In reference to the article on toxic schools, I just recently read in "Naturally Clean" by Hollender, that certain plants can be helpful in cleaning the air.  Plants that are recommended are:
boston fern (the overall best in purifying performance)
areca palm
bamboo palm
rubber plant
english ivy (excels at removing formaldehyde)
peace lily ( removes formald.,alcohols, acetone, benzene & trichloroethylene)
and even schefflera, spider plant & weeping fig were on the list.
Hope that helps.  It's certainly a very GREEN way to clean our air!  :)