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External Quality-Assurance Project Report for the National Atmospheric Deposition Program National Trends Network and Mercury Deposition Network, 2021–22

Scientific Investigations Report 2024-5054
By: , , and 
https://doi.org/10.3133/sir20245054

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  • Document: Report (2.14 MB pdf) , HTML , XML
  • Data Releases:
    • USGS data release - Data for the U.S. Geological Survey Precipitation Chemistry Quality Assurance Project for the National Atmospheric Deposition Program, 1978–2017
    • USGS data release - U.S. Geological Survey Precipitation Chemistry Quality Assurance Project data 2017–2018
    • USGS data release - U.S. Geological Survey Precipitation Chemistry Quality Assurance Project data 2019–2020
    • USGS data release - U.S. Geological Survey Precipitation Chemistry Quality Assurance Project data 2021–2022
  • Download citation as: RIS | Dublin Core

Abstract

The U.S. Geological Survey Precipitation Chemistry Quality Assurance project (PCQA) operated five distinct programs to provide external quality-assurance monitoring for the National Atmospheric Deposition Program (NADP) National Trends Network (NTN) and Mercury Deposition Network (MDN) during 2021–22. The NTN programs included (1) a field audit program to evaluate sample contamination and stability, (2) an interlaboratory-comparison program to evaluate analytical laboratory performance, and (3) a colocated sampler program to estimate overall variability of NTN wet-deposition measurements, and the MDN programs included the (4) system blank program to evaluate sample contamination and stability and (5) an interlaboratory-comparison program. The results indicated increased levels of sample contamination compared to previous years for NTN samples and decreased contamination in MDN samples. Strong analytical laboratory performance with low overall variability and bias in concentration data was indicated for the NTN Central Analytical Laboratory. Slight perturbations in contamination levels in NTN samples and in analytical performance for MDN are considered inconsequential. The colocated sampler program results indicated overall variability in NTN data to range from 0 to 30.3 percent for cations, 1.6 to 11.4 percent for ammonium, 0.8 to 20.2 percent for anions, 10.3 to 17.2 percent for hydrogen-ion concentration, and 1.5 to 12.2 percent for specific conductance. The PCQA results indicate that NADP data continue to be of sufficient quality for applications in independent research and NADP data products, including spatial interpolations and time trends for chemical constituents in wet deposition. Small shifts in data quality indicated by the 2021–22 PCQA results are included to be used for interpretation of the NADP data products.

Suggested Citation

Deyette, N.A., Wetherbee, G.A., and Martin, R., 2024, External quality-assurance project report for the National Atmospheric Deposition Program National Trends Network and Mercury Deposition Network, 2021–22: U.S. Geological Survey Scientific Investigations Report 2024–5054, 34 p., https://doi.org/10.3133/sir20245054.

ISSN: 2328-0328 (online)

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Statistical Methods
  • Mercury Deposition Network Quality-Assurance Programs
  • Data Quality Assessment
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title External quality-assurance project report for the National Atmospheric Deposition Program National Trends Network and Mercury Deposition Network, 2021–22
Series title Scientific Investigations Report
Series number 2024-5054
DOI 10.3133/sir20245054
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) WMA - Observing Systems Division
Description Report: viii, 34 p.; 4 Data Releases
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details