Greenhouse Gas Standard Reference Material (image) National Institute of Standards and Technology (NIST) Share Print E-Mail Caption Standard Reference Material 1720 (Northern Continental Air), is based on samples collected in the Rocky Mountains. Credit NIST/Bob Watters Usage Restrictions Please credit NIST/Bob Watters when using this image. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.