LEED impact categories are the environmental, social, and economic issues that LEED projects aim to address1. They provide an overview of the market transformation that technical requirements work to achieve, as well as a guide to where points should be assigned2. The categories focus on LEED's social, environmental, and economic goals, and they assess each strategy based on its ability to achieve those goals3.

ASHRAE developed the MERV scale, which rates air filter efficiency in capturing airborne particles. LEED references MERV ratings in Indoor Environmental Quality credits to ensure air quality.

Soft surfaces contribute to a comfortable acoustic environment by absorbing sound waves and reducing noise levels. This can include items such as carpets, upholstered furniture, and acoustic ceiling tiles. In contrast, hard surfaces (like wood cabinets, hollow metal doors, or glass partitions)can reflect sound waves and increase noise levels. References: LEED Green Associate Candidate Handbook, U.S. Green Building Council resources

The cradle-to-cradle approach to sustainable materials evaluates building materials from extraction to reuse, which means that the materials are considered as part of a continuous cycle of use and regeneration, rather than a linear process of consumption and disposal. The cradle-to-cradle approach aims to eliminate waste and pollution, conserve resources and energy, and create positive impacts for the environment and human health. The cradle-to-cradle approach is based on the principles of eco-effectiveness, which include designing products and systems that are safe and healthy for humans and nature, using renewable energy and clean water, celebrating diversity and creativity, and respecting social and environmental justice12. The cradle-to- cradle approach is also recognized and encouraged by LEED v4, which includes a credit for using products that have achieved Cradle to Cradle certification34.

LEED allows flexibility:
"If a project has overlapping eligibility, the project team must choose the rating system that best aligns with the majority of the project scope." The team determines applicability based on scope and use.