AQS Assessment & Monitoring Methods 5

Question 1

In mobile air monitoring using a vehicle-mounted sensor array, what is the primary purpose of co-location with a reference monitor before deployment?

Accepted Answer

To derive transfer functions that correct mobile sensor readings to reference-equivalent concentrations

Answer

Co-location generates correction equations (transfer functions) that account for sensor-specific biases, improving data comparability to regulatory reference methods.

Question 2

Under NIOSH Method 7500, which technique is used to identify and quantify crystalline silica in workplace air samples?

Accepted Answer

X-ray powder diffraction (XRD)

Answer

NIOSH 7500 uses XRD to identify crystalline silica polymorphs (quartz, cristobalite) because each polymorph produces a unique diffraction pattern.

Question 3

A dispersion model predicts a 24-hour PM2.5 concentration of 38 µg/m³ at a receptor. The current 24-hour NAAQS is 35 µg/m³. What is the next required regulatory action for a major source permit applicant?

Accepted Answer

Demonstrate that the modeled concentration, with background added, remains below the NAAQS through emission reductions or design changes

Answer

If modeling plus background exceeds the NAAQS, the applicant must redesign the project or add controls to reduce emissions until modeled concentrations comply.

Question 4

Which parameter does a rotating shadowband radiometer (RSR) specifically measure that is critical for photochemical air quality modeling?

Accepted Answer

Direct normal and diffuse solar irradiance to calculate photolysis rates

Answer

RSRs measure direct and diffuse solar radiation components, which are inputs used to calculate photolysis rate constants (J-values) in photochemical models.

Question 5

What is the key advantage of using a Low-Volume sampler (Lo-Vol) over a Hi-Vol sampler for PM2.5 collection in remote areas with limited power?

Accepted Answer

Lo-Vol samplers consume less power (~10 W) and maintain accurate flow control at lower flow rates (~16.7 L/min)

Answer

Lo-Vol samplers operate at ~16.7 L/min with much lower power consumption than Hi-Vol units, making them suitable for solar or battery-powered remote deployments.

(AQS) Air Quality Specialist Certification Practice Test

(AQS) Air Quality Specialist Certification Practice Test

AQS Assessment & Monitoring Methods 5