Perhaps you should try some spelling variations:
"pollutants dispersion reduction" » "pollutant dispersion reduction", "pollution dispersion reduction", "pollutants detection reduction", "pollutants dispersion prediction", "pollutants dispersion predictions", "pollutants dimension reduction"
"pollutant diffusion reflection" » "pollutant discussion reflection", "pollutant diffusion reaction", "pollutant diffuse reflection", "pollutant dispersion reflection", "constant diffusion reflection"

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: (("pollutant diffusion reflection") OR ("pollutants dispersion reduction")).
• Removing quotes may allow a broader search: (( pollutant diffusion reflection ) or ( pollutants dispersion reduction )).
• Adding a wildcard symbol may retrieve word variants: (("pollutant diffusion reflection") or ("pollutants dispersion reduction"))*.