Question about my mom watching my baby when I go back to work?

Hello ladies, well im having my baby Wednesday. I will be home with her for 2 months, but after that I need to go back to work. My mom will have to watch her 3 days a week. And im kinda worried because my mom isn't the greatest house keeper. Her house is very dusty because she never airs it out. She says that the outside gives everyone asthma. Which I think is the house not being too clean outside air is good. Theres dod hair everywhere and I dont wanna be a jerk but I hate her house its so dank and dark they live like hermits. I am the opposite my husband and I have a very airy clean house. And im worried that when she watches her she might get sick. When I go over to her house I get congested and sneezy. I dont want to put her in day care. But I dont know how to tell my mom she needs to tidy up her house a lot! I dont wanna hurt her feelings, but I need to take care of my baby first. So any suggestions on how to tell her this? Thanks.