aqStats.Rd
Calculate a range of air pollutionrelevant statistics by year.
aqStats(mydata, pollutant = "no2", type = "default", data.thresh = 0, percentile = c(95, 99), transpose = FALSE, ...)
mydata  A data frame containing a 

pollutant  The name of a pollutant e.g. 
type 

data.thresh  The data capture threshold in
if data capture over the period of interest is less than this value.

percentile  Percentile values to calculate for each pollutant. 
transpose  The default is to return a data frame with columns
representing the statistics. If 
...  Other arguments, currently unused. 
This function calculates a range of common and air pollutionspecific
statistics from a data frame. The statistics are calculated on an annual
basis and the input is assumed to be hourly data. The function can cope with
several sites and years e.g. using type = "site"
. The user can control the output by setting
transpose
appropriately.
Note that the input data is assumed to be in mass units e.g. ug/m3 for all species except CO (mg/m3).
The following statistics are calculated:
data.capture  percentage data capture over a full year.
mean  annual mean.
minimum  minimum hourly value.
maximum  maximum hourly value.
median  median value.
max.daily  maximum daily mean.
max.rolling.8  maximum 8hour rolling mean.
max.rolling.24  maximum 24hour rolling mean.
percentile.95  95th percentile. Note that several percentiles can be calculated.
roll.8.O3.gt.100  number of days when the daily maximum rolling 8hour mean ozone concentration is >100 ug/m3. This is the target value.
roll.8.O3.gt.120  number of days when the daily maximum rolling 8hour mean ozone concentration is >120 ug/m3. This is the Limit Value not to be exceeded > 10 days a year.
AOT40  is the accumulated amount of ozone over the threshold
value of 40 ppb for daylight hours in the growing season (April to
September). Note that latitude
and longitude
can also be
passed to this calculation.
hours.gt.200  number of hours NO2 is more than 200 ug/m3.
days.gt.50  number of days PM10 is more than 50 ug/m3.
For the rolling means, the user can supply the option align
, which
can be "centre" (default), "left" or "right". See rollingMean
for
more details.
There can be small discrepancies with the AURN due to the treatment of
rounding data. The aqStats
function does not round, whereas AURN data
can be rounded at several stages during the calculations.
## Statistics for 2004. NOTE! these data are in ppb/ppm so the ## example is for illustrative purposes only aqStats(selectByDate(mydata, year = 2004), pollutant = "no2")#> # A tibble: 1 x 15 #> # Groups: default, pollutant, year [1] #> default pollutant year date dat.cap mean min max median #> <fct> <chr> <dbl> <dttm> <dbl> <dbl> <int> <int> <dbl> #> 1 01 Jan~ no2 2004 20040101 00:00:00 99.8 55.0 0 185 51 #> # ... with 6 more variables: max_daily <dbl>, roll_8_max <dbl>, #> # roll_24_max <dbl>, percentile.95 <dbl>, percentile.99 <dbl>, hours <int>