the sound vanished

[alpacinoutd]

Are these good?

1. Cold air was blowing in through the window. She strode towards it, slammed it shut and turned the handle. The sounds of the noisy city vanished along with the cold, smoggy air.

2. They hiked until they reached the peak of the gentle mountain. Up there, they could see the vast city, thousands of specks of taillights melting together into flowing streams of red. But the sounds of the city had disappeared.

Also, what can I use instead of "the sounds of the city"?

[emsr2d2]

What's a "gentle mountain"?

[alpacinoutd]

What's a "gentle mountain"?

A mountain that looks nice and gentle. I mean it's not ragged and intimidating.

What about the rest of them?

[alpacinoutd]

Okay, let's look at them without gentle.

1. Cold air was blowing in through the window. She strode towards it, slammed it shut and turned the handle. The sounds of the noisy city vanished along with the cold, smoggy air.

2. They hiked until they reached the peak of the mountain. Up there, they could see the vast city, thousands of specks of taillights melting together into flowing streams of red. But the sounds of the city had disappeared. It was silent except for the hissing of a cold wind.

[Charlie Bernstein]

Are these good?

1. Cold air was blowing in through the window. She strode towards it, slammed it shut, and turned the handle. The noise of the city vanished along with the cold, smoggy air.

The smell probably wouldn't vanish as quickly as the cold. The it will take a few minutes for the room to warm up. Whether the smell of smog goes away depends on the kind of heating system the place has.

2. They hiked until they reached the peak of the gently sloping mountain. Up there, they could see the vast city, thousands of specks of taillights melting together into flowing streams of red. But the sounds of the city had disappeared.

Also, what can I use instead of "the sounds of the city"?

If the city were closer, then din would work. But from that distance, you might like drone.

[alpacinoutd]

The smell probably wouldn't vanish as quickly as the cold. The it will take a few minutes for the room to warm up. Whether the smell of smog goes away depends on the kind of heating system the place has. If the city were closer, then din would work. But from that distance, you might like drone.

Okay, what about now?

1. Cold air was blowing in through the window. She strode towards it, slammed it shut, and turned the handle. The noise of the city vanished, the cold smoggy air stopped streaming in.

2. They hiked until they reached the peak of the gently sloping mountain. Up there, they could see the vast city, thousands of specks of taillights melting together into flowing streams of red. But the drone of the city had disappeared.

[Charlie Bernstein]

Okay, what about now?

1. Cold air was blowing in through the window. She strode towards it, slammed it shut, and turned the handle. The noise of the city vanished, the cold smoggy air stopped streaming in.

2. They hiked until they reached the peak of the gently sloping mountain. Up there, they could see the vast city, thousands of specks of taillights melting together into flowing streams of red. But the drone of the city had disappeared.

It's good. You can probably get rid of "But."

PS: Don't change this in your example, but you can also say that sound faded.