Amazon has just put its Alexa-compatible Smart Air Quality Monitor on sale for $41.99 for Prime Day, which is 40% off the regular price of $69.99. This is a lightning deal, which means only a certain number of units are going to be available at this price before it sells out. This is only the second time the Amazon Air Quality Monitor has ever been on sale, with the first sale being $14 higher than the deal today. This air monitor was released this past November and can keep track of particulate matter (PM), volatile organic compounds (VOCs), carbon monoxide (CO), humidity, and temperature. An LED on top shines green, yellow, and red to indicate the current air quality. For historical or more detailed info about your air quality, you can check the available reports in the Alexa app or you can just ask Alexa through a paired Echo device.