Try air push detector app and run it even tho it say you may not need to. Or try installing all new apps and reinstalling one at a time to see which is bringing the ads with it. This usually happens with free apps or paid app that have a free trial to get you to pay for the app since the ads are annoying. If you can't find the offending app I would do a factory data reset and install apps one at a time after that to see which is the culprit.