National Trends Network

Project Description
National Trends Network (NTN): NTN is a 200-site network
located in rural sites where rain and snow are collected
weekly. Precipitation samples are analyzed by the Central
Analytical Laboratory (CAL) at the Illinois State Water Survey
for constituents, including nitrate, sulfate, pH, and other
major ions. Field and lab quality assurance programs are
included in the cost of the network to insure good quality data
that are comparable among sites. Data are presented in both
tabular and graphical format on the web and in special
publications within ninety days in draft form. Sponsors
include federal and state agencies, universities, public
utilities and industry groups.

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[Summary provided by NPS]