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 Air Quality icon is made in flat color style
. This format was developed by Icons8 designer team and became immensely popular for use in web and mobile applications. Feel free to download this icon in PNG format for free, or unlock other formats for $5. Unlike other icon packs that have merely hundreds of icons, this monster icon pack contains 5,900 icons, all in the same style and quality.