How many strategies must be achieved to earn the IAQ Enhanced Air Quality Strategies credit?

To earn the Indoor Air Quality (IAQ) Enhanced Air Quality Strategies credit in LEED V4, a project must achieve both strategies from Option 1 and one additional strategy from Option 2. This requirement is designed to enhance indoor air quality beyond the basic standards, prompting more comprehensive measures for better ventilation, filtration, and overall air quality for building occupants.

By requiring both strategies from Option 1, the expectation is that projects implement foundational practices such as increased ventilation or superior air filtration systems. Adding one more strategy from Option 2 emphasizes the importance of additional measures, which could include enhanced pollutant control or use of low-emitting materials, thereby promoting a healthier indoor environment.

The options in the question reflect a range of potential combinations of strategies that could be pursued, but only the option requiring both strategies from Option 1 and one from Option 2 aligns with the credit's intent to significantly improve indoor air quality. This comprehensive approach ensures that various aspects of indoor air quality are adequately addressed, fostering better health and comfort for occupants.