San Francisco, Aug 15 : Google's smart speaker Nest Hub will warn users about air pollution and smoke in their vicinity so that they can take precautionary measures. Starting with the US and soon to be available in select markets, the new AQI (Air Quality Index) badge is included in the clock/weather widget in Nest Hubs. "Between wildfire season and recent increased efforts to reduce air pollution, it's more important than ever to know about the air quality in your area. That's why, we've added Air Quality information to the Ambient screen on Nest Hubs so you can stay informed with just a glance," Google said in an update. The air quality data comes from the US Environmental Protection Agency (EPA), which rates air quality on a scale from zero to 500, with zero being the best air quality. The users can ask "What's the air quality near me?" as a voice command and they will get alerts when the air quality drops to an unhealthy level or unhealthy for sensitive groups. The EPA uses the US AQI to report air quality, which includes a number value from zeroÂ?500 and an easy-to-learn colour scheme so you can quickly know if there are any concerns about the current air quality status. Higher values mean greater air pollution, and each colour represents a general quality category: Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous. "Air quality will roll out to Nest displays over the coming weeks, and you can control related notifications or opt-out of seeing the AQI badge in your display's settings at any time," said Google. /IANS