The Air Quality Index (AQI) is used for reporting on air quality in the United States, and focuses on short term health effects as a result of breathing polluted air.
The AQI is calculated separately for 5 pollutants: ozone (O3), particulate matter (PM2.5 and PM10), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2) based on maximum values (of various averaging periods) for a particular day. The highest AQI value among each pollutants value for that day is recorded as the AQI and the corresponding pollutant is reported as the principal pollutant.
The US EPA has established risk categories and associated health messaging for AQI ranges including: "Good" (0-50), "Moderate" (51-100), "Unhealthy for Sensitive Groups" (101-150), "Unhealthy" (151-200), "Very Unhealthy" (200-300), and "Hazardous" (301-500). AQI values above 500 are considered "Beyond the AQI", but AQI values will still be calculated for relative comparisons.
Usage
AQI(
dates = Sys.time(),
o3_8hr_ppm = NA,
o3_1hr_ppm = NA,
pm25_24hr_ugm3 = NA,
pm25_1hr_ugm3 = NA,
pm10_24hr_ugm3 = NA,
pm10_1hr_ugm3 = NA,
co_8hr_ppm = NA,
co_1hr_ppm = NA,
so2_1hr_ppb = NA,
no2_1hr_ppb = NA
)Arguments
- dates
Vector of hourly dates corresponding to observations. Date gaps will be filled automatically.
- o3_8hr_ppm
(Optional) Numeric vector of hourly 8-hour mean ozone (O3) concentrations (ppm). Will be calculated from o3_1hr_ppm if provided and o3_8hr_ppm not provided.
- o3_1hr_ppm
(Optional) Numeric vector of hourly 1-hour mean ozone (O3) concentrations (ppm).
- pm25_24hr_ugm3
(Optional) Numeric vector of hourly 24-hour mean fine particulate matter (PM2.5) concentrations (ug/m^3). Will be calculated from pm25_1hr_ugm3 if provided and pm25_24hr_ugm3 not provided.
- pm25_1hr_ugm3
(Optional) Numeric vector of hourly 1-hour mean fine particulate matter (PM2.5) concentrations (ug/m^3).
- pm10_24hr_ugm3
(Optional) Numeric vector of hourly 24-hour mean coarse particulate matter (PM10) concentrations (ug/m^3). Will be calculated from pm10_1hr_ugm3 if provided and pm10_24hr_ugm3 not provided.
- pm10_1hr_ugm3
(Optional) Numeric vector of hourly 1-hour mean coarse particulate matter (PM10) concentrations (ug/m^3).
- co_8hr_ppm
(Optional) Numeric vector of hourly 8-hour mean carbon monoxide (CO) concentrations (ppm). Will be calculated from co_1hr_ppm if provided and co_8hr_ppm not provided.
- co_1hr_ppm
(Optional) Numeric vector of hourly 1-hour mean carbon monoxide (CO) concentrations (ppm).
- so2_1hr_ppb
(Optional) Numeric vector of hourly 1-hour mean sulfur dioxide (SO2) concentrations (ppb). 24-hour averages will be calculated automatically.
- no2_1hr_ppb
(Optional) Numeric vector of hourly 1-hour mean nitrogen dioxide (NO2) concentrations (ppb).
Value
A tibble (data.frame) with columns: date, AQI, risk_category, principal_pol and 1 row for each day between the min and max values of the provided dates
See also
Other Air Quality Standards:
CAAQS()
Examples
AQI(o3_8hr_ppm = 0.078, o3_1hr_ppm = 0.104, pm25_24hr_ugm3 = 35.9)
#> # A tibble: 1 × 4
#> date AQI risk_category principal_pol
#> <dttm> <dbl> <fct> <fct>
#> 1 2025-11-18 00:00:00 126 Unhealthy for Sensitive Groups o3
AQI(o3_1hr_ppm = 0.104, pm25_24hr_ugm3 = 35.9)
#> # A tibble: 1 × 4
#> date AQI risk_category principal_pol
#> <dttm> <dbl> <fct> <fct>
#> 1 2025-11-18 00:00:00 102 Unhealthy for Sensitive Groups pm25