The feeling of opening the window and breathing the fresh air coming in is arguably one of the best feeling ever, however, how does someone know if the air is actually clean or not? The fact is that you would not know. According to the World Health Organization and American Lung Association, polluted outdoor air accounted for 4.6 million deaths in 2016, in the U.S. nearly 134 million people (over 40 percent of the population) are at risk of disease and premature death, moreover, indoor smoke is also a critical threat to 3 billion people who cook and heat by burning biomass, kerosene, and…