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| | NPS: Nature & Science» Air Resources Division-Monitoring (Site not responding. Last check: 2007-10-31) |
 | | Dry deposition of particles and gases occurs by complex processes such as settling, impaction, and adsorption. |
 | | The NADP National Trends Network (NTN) collects weekly precipitation samples that are analyzed by a central analytical laboratory at the Illinois State Water Survey for pH, conductivity, cations (hydrogen, calcium, sodium, magnesium, potassium, and ammonium) and anions (sulfate, nitrate, and chloride). |
 | | Data for both networks is available on the NADP web site. |
| www2.nature.nps.gov /air/monitoring/wetmon.cfm (475 words) |
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