Use "dust down" em uma frase

1. The morning fog kept the dust down

2. The inside of my left eye started itching, and I wondered if it was the sawdust down there

3. The ground crews, which had to replace twenty-four dirt-clogged aircraft engines in twenty-one days, resorted to spraying oil on the taxiways to keep the dust down

4. On snow, trample it down firmly to prevent it swirling and, in dry areas, water the surface to keep the dust down