I have been monitoring the air polution since Yokohama city started its measurement in 2012 (one year after the nuclear plant incident).
Yokohama, where I live, is located almost 155 miles away from the exploded Fukushima nuclear plant.
While Yokohama did not have such direct impact from the explosion, poluted air came over the city.
Yokohama city, responding to the voices from the citizens, relutacntly startes its own measurement of the radioactivity density in the air and has been announcing evey hour.
I have been updating a chart every two weeks using an average of the period.
Here, “average” really works as it compresses 336 hourly data (24 hour x 14 days) into one average, which is really suitable for the trend chart. (vertical axis shows nGy/h)
Now, after the three years, it is closing to the original range before the incident.
This is one of the good example using “average” effectively.