Monitoring of atmospheric wet and dry deposition
provides insight into trends in pollutant species in
the atmosphere. This study evaluates the spatial and
temporal trends in wet and dry deposition data from
the National Atmospheric Deposition Program/National
Trends Network (NADP/NTN) and the Clean Air Status
and Trends Network (CASTNET). Over the last twenty
years, most of the continental U.S. has experienced
statistically significant trends in one or more ion
species affecting acidic deposition. Some of these
trends appear directly attributable to changes in
regional emissions due to the 1990 Clean Air Act
Amendments. Other trends are influenced by the
equilibrium and reactions between atmospheric
species and other atmospheric processes. Long-term
trends in precipitation chemistry were found to
correlate with trends in gas and particulate
concentrations in the atmosphere for many species.
provides insight into trends in pollutant species in
the atmosphere. This study evaluates the spatial and
temporal trends in wet and dry deposition data from
the National Atmospheric Deposition Program/National
Trends Network (NADP/NTN) and the Clean Air Status
and Trends Network (CASTNET). Over the last twenty
years, most of the continental U.S. has experienced
statistically significant trends in one or more ion
species affecting acidic deposition. Some of these
trends appear directly attributable to changes in
regional emissions due to the 1990 Clean Air Act
Amendments. Other trends are influenced by the
equilibrium and reactions between atmospheric
species and other atmospheric processes. Long-term
trends in precipitation chemistry were found to
correlate with trends in gas and particulate
concentrations in the atmosphere for many species.