The rain in the plains is mainly very clean, according to an 18-year, nationwide program monitoring chemical content of precipitation.
IANR Agricultural Meteorologist Shashi Verma pushed for Nebraska to be one of 20 original monitoring sites in the National Atmospheric Deposition Program/National Trends Network when it began in 1978. The program, a cooperative effort of local, state and federal agencies, originated in response to concerns about acid rain.
Verma thought a Nebraska site would have particular value because Nebraska's air, moving in from the west, is scrubbed clean of acid rain particles in its trip over the Rocky Mountains.
Verma was right, said Mark Mesarch, agricultural meteorology research technologist.
"Our air is so free of acid rain constituents like sulfates and nitrates that readings from the Nebraska site have been used as the baseline for trend studies over the last 10 to 15 years," Mesarch said.
Every Tuesday morning an IANR employee collects a precipitation sample at NU's Agricultural Research and Development Center near Ithaca. Other people make collections at 200 monitoring sites across the nation.
Samples are tested for pH and conductance, then sent to an Illinois laboratory where they're extensively analyzed for nitrogen components, sulfates, chlorine, potassium, manganese and other chemical contents.
Clean air legislation passed by Congress in 1990 and 1995 aims to reduce industrial emissions that release these chemicals into the air, Mesarch said. The National Atmospheric Deposition Program helps determine if restrictions have an effect.
--Monica Manton Norby