20Open questions and known gaps
The short version: What we looked for and could not pin down well enough to print. If you can source any of it, the corrections desk below wants to hear from you.
Still digging
22 things we could not source well enough
Each of these would make the guide better. Send a source and we will add it, with credit if you want it.
- Population-wide prevalence of hyperacusis from a neutral clinical source
- An independent critical review of the evidence linking noise to heart disease
- Accuracy studies of phone sound meter apps on newer phones from the 2020s
- Whether EPA has appealed the July 2026 Quiet Communities v. EPA ruling, and any remedy order since
- The year Boston adopted its first noise ordinance and its first Air Pollution Control Commission noise regulations
- The final 2026 NSW restricted hours for air conditioners and pool/spa pumps
- When UK emergency services moved from two-tone horns to electronic wail and yelp sirens
- Sound output figures in the SAE J1849 emergency vehicle siren standard
- Whether Boston or Massachusetts runs outdoor warning sirens and on what test schedule
- How many Boston intersections have accessible pedestrian signals and which types
- How loud a truck engine brake is with a legal muffler versus a straight pipe, in measured dBA
- Measured decibel benefit of rail grinding on curve squeal specifically
- Recent MBTA subway platform noise measurements
- Boston's own leaf blower rules, if any, from a City of Boston source
- Measured sound level of a typical commercial rooftop HVAC unit at a stated distance
- EU-wide rules on vehicle reverse alarms, and any city that requires broadband alarms for night work
- UK hours or limits for garden equipment such as mowers and leaf blowers
- Whether MassDEP finalized its revised noise policy after the April 30, 2026 comment deadline
- Current Massport residential sound insulation totals, cost and eligibility contour
- Measured decibel level of the Boston July 4 howitzers or fireworks
- A named source making the developer and resident case against the agent of change principle
- Dawn chorus timing or level measurements for a US city such as Boston