aqs_sampledata_by_cbsa: aqs_sampledata_by_cbsa

In USEPA/RAQSAPI: A Simple Interface to the US EPA Air Quality System Data Mart API

aqs_sampledata_by_cbsa

Description

\lifecycle

stable Returns sample data where the data is aggregated at the Core Based Statistical Area (cbsa) level. If return_header is FALSE (default) this function returns a single dataframe with the requested data. If return_header is TRUE returns a list of AQSAPI_v2 objects where each index of the list is an individual RAQSAPI_v2 object returned from each successive call to the AQS API. RAQSAPI_v2 objects are two item list where the $Data portion contains data that contains sample air monitoring data at a site with the input parameter and cbsa_code provided for bdate - edate time frame. The $Header is a tibble of header information from the API call /(useful for debugging/). This function returns NULL is bdate > edate.

Usage

aqs_sampledata_by_cbsa(
  parameter,
  bdate,
  edate,
  cbsa_code,
  duration = NA_character_,
  cbdate = NA_Date_,
  cedate = NA_Date_,
  return_header = FALSE
)

Arguments

parameter	a character list or a single character string which represents the parameter code of the air pollutant related to the data being requested.
bdate	a R date object which represents that begin date of the data selection. Only data on or after this date will be returned.
edate	a R date object which represents that end date of the data selection. Only data on or before this date will be returned.
cbsa_code	a R character object which represents the 5 digit AQS Core Based Statistical Area code (the same as the census code, with leading zeros)
duration	an optional R character string that represents the parameter duration code that limits returned data to a specific sample duration. The default value of NA_character_ results in no filtering based on duration code.Valid durations include actual sample durations and not calculated durations such as 8 hour CO or $O_3$ rolling averages, 3/6 day PM averages or Pb 3 month rolling averages. @seealso aqs_sampledurations() for a list of all available duration codes.
cbdate	a R date object which represents a "beginning date of last change" that indicates when the data was last updated. cbdate is used to filter data based on the change date. Only data that changed on or after this date will be returned. This is an optional variable which defaults to NA_Date_.
cedate	a R date object which represents an "end date of last change" that indicates when the data was last updated. cedate is used to filter data based on the change date. Only data that changed on or before this date will be returned. This is an optional variable which defaults to NA_Date_.
return_header	If FALSE (default) only returns data requested. If TRUE returns a AQSAPI_v2 object which is a two item list that contains header information returned from the API server mostly used for debugging purposes in addition to the data requested.

Value

a tibble or an AQS_Data_Mart_APIv2 S3 object containing sample data for all monitors matching cbsa_code for the given parameter. An AQS_Data Mart_APIv2 is a 2 item named list in which the first item /(/$Header/) is a tibble of header information from the AQS API and the second item /(/$Data/) is a tibble of the data returned.

Note

The AQS API only allows for a single year of sampledata to be retrieved at a time. This function conveniently extracts date information from the bdate and edate parameters then makes repeated calls to the AQSAPI retrieving a maximum of one calendar year of data at a time. Each calendar year of data requires a separate API call so multiple years of data will require multiple API calls. As the number of years of data being requested increases so does the length of time that it will take to retrieve results. There is also a 5 second wait time inserted between successive API calls to prevent overloading the API server. Fortunately this operation has a linear run time /(Big O notation: O/(n + 5 seconds/)/)

See Also

Other Aggregate _by_cbsa functions: aqs_annualsummary_by_cbsa(), aqs_dailysummary_by_cbsa(), aqs_monitors_by_cbsa()

Examples

# returns tibble which contains $NO_{2}$ data
          #  for Charlotte-Concord-Gastonia, NC cbsa for
          #  Janurary 1, 2015 - Janurary 01, 2017
          ## Not run: aqs_sampledata_by_cbsa(parameter = "42602",
                                          bdate = as.Date("20150101",
                                                          format = "%Y%m%d"),
                                          edate = as.Date("20170101",
                                                          format = "%Y%m%d"),
                                          cbsa_code = "16740"
                                         )
                   
## End(Not run)

USEPA/RAQSAPI documentation built on Jan. 18, 2024, 1:50 a.m.