There was a thread on HN around a week ago around just this topic. Well worth reading through it "Build a do-it-yourself home air purifier for about $25" for th

There was a thread on HN around a week ago around just this topic. Well worth reading through it "Build a do-it-yourself home air purifier for about $25" for the comments on filters and sensors. [1]. [1] https://news.ycombinator.com/item?id=18445652 https://news.ycombinator.com/item?id=18445652