Residential buildings up to 3 stories in height shall have filters with Minimum Efficiency Reporting Value (MERV) of 6. Residential buildings over 3 stories in height have no requirements for MERV values. All non-residential buildings shall have filters with a MERV rating of at least 8. All buildings residential and commercial of any height located within 1000 feet of a freeway shall have filters with a MERV value of at least 13.