The big "issue" with formildihyde and the Katrina trailers wasn't the amount of off gasing, it was education and and follow though.
FEMA put these trailer in the open SUN, in AUGUST,in Louisana,southern Mississippi, Alabama, and Texas and told the people to turn OFF the air conditioners and open the windows! At best the inside temps would have been in the upper 90s. How many elderly or families with small children would do that for very long? So the A/C came on and the Formaldihyde gas just circulated through the trailer day and night.