Are the ads embedded into these pages or are they appearing as pop-ups?
If it's the former you can block them by using a decent browser (preferably Firefox) and the add-on which shall not be mentioned here by me ('cos the Ed doesn't like it) - but I see that AP has already done it anyway ;-)
If it's the latter you've got malware on your computer. Download, install and run the free version of Malwarebytes Anti-Malware to get rid of it:
https://www.malwarebytes.org/antimalware/
(NB: When installing, take great care to deselect the pre-ticked option to take a free trial of the Premium version).