Exposure to high quantities of smoke (from vehicle exhaust pipe fumes and similar cases) can cause deposits to buildup over time on telescope lenses and even create a film that blurs the scope's views. If the garage becomes the necessary storage place, make sure to keep the dust caps on and consistently wipe down your equipment. Dust is pretty much unavoidable anywhere, however, if you can limit low ventilation areas, such as an attic, you can prevent excessive dust accumulation.