A pre-generated pa_synoptic object will be loaded for
the given date. These files are generated each day and provide
a record of all currently installed PurpleAir sensors for the day of
interest. With default arguments, this function will always load data
associated with the most recent pre-generated file -- typically less than
one hour old.
The datestamp
can be anything that is understood by
lubrdiate::ymd()
including either of the following recommended
formats:
By default, the host computer's date is used.
The pas object for a specific hour may be loaded by specifying
datestamp = "YYYYmmddHH"
.