"The Devil's Hair Dryer," from City Lab

In November 2016, at the City Lab site, David Dudley wrote about the noise effects of two-stroke engines, mainly through the increasing use of two-stroke gas-powered leafblowers. Sample:

Other people who tend to complain about leaf blowers live next to (or attend) schools and universities, which doesn’t bode well for the quality of the learning going on in there. “Anecdotally, there are many teachers who have written to me discussing how campus lawn and garden maintenance activities disrupt their classroom instruction,” Walker tells me via email. “Some have had to stop class because students can’t hear their lecture.”
Noise pollution is particularly harmful for children, as decades of public health studies have demonstrated, and most efforts to silence the din of gas-powered blowers have focused on their auditory toll. Campaigns to forbid leaf blowers have been successfully waged from Long Island to South Pasadena*, many led by a national nonprofit, Quiet Communities, which has a mission to “promote clean, sustainable, and quiet outdoor maintenance practices.” One progressive solution proffered by commercial landscapers with eco-minded clients: high-tech battery-powered blowers like this bad boy, which costs as much as a (crappy) used car and runs for an hour on its lithium battery, but makes a bit less noise and a lot less smog.

He also added this chart, from the latest Greater Boston Noise report, of incidence of complaints: