Sampling Air on the Continental Divide (IMAGE) NOAA Headquarters Caption CIRES scientist Duane Kitzis approaches the air sampling station on Niwot Ridge, Colorado, part of NOAA's Global Greenhouse Gas Reference Network, in this 2017 photo. The first air sample analyzed for carbon-14 as part of research into a new method of estimating fossil fuel emissions from ambient air was collected here in 2003. Credit James Murnan, NOAA Usage Restrictions None License Licensed content 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.