This so-called study is air quality fraud. It's so bad I thought twice about including a link to it. The study starts with the assumption that tiny particles in the atmosphere cause asthma in children. No proof of that assumption is presented. In fact, the origin of childhood asthma is unknown. No study where humans were exposed to air pollutants has ever triggered an asthmatic reaction.
If you wanted to study childhood asthma, you would need to know the following for each child: Time spent outside, air quality outside, time spent indoors, air quality indoors. That information is not available, so wild guessing and computer models atr used.
The time each child actually spent outdoors is unknown. The actual quality of the air each child was exposed to outdoors is unknown. Local outdoor air quality reading proxies, are used and assumptions (wild guesses) are made about outdoors exposure. The study does NOT have any indoor air quality data, where children spend almost all of their time.
The study results in zero correlation between estimated air quality and asthma in the children studied. No one would have cared about those non-results. So the authors manipulated the actual results by sample size, and other tricks, into a weak statistical association.
