With the alarming level of pollution in the city, there isn't any quick remedy to fix outdoor air quality. While you can put on masks when stepping out, you can use air purifiers indoors. But while buying one, consider a few things including the room size, the clean air delivery rate (CADR), air changes per hour (ACH) and the type of filter in the purifier, among other things. CADR is affected by room area and height. The CADR should ideally be two-thirds ...