pH is a logarithmic scale decreased by roughly 30 percent Ph (acidity) scale is logarithmic A primer on pH http://pmel.noaa.gov/co2/story/A+primer+on+pH U.S. National Oceanic and Atmospheric Administration pH is a logarithmic scale A primer on pH pH is a logarithmic scale A Primer on pH (HS) it also has a lower pH decreased by roughly 30 percent http://www.pmel.noaa.gov/co2/story/A+primer+on+pH U.S. National Oceanic and Atmospheric Administration NOAA decreased by roughly 30 percent NOAA primer on pH pH is a logarithmic scale Ph (acidity) scale is logarithmic