The project is 70-unit condo building with high efficient residential split systems. Natural ventilation is provided to the condo units via operable windows, and mechanical ventilation is provided to the corridors via two commercial rooftop units. The third part of the requirement for EQ 5 requires MERV 13 or better filtration on all building HVAC systems serving regularly occupied spaces. The residential split system equipment cannot physically handle the MERV 13 filters due to filter size and increased air pressure drop across the filter. The corridor supply units, which are commercial grade, can and will be provided with MERV 13 filters. The project design will also meet both of the other requirements for this credit for the entryway systems and chemical and pollutant exhaust and control. We have reviewed LEED NC v2.1 and the LEED for Homes program for their Indoor Chemical & Pollutant Source Control credits. LEED NC 2.1 EQ5 did not have any filtration requirements and therefore no CIR\'s to review to determine options for the residential split systems. The LEED for Homes scoring system breaks the Indoor Chemical & Pollutant Source Control into two separate credits: IEQ7 Supply Air Filtering and IEQ8 Contaminant Control. The filtration requirements are fully covered under IEQ7 which provides a mandatory requirement of installing MERV 8 filtration and MERV 10 filtration to obtain one point. We also reviewed the 2004 ASHRAE Handbook, HVAC Systems and Equipment, Chapter 24, Table 3, which lists the various MERV filtration levels and typical applications and limitations. MERV 1 - 4 provide minimum filtration levels for residential. MERV 5 - 8 are filtration levels for typical commercial buildings and better residential. MERV 9 - 12 are filtration levels for Superior residential and better commercial buildings along with hospital laboratories. MERV 13 - 16 are filtration levels for Superior commercial buildings, general surgery and hospital inpatient care. These levels demonstrate that the MERV 13 is geared toward a commercial building and not realistic, nor feasible, as a requirement for residential DX split systems to achieve this credit. Based on ASHRAE Handbook\'s tables and listings, and the LEED for Homes requirements, we propose to meet this credit by providing MERV 10 filters on all residential split systems and MERV 13 filters on the commercial rooftops serving the corridors. These filtration levels are providing the best filtration levels that the systems can accommodate and mitigating the amount of contaminants that occupants are exposed to. We feel that our proposed modification follows the intent of the credit while adapting it to a practical, and still superior, use for a residential application.