While we're unlikely to get atmospheric CO2 concentrations down as low as they were (275 ppm) before we started pumping pollution skyward during the Industrial Revolution, climate scientists and green leaders agree that 350 ppm would be a tolerable upper limit. (scientificamerican.com)
Most men, women and children in Canada exceed the tolerable upper limits of salt for their bodies. (theconversation.com)
Dr. Vieth argues that 4,000 IU of vitamin D per day is safe even if one obtains an additional 4,000 IU per day from sunlight, 33 while the Institute of Medicine has set the tolerable upper limit at 2,000 IU per day. (westonaprice.org)