Perhaps you should try some spelling variations:
"dioxin emissions" » "dioxide emissions", "dioxide emission", "down emissions"
"photon emissions" » "photon emission", "phonon emission", "photo emission"
"toxic emissions" » "atomic emission", "oxide emissions", "voc emissions"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("toxic emissions") OR ((("dioxin emissions") OR ("photon emissions"))))*.
• Removing quotes may allow a broader search: (( toxic emissions ) or ((( dioxin emissions ) or ( photon emissions ))))*.