Question

introduction to sustainability quiz
questions 1 through 3 refer to the following.
summary of mean water quality results
green roof
mean
control roof
mean
precipitation
mean
ph
7.28
6.27
4.82
nitrate (mg/l)
0.27
0.87
0.6
ammonium (mg/l)
0.86
1.47
1.19
total phosphorus
(mg/l)
0.47
0.25
0.21
magnesium (mg/l)
2.92
0.25
0.20
boron (mg/l)
0.58
0.03
0.00
green roofs offer many environmental advantages, including the removal of some pollutants from
rainwater. the parameters in the table above were measured in water samples collected after rainfall had
passed through green roofs and over traditional roofs (n = 5) in new york city. mean levels of ph and
pollutants in precipitation are shown in the table.
2
mark for review
the data in the table show mean concentrations (mg/l) of pollutants in rainwater leaving either green or
conventional roofs. which of the following data would be needed to calculate the total amount of a
pollutant leaving the roof during and following a rainstorm?
a distance from street level to roof
b duration of the rain event
c total number of plants on the roof
d total volume of rainfall

Explanation:

To calculate the total amount of a pollutant leaving the roof, we use the formula \( \text{Total amount}=\text{Concentration (mg/L)}\times\text{Volume (L)} \). The concentration of pollutants is given in \( \text{mg/L} \). So, we need the total volume of rainfall (in liters) to complete the calculation.

• Option A: Distance from street level to roof is not relevant for calculating pollutant amount.
• Option B: Duration of the rain event does not directly give the volume of water (and thus is not sufficient for calculating pollutant amount).
• Option C: Total number of plants on the roof is not related to the formula for calculating pollutant amount (\( \text{Concentration}\times\text{Volume} \)).
• Option D: Total volume of rainfall is necessary as \( \text{Total amount of pollutant}=\text{Pollutant concentration (mg/L)}\times\text{Rainfall volume (L)} \).

Answer:

D. Total volume of rainfall