Details and Metadata

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Methods

The methods followed in the creation of the dataset, including description of field, laboratory and processing steps, and quality control procedures

Current Methods

  • Ammonia and ammonium collection
    Started: 2012-11-20

    Passive diffusion-type samplers are deployed for two week periods year-round. Each sampler accumulates ammonia and ammonium for the period then is collected and shipped to a central laboratory for analysis using sonification and flow injection analysis.

  • Atmospheric pollutants and meteorological dat
    Started: 2012-11-20

    Each CASTNET site measures atmospheric sulfur and nitrogen pollutants and cations. Concentrations of ambient sulfur and nitrogen species are collected and measured weekly (Tuesday to Tuesday, 168 hours) via a three-stage filter pack, and the data are averaged over the 1-week period.

Dataset Fields

Detailed documentation of the fields comprising the dataset, including the type of measurement, units where applicable, and any controlled vocabularies or code lists present in the data


Field Name Caption Description Additional Information
SITE_IDSite ID

Site identification code

Measurement type: Nominal
YEARYear

Calendar year of measurement using standard Tuesday to Tuesday weeks

Measurement type: DateTime
Date/Time Format: YYYY
WEEKWeek

Week of year as defined by the first Tuesday to Tuesday week of the year

Measurement type: Ratio
Unit: unavailable
Precision: 1
DATEONDate On

Date and time standard Tuesday to Tuesday period began Local Standard Time

Measurement type: DateTime
Date/Time Format: YYYY-MM-DDThh:mm:ss
DATEOFFDate Off

Date and time standard Tuesday to Tuesday period ended Local Standard Time

Measurement type: DateTime
Date/Time Format: YYYY-MM-DDThh:mm:ss
SO2_CONCSO2 Concentration

Mean ambient sulfur dioxide (SO2) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
SO4_CONCSO4 Concentration

Mean ambient particulate sulfate (SO4) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
NO3_CONCNO3 Concentration

Mean ambient particulate nitrate (NO3) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
HNO3_CONCHNO3 Concentration

Mean ambient nitric acid (HNO3) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
TNO3_CONCTNO3 Concentration

Total ambient nitrate (NO3+HNO3) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
NH4_CONCNH4 Concentration

Mean ambient particulate ammonium (NH4) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
CA_CONCCa Concentration

Mean ambient particulate calcium (Ca) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
NA_CONCNa Concentration

Mean ambient particulate sodium (Na) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
MG_CONCMg Concentration

Mean ambient particulate magnesium (Mg) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
K_CONCK Concentration

Mean ambient particulate potassium (K) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001
CL_CONCCl Concentration

Mean ambient particulate chloride (Cl) concentration

Measurement type: Ratio
Unit: unavailable
Precision: 0.001

Sampling Equipment

Equipment and software used to collect data, including how that equipment was used.

Current Equipment

  • Filter pack
    Started: 2012-12-20

    A CASTNET filter pack and vacuum pump pulls 3 liters per minute ambient air through different filters

Site Characteristics

The spatial extent of the dataset site coverage, and descriptions of the spatial extent and context for the data collection

  • Site Description

    Mount Mansfield site located at 400 m elevation on the west slope in the field station at Proctor Maple Research Center. Consistent with National Atmospheric Deposition Program/AMoN Siting Criteria

  • Site Description

    As of October 2011, eighty two CASTNET sites were operational at eighty distinct locations. Most CASTNET sites are located in rural or remote locations away from pollutant emission sources and heavily populated areas

  • Site Description

    The network design of CASTNET involves the measurement of rural, regionally representative concentrations of sulfur and nitrogen species to estimate dry deposition fluxes and to assess trends over time and space. Eastern U.S. sites are selected based on the following factors: (1) regional representation (2) distance from major pollutant sources (3) long-term availability, (4) accessibility, and (5) contribution to overall geographic coverage.

  • Site Description

    For the western CASTNET sites, the limited number of sites and higher diversity of the region make it difficult to follow spatial patterns. Therefore, site selection in the west focuses primarily on locations where specific research issues can be addressed, and where natural resources are at risk.