Independent app volume control in iOS for iPhone..

I enjoy listening to audiobooks while playing games on my iPhone but am constantly having problems with the music (mainly from ads) blasting at a painful level. I mute the games internally but this doesn’t carry over to the ads. Is there any setting or app that I can get that will allow me to adjust the volume on an app by app basis including any ads spawned by that app? If not can anyone suggest a way to mute or at least reduce the volume of these horribly invasive ads?