You can try to wipe the plant with a damp towel, but you risk damaging it. These plants are very sensitive to touch and stress, so be careful. The best solution would be to restrict Pinguicula's access to the open air during the daytime when the greatest dust emission occurs. A few years ago, I also lived in a dirty neighborhood. A layer of dust formed on the house's white walls due to constantly passing cars and construction sites. I constantly turned to effective cleaning agents to keep the house in decent condition. I hope my advice will help you. Good luck!