Hey readers, yesterday SmartShanghai briefly published an article that compared Smart Air, a company that sells DIY purifiers, to a Blue Air model. It was soon brought to my attention that the filter we used in our test was in fact not theirs. Due to this error on our part, we've removed the article. Although I did recommend readers to buy Smart Air purifiers, the article negatively portrayed the purifier's filtering abilities against the Blue Air model. We take back those claims and sincerely apologize for the mistake. At the same time, I'd like to continue to recommend Smart Air as a great air purification solution at an affordable cost.