Keep the car mats clean, dust doesn't cause any smell but sometimes other things stick to them through shoe soles which cause bad smell.
Make sure carpet of car remain dry. Wet carpets cause bad smell when windows are closed.
Try using ionizer (cigarette lighter socket type), it keeps the atmosphere free from odors. Never keep spray cans in car, instead, small roll-ons (itar - also available in different perfumes) are good as they are small glass bottles, non-alcholic and no hazard of spilling.