his door, distraught about the racket, having forgotten that she had come knocking the night before. Mr. Gautier’s wife had arranged to stay at a friend’s house because she could no longer focus at work.

“We’re at the breaking point,” Mr. Gautier said.

Silence has become a luxury in New York that only a scant few can truly afford, and cultural, technological and economic changes in recent years have added to the din everyone else must endure, creating not just one culprit, but many.

Giant rooftop heating and ventilation units confront residents of the newly built high-rises that face them, and the higher the apartment, the more exposed it is to city noise. Fresh Direct trucks with droning refrigeration units thrum in the streets. Home theater systems thump through walls that have grown thinner with newer construction, and noise reverberates along and through floor-to-ceiling glass walls. Helicopters crowd the skies. Planes fly new routes over fresh new tracts of homes, ferrying overnight cargo ordered by online shoppers. Clamorous new neighborhoods exist in places that were once either empty or served as industrial zones that were quiet at night. Citywide building permits are at their highest in five years, with more crews permitted to work through the night.

Noise has become harder than ever to escape, though New York City, now in its second century of noise abatement efforts, has managed to quiet some offenders of the past, like boom boxes and car alarms. Interviews with residents in affected areas, officials, soundproofing professionals and audio experts not only confirm the creep in round-the-clock outside noise, but suggest that its potential ill effects can rival those caused by deliberately manipulated, high-decibel assaults inside stores, clubs and restaurants. Some contend that the city, despite its efforts, has shown a distinct reluctance to crack down on certain offenders, like construction companies, especially in recent years.

“It’s categorically the case that we have more constant and geographically pervasive exposure to noise,” said George Prochnik, the Brooklyn-based author of “In Pursuit of Silence: Listening for Meaning in a World of Noise,” which explores the ill effects of omnipresent sound. “We can simply look where there were undeveloped spaces and noncommercial spaces, less intense transportation, less commercial activity, and all of these things bring with them noise.”