Noise from roads, airports and equipment like leaf blowers has been linked with serious health impacts. Decades ago, the U.S. government passed a law limiting it, but it has no teeth.
Operators must begin installing new directional speaker systems or use in-ear listening devices.
More than 100 trolley tour buses would undergo equipment modifications to limit noise spillover.
A drop in shipping traffic is reducing underwater noise, so scientists are listening for how whales and other marine life are responding.
