The first report was recently issued on ambient levels of glyphosate and its major degradation product, aminomethylphosphonic acid (AMPA), in air and rain. Glyphosate is the most widely used herbicide in the U.S.
Weekly air particle and rain samples were collected during two growing seasons in agricultural areas in Mississippi and Iowa. Rain was also collected in Indiana. The frequency of glyphosate detection ranged from 60 to 100 percent in both air and rain.
According to the report, as linked on the website Green Med Info:
“The frequency of detection and median and maximum concentrations of glyphosate in air were similar or greater to those of the other high-use herbicides observed in the Mississippi River basin, whereas its concentration in rain was greater than the other herbicides.”