Get the EPA monitoring day from a date

Returns the corresponding day in the EPA's 12-day sampling schedule for the given date.

epa_schedule(d)

Arguments

d

A date.

Value

An integer from 1 to 12 representing the day in the EPA's 12-day monitoring schedule.

Details

The EPA collects some samples every 3, 6, or 12 days. It provides a recurring 12-day schedule for these samples. This function represents the schedule with the integers 1 to 12. A sample taken every 3 days should be collected on days 3, 6, 9, and 12. A sample on the 6-day schedule should be collected on days 6 and 12, and a sample on the 12-day schedule should be collected on day 12.

See also

https://www.epa.gov/amtic/sampling-schedule-calendar, https://www3.epa.gov/ttn/amtic/calendar.html

Examples

epa_schedule(as.Date('2020-01-01'))
#> [1] 9