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

    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
AIRVOLAIRVOL

Total volume of air sampled, m3; value is calculated from exposure time and derived flow rate following the SOP; missing values are indicated by -9.0

Measurement type: Ratio
Units:
CHNGDATECHNGDATE

Most recent date and time any data values were edited within the NADPID set

Measurement type: DateTime
Date/Time Format: M-DD-YYYY hh:mm:ss
CONCCONC

Arithmetic average gaseous ammonia concentration, μg/m³; value is indicated as -9.00 if there were no valid individual replicate values during the sampling period

Measurement type: Ratio
Units:
ENDDATEENDDATE

End date and time of sample exposure, GMT

Measurement type: DateTime
Date/Time Format: M-DD-YYYY hh:mm:ss
NADPIDNADPID

Unique NADP identifier of individual sample sets consisting of one or more sample replicates and a travel blank deployed together

Measurement type: Nominal
QRQR

Quality Rating Code: A fully qualified with no problems, B valid data with minor problems, C invalid data

Measurement type: Nominal
SITEIDSITEID

Two-letter location designator followed by a two digit number

Measurement type: Nominal
STARTDATESTARTDATE

Start date and time of sample exposure, GMT

Measurement type: DateTime
Date/Time Format: M-DD-YYYY hh:mm:ss

Sampling Equipment

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

Current Equipment

  • Ammonia sampler
    Started: 2012-11-20

    One or more Radiello-brand diffusion-type passive samplers are attached to a plastic shelter mounted on a pole two meters above any surfaces.

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.