Imagine that you own one perfect lawn, and that you will never be able to replace it. No new grass seed, no new sod; this is all you will ever have. How would you protect this patch of green? Would you allow a truck to ride roughshod across it?

In each inner ear we have “patches” of sensory hair cells that wave like grass, enabling us to hear sounds. We have 18,000 of these microscopic feelers in each ear — and they have to last our entire lives.

These hair cells can be permanently destroyed by loud sounds. Just as the tires of a big truck can rip up grass from a yard, big noises can bend and even break the hair cells. If they die, they do not grow back. And if enough of them are damaged, we can lose our ability to hear an entire frequency of sound. This is what we call noise-induced hearing loss.

“So what?” we might say. “I can get a hearing aid if that happens!” However, hearing aids only amplify sounds that we can already hear. They cannot magically heal dead hair cells and restore our lost frequencies.

How do we know when a sound is dangerously loud? Great question. Eighty-five decibels (dBA) is the number to remember.

We can be exposed to up to eight hours of 85 dBA without damage. This is the noise level we might hear at a busy street corner. For every three decibels above 85, our safe listening time is cut in half.

Using power tools, shooting guns, and listening to music are all common recreational activities that can generate some dangerous decibel levels. Here are some examples:

• Gas-powered lawn mower, hair dryer: 91 dBA (two hours max safe listening time)

• Rock concert, leaf blower, chainsaw: 109 dBA (less than two minutes max safe listening time)

• Fireworks, gun shot: 140 dBA (unsafe!)

According to these facts, if we choose to fire a gun once without wearing ear protection, then we are choosing to permanently damage our hearing. Just like letting a monster truck speed over our hypothetical lawn.

Also, longer periods of lower sound can be dangerous. If we use a gas-powered mower all day long without ear protection, we are choosing hearing loss. This would be like letting a Mini Cooper run slow wheelies repeatedly through your yard.

Here are three ways we can protect our remaining hearing for a lifetime:

• Walk away — Move away from the sound source.

• Turn it down — Turn down the volume of your music and television. At public events such as concerts, church services and fitness classes, sound technicians have a public health responsibility to keep venue noise levels safe.

• Protect your ears — Wear earmuffs or earplugs, or use your hands. Visit dangerousdecibels.org for more information on proper use.

The next time you see grass waving in the breeze, think about your own patches of “ear grass” and what you can do to protect them today.