AQS Assessment & Monitoring Methods 4

Question 1

Which EPA Method is used to determine the concentration of hydrogen chloride (HCl) and chlorine gas (Cl2) in stationary source emissions?

Accepted Answer

Method 26A

Answer

EPA Method 26A is the reference method for measuring HCl and Cl2 in stack gases using isokinetic sampling and ion chromatography.

Question 2

A monitoring data gap occurs when a SLAMS PM2.5 FRM sampler misses scheduled collection. Under 40 CFR Part 50, Appendix N, how many valid 24-hour samples are required per quarter for NAAQS comparison?

Accepted Answer

At least 11 valid samples per quarter

Answer

Appendix N requires a minimum of 11 valid 24-hour PM2.5 samples per quarter for the data to be used in NAAQS comparisons.

Question 3

In a source apportionment study using the Chemical Mass Balance (CMB) model, which input is required for each source category?

Accepted Answer

Source profile — the fractional abundance of each species in that source's emissions

Answer

CMB requires a chemical source profile (the species composition of each source's emissions) to solve the mass balance equation at the receptor.

Question 4

Sonic anemometers used in flux measurement programs calculate turbulent fluxes via eddy covariance. What critical correction must be applied to account for sensor separation and air density fluctuations?

Accepted Answer

Webb-Pearman-Leuning (WPL) density correction and time-lag cross-correlation

Answer

The WPL correction accounts for air density fluctuations due to heat and water vapor, while cross-correlation corrects for physical separation between sensors.

Question 5

An industrial hygienist collects a personal air sample using a charcoal tube for VOC analysis. If the breakthrough volume is exceeded during sampling, what error occurs?

Accepted Answer

Negative bias — analytes escape through the backup section, under-reporting exposure

Answer

When breakthrough occurs, analytes pass through the backup charcoal section and are lost, causing under-reporting of actual concentrations.

(AQS) Air Quality Specialist Certification Practice Test

(AQS) Air Quality Specialist Certification Practice Test

AQS Assessment & Monitoring Methods 4