It's a logo of a rectangle in portrait orientation with curved edges. Coming through the rectangle from left to right are curved line waves. There are three of them and they curve down then up then down.
This is a Air Quality icon. We've made it in iOS style
, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,300 icons, all in the same style and quality.