Neighbors smoking is smelling up my house

Noel
I'm at my wits end. 
My neighbors smoke out on their deck which is about 20 ft from my bedroom. It smells up my room and all of my clothes. I've used air fresheners, ozone airater, scentsy warmer, candles and more. Nothing is helping! 
My Windows are closed and yet it still gets in. I'm 7 months pregnant, I'm an asthmatic, my husband has bad sleep apnea (I'm sure the occasional smoke smell doesn't help) and on top of that our daughter sleeps in the same room. I have to shampoo my carpets every 2 weeks, wash our bedding every other day and wash my walls weekly. At what point would you start letting your neighbors know how bothersome this is? And is there any legal action I can take? I mean it is decreasing the value of my home, potentially giving us second hand cancer, causing me to spend more money on asthma medication and costing me a fortune to continue cleaning! Let me know how you all would handle this because I'm ready to flip out and I know that won't do anything to help the situation. And if anyone knows any good ways to help keep the smoke out please share!