Time-to-time See The Air readers contact me because they want to know if some portable Air Quality monitors made in China worth an investment, so I decided to research and find out which of them is the best. First, I cross checked the features as they were presented online and I noticed that some of them have a laser Particulate Matter PM2.5 sensor, which is good, and some other use an optical one. With that in mind, I purchased the WP6930S.
