get_station_imeca: Download pollution data by station in IMECAs

Description

Retrieve hourly averages of pollution data, by station, measured in IMECAs

Usage

get_station_imeca(pollutant, date, show_messages = TRUE)

Value

A data.frame with pollution data measured in IMECAs, by station. The hours correspond to the Etc/GMT+6 timezone, with no daylight saving time

Arguments

pollutant

The type of pollutant to download

SO2 - Sulfur Dioxide
CO - Carbon Monoxide
NO2 - Nitrogen Dioxide
O3 - Ozone
PM10 - Particulate matter 10 micrometers or less
PM25 - Particulate matter 2.5 micrometers or less

date

The date for which to download data in YYYY-MM-DD format (the earliest possible date is 2009-01-01).

show_messages

show a message about issues with excluded stations

Details

Note that in 2015 it was determined that the stations with codes ACO, AJU, INN, MON and MPA would no longer be taken into consideration when computing the pollution index because they didn't meet the objectives of monitoring air quality, and are no longer included in the index, even if they are still part of the SIMAT (Sistema de Monitoreo Atmosférico de la Ciudad de México). Thus, even if they are located inside a zone, they are not included in the pollution values for that zone.

Examples

Run this code

if (FALSE) {
## There was an ozone pollution emergency on May 15, 2017
df_o3 <- get_station_imeca("O3", "2017-05-15", show_messages = FALSE)

## Convert to local Mexico City time
df_o3$mxc_time <- format(as.POSIXct(paste0(df_o3$date,
                                           " ",
                                           df_o3$hour,
                                           ":00"),
                                    tz = "Etc/GMT+6"),
                         tz = "America/Mexico_City")
head(df_o3[order(-df_o3$value), ])
}