The UL GreenGuard Gold certification means that this product helps maintain healthy indoor air quality (IAQ). UL GreenGuard-certified products are tested for over 15,000 VOCs (volatile organic compounds) that pollute indoor air and can cause a wide variety of health problems including dizziness and headaches (long-term exposure to VOCs can also cause cancer). Products with a GreenGuard Gold certification have less than 360 VOCs, so you can be sure that they will minimize the number of harmful pollutants in your space.