Muscat has dusty days as Leamington has fogs.
But aircraft operate normally on dusty days there, as they do on foggy days here.
This is a picture of the Burj Roundabout and Rusail shopping centre on a dusty day, taken from a Fokker Friendship about 2 miles from touchdown at Muscat-Seeb Airport. Such conditions were common - often the dust haze was much worse, and extended up several thousand feet. Temperatures were rarely much below 30 degrees C., and humidities usually 80% or more.
The dust is presumably mostly from sand, so it is silica, very abrasive.