"Lluvias ácidas." . . "Acid rain" . . "Acid rain." . "Research" . . "Kvælstof" . . "Oxider" . . "Vegetation" . . "Air pollution" . . "Sur nedbør" . . "Acidification de l'environnement." . . "Forskning" . . "Syrning, forsuring" . . "Afsætning" . . "USA" . . . . "Etats-Unis d'Amérique." . . "Saurer Regen." . . "Luftforurening" . . "Svovl" . . "Transport" . . "Deposition" . . "Pioggia acida." . . "Pluie." . . "Nitrogen" . . . . . . . . . . . . . . . . . . . . . . . . . . . "Acid rain information book" . "Acid rain information book"@en . . . . . . . . . . . . . . . . . . . . . . . . . "Overvågning, kontrol, monitering" . . "Acidification" . . "Sulphur" . . "Monitoring" . . "USA." . . "Pluies acides." . . "Oxides" . .