I live in an apt complex, and I have one covered spot in an underground parking area. The problem is that the there is an open space all across the ceiling and the wall where light and air come through, and I'm fairly certain the landscapers/leaf blowers are running through there and blowing a bunch of crap into the garage every week. I've heard you aren't really supposed to use car covers because they just mar the dust into the car ... but is there a better way of dealing with this?

You shouldn't use a car cover on a DIRTY car. If your car is clean to start, then it sounds like that is exactly what you need.

Get a car cover, they work great. I keep mine close to the ocean and it's made a big difference keeping it clean.

Or just get a latter and put some really fine mesh or completely block the opening above your car to prevent the issue. (maybe just block in from the outside.)

Depending on the color of your car, a california duster can work wonders.

i wouldn't use a duster if the car gets dirt blown on it. duster works well for fine dust but may scratch the paint in his situation.

your best bet is to ask the management to address this with the landscaper.

Here's another suggestion - tell your association manager of the problem and have them address it with the landscape vendor. It probably causes a problem for your building staff to have to deal with crap being blown into the garage as it is.