Description Usage Arguments Details Author(s) Examples
Calculate a range of air pollution-relevant statistics by year and by site.
1 2 |
mydata |
A data frame containing a |
pollutant |
The name of a pollutant e.g. |
data.thresh |
The data capture threshold in
calculated 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 pollution-specific
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. 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 8-hour rolling mean.
max.rolling.24 — maximum 24-hour 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 8-hour 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 8-hour 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.
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.
David Carslaw
1 2 3 | ## 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")
|
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.