M12 ranges from 20 to
60 ppbv over most continental regions with higher exposures
(>70 ppbv) limited to northern India, eastern China, and parts of
the southern U.S. AOT40 is most reduced compared to the A2
scenario in the U.S., Europe, and the Middle East (Fig. 2); however,
AOT40 in the B1 scenario still remains largely above the 3 ppmh
“critical level” established in Europe for the protection of crops