The Noise

NIOSH recommends no more than 85 dBA averaged over 8 hours, with allowed time halving for every 3 dB louder. NIDCD says sounds at or below 70 dBA are unlikely to cause hearing loss even after long exposure.

Decibels are logarithmic, so +10 dB is ten times the sound energy. On average, people hear that tenfold energy increase as roughly a doubling of loudness, according to the Federal Highway Administration; a 3 dB change is barely perceptible.

Yes, the Noise Control Act of 1972 is still law, but Congress stopped funding EPA's noise office in 1981 and EPA dropped nearly all noise work. Day-to-day noise rules are set by states and especially cities. In July 2026 a federal judge found EPA had unlawfully neglected the Act, with remedies still to be decided.

A 1985 NIOSH field study measured an ambulance siren at 122 dBA at 10 feet and 98-105 dBA at 100 feet outside the vehicle. With roof speakers, the driver was exposed to 109 dBA; grille-mounted speakers cut that to 87 dBA.

In the FHWA's construction noise table, a jackhammer measured 89 dBA Lmax at 50 feet, against a specification limit of 85. Lmax is the peak level during the measurement, not an average.

In Europe, road traffic exposes the most people: the EEA counted about 100 million people at or above 55 dB Lden from roads in 2012, against 19 million from railways and more than 4.1 million from aircraft.

DNL is a yearly average of aircraft noise with a penalty for night flights. Under US federal guidance, homes, schools, hospitals and similar uses are considered incompatible with airport noise at or above 65 DNL, and everything below it is considered compatible.

The AAO-HNS says sound at US music venues commonly exceeds 100 dB. Audio Engineering Society research found front-row peaks above 140 dBC where subwoofers sat on the ground, while only a handful of engineers mixed above 103 dBA averaged over at least 5 minutes, usually briefly during encores.

Boston considers anything louder than 50 decibels from 11 p.m. to 7 a.m., or louder than 70 decibels at any time, unreasonable, except permitted construction. The APCC's zoning limits treat 7 a.m. to 6 p.m. Monday through Saturday as daytime, with stricter limits at all other hours, including all of Sunday.

NIOSH recommends no more than 15 minutes a day at 100 dBA; OSHA's legal workplace limit is 2 hours. NIDCD says damage is more likely after at least 14 minutes at that level.

dB on its own is a sound level with no frequency filter specified. dBA applies A-weighting, which turns down bass and very high treble to match human hearing, and it is the basic environmental noise measure used by EPA and most agencies.

Under New York City's Noise Code, construction is allowed on weekdays from 7 a.m. to 6 p.m. Owner-occupied one- or two-family homes may work weekends from 10 a.m. to 4 p.m. if more than 300 feet from a house of worship. Work outside those hours needs an after-hours authorization and a noise mitigation plan.

Both are rising-and-falling siren tones. The wail sweeps slowly; the yelp makes the same sweep much faster, and drivers switch between them as conditions change.

Those are broadband or 'white noise' backup alarms. OSHA said in 2004 that its rules do not require a single-tone alarm, and a white-noise alarm complies if it warns workers in time. Broadband sound gives the ear more cues for locating where it comes from.

Tires. For cars at steady speed, tire-pavement noise dominates above about 20 mph (32 km/h), according to the CP Tech Center; trucks cross over at higher speeds.

Possibly, through an airport's voluntary FAA Part 150 program. Airports map their 65 DNL contour and can propose home and school sound insulation; FAA-approved measures are eligible for Airport Improvement Program grants covering 80% of the cost.

WHO's voluntary 2022 Global standard for safe listening venues and events limits the average sound level to 100 dB LAeq over 15 minutes. It also calls for sound monitoring, better acoustics and sound systems, available hearing protection, quiet zones and staff training.

Regular construction hours are 7 a.m. to 6 p.m. on weekdays, with complaints going to Inspectional Services. After hours, check the city's after-hours permit database and call 311 or ISD if no permit exists.

NIOSH, the research agency, recommends 85 dBA over 8 hours with a 3 dB exchange rate. OSHA, the enforcement agency, sets a legal limit of 90 dBA over 8 hours with a 5 dB exchange rate, and requires a hearing conservation program at 85 dBA.

A 2014 NIOSH study found only three iOS apps within +/-2 dBA of a reference meter, and one Android app showed wide variance from phone to phone. The free iOS NIOSH Sound Level Meter app tested about 2 dBA off with the built-in mic and within 1 dBA with a calibrated external mic.

Commercial music may not exceed 42 dB(A) inside a neighbor's home, 45 dB in any one-third octave band from 63 to 500 Hz, or 6 dB(C) above ambient where ambient exceeds 62 dB(C). The rule is in section 24-231 of the code, in effect since July 1, 2007.

Germany legally allows only one emergency tone, the two-tone Martinshorn defined by DIN 14610. A 2022 petition to allow US-style wail and yelp ended in 2024 with yelp permitted only as a police and customs stop signal.

Gas leaf blowers typically measure 65-80 dBA at 50 feet and can exceed 100 dBA at the operator's ear, according to Fine Homebuilding. A 2018 study measured three gas models at 67-77 dBA at 50 feet.

For homes directly behind them, barriers cut about 5 to 10 dBA, which at the top of that range is roughly half as loud. Effectiveness drops off beyond about 300 to 500 feet (90 to 150 m) from the road.

Since the 2010s the FAA has moved many airports to satellite-guided RNAV routes that planes fly very precisely, concentrating flights over the same tracks. In Phoenix, new routes in 2014 brought more complaints in two weeks than in the prior year, and a federal court vacated them in 2017.

Under Decree 2017-1244, amplified sound anywhere the public has access is capped at 102 dB(A) and 118 dB(C), each averaged over 15 minutes. Events for children up to age 6 are capped at 94 dB(A) and 104 dB(C).