Dust burst

You create a small dust cloud. The size of the dust cloud can be any size up-to what can fit inside two 5-foot cubes (or up to 250 square feet) and can be formed into simple shapes. If the dust you summon fills a 5-foot cube that area is considered lightly obscured. Areas of dust must be connected but can be placed above of each other but no more than 10 feet high. At higher levels you can increase the size of the dust cloud you can summon as well as how far away you can summon it. Dust can be dissipated or moved with a light gust or breeze, like the gust cantrip or the gust of wind spell, but only in the area that can be hit by the spell. Also this spell cannot be summoned in rain, snow, or hail and will be dispelled by suck weather effects or spells that cause those effects.

If you cast this spell in an area that already has the lightly obscured effect that is not from this spell or a similar effect, such as an area that is dimly lit, it will create an area that is heavily obscured to any creature that does not have a way to see through one or both of the lightly obscured effects. Having dark-vision will let one see through the dim-light making it only lightly obscured from the dust.

Level 5 create enough dust to fill 4 5X5 cubes (about 500 square feet) up to 10 feet away . level 11 create enough dust to fill 6 5X5 cubes (about 750 square feet) up to 15 feet away. Level 17 create enough dust to fill 8 5X5 cubes (about 1000 square feet) up to 20 feet away.

Alternatively, if you don't want the spell to level just use the level 17 effect.