Atmospheric CO2 reading for week beginning April 5 was 403.42 parts per million (ppm).
Weekly value one year ago was 401.22 ppm
Weekly value 10 years ago was 382.26
Records are kept daily by the Scripps Institution of Oceanograpy at the University of California, San Diego, measurement made at Mauna Loa in Hawaii. Graph comes from the Scripps web page.
Go to https://scripps.ucsd.edu/programs/keelingcurve