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Why Do Leaf Blower Operators Insist on Constantly Revving Their Engines?

Running a leaf blower is about as loud as the hum of conversation in a typical (pre-COVID) restaurant—and between 7 pm and 7 am, it’s forbidden to operate them at all.

Is there anything to be done about the daily cacophony of leaf blowers? Their chain saw-like roaring mars Portland’s picturesque neighborhoods. Also, why do the operators insist on constantly revving their engines like motocross riders? —Chanon B.

I’m of two minds about how to respond to your letter, Chanon. Normally, I’d just call you a pampered bourgeois and tell you to suck it up. However, at the moment I’m nursing a hangover that just forced me to put two pillows over my head to escape the deafening roar from a bowl of Rice Krispies, so I’m more inclined than usual to sympathize with noise complaints.

Even so, you have to admit there are worse things than someone using a leaf blower in your neighborhood (someone using a leaf blower in my neighborhood, for example). If that chain saw-like roaring you decry were coming from an actual two-stroke chain saw, you’d be contending with a sound pressure level of 110 decibels—louder than most rock bands and capable of causing permanent hearing loss after just two minutes of unprotected exposure.

Leaf blowers, by contrast, are currently required by city ordinance to be no louder than 65 dB. That makes running a leaf blower about as loud as the hum of conversation in a typical (pre-COVID) restaurant—and between 7 pm and 7 am, it’s forbidden to operate them at all.

This apologia doesn’t explain why landscaper types are so fond of revving their engines, however. You could be forgiven for thinking they do it to be as loud as possible out of sheer spite. In fact, however, that sound means the operator is using the blower precisely as intended.

Revving the engine provides the power necessary for actually shifting the leaves. When the machine is idle—between sweeps, say, or when the operator is moving to another section of lawn—little power is needed, so the motor can run slower.

They’re not deliberately revving the engine to make more noise, they’re actually letting it spin down (whenever possible) to make less! How thoughtful! I bet you feel bad now for all the uncharitable thoughts you harbored toward these heroic leaf blower operators.

Don’t get too charitable, though—starting Nov. 1, the legal maximum volume for leaf blowers increases (as it does every winter) to 70 dB. My advice: Stay drunk till March.

Questions? Send them to dr.know@wweek.com.