ACID DEPOSITION ONTO NATURE AREAS IN THE NETHERLANDS .2. THROUGHFALL MEASUREMENTS COMPARED TO DEPOSITION ESTIMATES

In this study of acid depositions to Netherlands forests, measurements of acidifying components in throughfall were compared to estimates derived using the inferential method. Throughfall measurements were corrected for sea salt and other neutral salt deposition as well as for dry deposition of gases and aerosols to open sampler funnels. Corrected throughfall values for SO4, NH4 and total potential acid agreed better than uncorrected with inference estimates; corrections had almost no effect on NO3 values. Although corrected SO4 throughfall values are well correlated (0.82) with inference estimates, they are almost twice as high. For NO3 and NH4 correlation is poor; NO3 throughfall values are about half as high as inference estimates, NH4 inference estimates were higher or lower than corrected throughfall values. There was reasonable agreement between total potential acid deposition values from the two methods.