EMS Math-Science Cross-Curricular Lessons 2

Question 1

An EMS auditor calculates that a facility emits 450 kg of NOx per month. If the regulatory limit is 5,000 kg per year, what percentage of the annual limit is the facility using monthly?

Accepted Answer

9%

Answer

450 kg ÷ (5,000 kg ÷ 12 months) = 450 ÷ 416.7 ≈ 108%; 450 ÷ 5,000 = 9% of the annual limit.

Question 2

Which scientific principle explains why dissolved oxygen (DO) levels in a receiving water body decrease after an industrial facility discharges warm effluent?

Accepted Answer

Henry's Law — gas solubility decreases as temperature increases

Answer

Henry's Law states that gas solubility in liquids decreases with increasing temperature, reducing DO when warm effluent is discharged.

Question 3

A facility tracks VOC emissions quarterly (in tonnes): Q1=12, Q2=15, Q3=18, Q4=11. What is the standard deviation closest to?

Accepted Answer

2.9

Answer

Mean=14; deviations squared: 4, 1, 16, 9; variance=7.5; SD=√7.5≈2.74, closest to 2.9 among the options.

Question 4

During an EMS audit, an auditor notes pH readings of 6.2, 6.5, 6.8, and 7.1 in a treatment pond over four days. What does an upward pH trend most likely indicate in a biological treatment system?

Accepted Answer

Increasing microbial activity consuming CO₂

Answer

Aerobic microbial metabolism consumes CO₂, raising pH, so an upward trend indicates increasing biological activity.

Question 5

A company reduces energy consumption from 10,000 GJ to 8,500 GJ per year. Using an emission factor of 56 kg CO₂/GJ, what is the annual CO₂ reduction in metric tonnes?

Accepted Answer

84 t CO₂

Answer

Reduction = 1,500 GJ × 56 kg CO₂/GJ = 84,000 kg = 84 metric tonnes CO₂.

(EMS) Environmental Management Systems Internal Auditor Certification Practice Test

(EMS) Environmental Management Systems Internal Auditor Certification Practice Test

EMS Math-Science Cross-Curricular Lessons 2