Trends in atmospheric concentrations of CO2 (ppm), CH4 (ppb) and N2O (ppb), between 1800 and 2017 — European Environment Agency
![MWD of SoCal on Twitter: "MWD measures water levels in very tiny quantities (parts per million, per billion, or per trillion) #NationalWaterQualityMonth https://t.co/EkL3eJINeE" / Twitter MWD of SoCal on Twitter: "MWD measures water levels in very tiny quantities (parts per million, per billion, or per trillion) #NationalWaterQualityMonth https://t.co/EkL3eJINeE" / Twitter](https://pbs.twimg.com/media/DIaAXkjVYAQ177g.jpg:large)
MWD of SoCal on Twitter: "MWD measures water levels in very tiny quantities (parts per million, per billion, or per trillion) #NationalWaterQualityMonth https://t.co/EkL3eJINeE" / Twitter
![Leto Atreides on Twitter: "i only pretend to understand what parts per million (ppm) means. parts per million WHAT?" / Twitter Leto Atreides on Twitter: "i only pretend to understand what parts per million (ppm) means. parts per million WHAT?" / Twitter](https://pbs.twimg.com/media/Efp04xOXYAAs3BC.jpg)