Concentrations will decrease to one-quarter of their initial value.
Explanation:
The relative effects of the changes in the velocity of the wind on the pollutant concentration will decrease in one-quarter of the initial values.
When assuming the pollutant concentration is negligible upwind to the content downwards.
The concentration will be the emission rate gets reduced to the one-quarter of the initial value and then by the pollution concentration will be reduced with downwind.
