Info from their website: 

Indoor air quality is an important issue because most people spend as much as 90% of their time indoors at home, work, or school. Poor indoor air quality can be caused by a number of factors, including inadequate ventilation, poor cleaning, and excessive emissions of volatile organic compounds.

The FloorScore® program, developed by the Resilient Floor Covering Institute (RFCI) in conjunction with Scientific Certification Systems (SCS), tests and certifies flooring products for compliance with indoor air quality emission requirements adopted nation-wide. Flooring products include vinyl, polymeric flooring, linoleum, laminate flooring, engineered hardwood flooring, ceramic flooring, rubber flooring, wall base and stair tread, and associated sundries. A flooring product bearing the FloorScore® seal has been independently certified by SCS to comply with the volatile organic compound emissions criteria of the California Section 01350 standard. These flooring products qualify for use in high performance schools and office buildings. Thus, products with the FloorScore® seal have passed a third party certification process and are recognized as contributing to good indoor air quality in order to protect human health.

It’s not an issue of simply measuring total VOCs in the air you’re breathing. What matters is the nature of particular VOCs that may be in the air.