QA101: 40 CFR 58 App. A - Gaseous Pollutants Glenn Gehring, Technology Specialist III Institute for Tribal Environmental Professionals glenn.gehring@nau.edu Voice: 541-612-0899 http://www4.nau.edu/itep/ http://www4.nau.edu/tams/

40CFR Part 58 Appendix A The Code of Federal Regulations (CFRs) are dynamic; always check to be sure you have the latest information.

CFR Title 40 Part 58 Appendix A 3.2.1  One-Point Quality Control Check for SO2, NO2, O3, and CO. A one-point quality control (QC) check must be performed at least once every 2 weeks on each automated analyzer used to measure SO2, NO2, O3and CO.  … The QC check is made by challenging the analyzer with a QC check gas of known concentration (effective concentration for open path analyzers) between 0.01 and 0.10 parts per million (ppm) for SO2, NO2, and O3, and between 1 and 10 ppm for CO analyzers. 3.2.1.1  Except for certain CO analyzers described below, point analyzers must operate in their normal sampling mode during the QC check, and the test atmosphere must pass through all filters, scrubbers, conditioners and other components used during normal ambient sampling and as much of the ambient air inlet system as is practicable. … 3.2.1.3  Report the audit concentration … of the QC gas and the corresponding measured concentration … indicated by the analyzer. The percent differences between these concentrations are used to assess the precision and bias of the monitoring data as described in sections 4.1.2 (precision) and 4.1.3 (bias) of this appendix.

Inside the Monitoring Shelter Vertical manifold Tubing for NOy Gas Analyzer Rack Toxics Flow Controller 316 Stainless Steel 1/8 inch tubing connects regulator to calibrator NOy Data Logger Continuous Particulate Sensor Unit NOx Calibrator SO2 Continuous Particulate Monitor Control Units Ozone CGA 660? Fitting must match bottle Zero Air Generator EPA Protocol Gas

(2 stage stainless steel match fittings & purge CGA 660) Calibration System Pneumatics Don’t pressurize analyzers; you must vent. Total flow from calibrator must exceed combined analyzer demand Wall Zero Air Calibration Manifold – may have one on calibrator Vent Calibrator Regulator (2 stage stainless steel match fittings & purge CGA 660) Cal gas must pass through filter Cal Bottle Analyzer Analyzer Analyzer EPA Protocol Gas Most have 2-year certification Exhaust manifold Insect screen

What is Zero Air? From QA-Handbook – Vol – II (Redbook): Zero Air Systems: Zero air systems should be able to deliver 10 liters/min of air that is free of ozone, NO, NO2, and SO2 to 0.001 ppm and CO and non-methane hydrocarbons to 0.1 ppm. There are many commercially available systems; however, simple designs can be obtained by using a series of canisters. From 40CFR Part 50 Appendix A-1 (this is not Part 58, Appendix A) SO2 4.1.6.2 Clean zero air, free of contaminants that could cause a detectable response or a change in sensitivity of the analyzer. Since ultraviolet fluorescence analyzers may be sensitive to aromatic hydrocarbons and O2-to-N2ratios, it is important that the clean zero air contains less than 0.1 ppm aromatic hydrocarbons and O2and N2percentages approximately the same as in ambient air. A procedure for generating zero air is given in reference 1.

What is Zero Air? (continued) From 40CFR Part 50 Appendix C (this is not Part 58, Appendix A) CO 3.2 Dilution gas (zero air). Air, free of contaminants which will cause a detectable response on the CO analyzer. The zero air should contain <0.1 ppm CO. A procedure for generating zero air is given in Reference 1. From 40CFR Part 50 Appendix F (this is not Part 58, Appendix A) NOx 1.3.2 Zero air. Air, free of contaminants which will cause a detectable response on the NO/NOX/NO2analyzer or which might react with either NO, O3, or NO2in the gas phase titration. A procedure for generating zero air is given in reference 13.

Commercial Zero Air Generator Series of scrubbers Desiccant, Purafil, Molecular sieve, activated carbon, whatever scrubber media is needed (supply a clean, cooled, dry air flow source that meets pressure needs – always put a 0.1 micron particulate filter downstream of scrubbers)

From QA-Handbook – Vol – II (Redbook): What are Gas Standards? From QA-Handbook – Vol – II (Redbook): 12.1.2 Gaseous Standards In general, ambient monitoring instruments should be calibrated by allowing the instrument to sample and analyze test atmospheres of known concentrations of the appropriate pollutant in air. The following is an excerpt from 50 CFR Part 58, Appendix A Section 2.6.1: “Gaseous pollutant concentration standards (permeation devices or cylinders of compressed gas) used to obtain test concentrations for carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxide (NO), and nitrogen dioxide (NO2) must be traceable to either a National Institute of Standards and Technology (NIST) Traceable Reference Material (NTRM) or a NIST-certified Gas Manufacturer’s Internal Standard (GMIS), certified in accordance with one of the procedures given in reference 4 of this appendix. Vendors advertising certification with the procedures provided in reference 4 of this appendix and distributing gasses as ‘‘EPA Protocol Gas’’ must participate in the EPA Protocol Gas Verification Program or not use ‘‘EPA’’ in any form of advertising.” "Traceable" is defined in 40 CFR Parts 50 and 58 as meaning that a local standard has been compared and certified, either directly or via not more than one intermediate standard, to a primary standard such as a National Institute of Standards and Technology Standard Reference Material (NIST SRM) or a USEPA/NIST-approved Certified Reference Material (CRM)”.

From 40CFR Part 50 Appendix A-1 (this is not Part 58, Appendix A) 4.1.6.1 SO2 gas concentration transfer standard having a certified SO2 concentration of not less than 10 ppm, in N2, traceable to a NIST Standard Reference Material (SRM). From 40CFR Part 50 Appendix C (this is not Part 58, Appendix A) 3.1 CO concentration standard(s). Cylinder(s) of CO in air containing appropriate concentrations(s) of CO suitable for the selected operating range of the analyzer under calibration; CO standards for the dilution method may be contained in a nitrogen matrix if the zero air dilution ratio is not less than 100:1. The assay of the cylinder(s) must be traceable either to a National Bureau of Standards (NBS) CO in air Standard Reference Material (SRM) or to an NBS/EPA-approved commercially available Certified Reference Material (CRM). CRM's are described in Reference 2, and a list of CRM sources is available from the address shown for Reference 2. A recommended protocol for certifying CO gas cylinders against either a CO SRM or a CRM is given in Reference 1. CO gas cylinders should be recertified on a regular basis as determined by the local quality control program.

From 40CFR Part 50 Appendix F (this is not Part 58, Appendix A) 1.3.1 NO concentration standard. Gas cylinder standard containing 50 to 100 ppm NO in N2with less than 1 ppm NO2. This standard must be traceable to a National Bureau of Standards (NBS) NO in N2Standard Reference Material (SRM 1683 or SRM 1684), an NBS NO2Standard Reference Material (SRM 1629), or an NBS/EPA-approved commercially available Certified Reference Material (CRM).  Basically, if you purchase EPA Protocol Gas at the right concentrations things should be good. BUT, there are factors and calculations that impact what concentration you can get out of your gas calibrator. Let’s talk more about generating a test gas atmosphere to better understand this.

Creating a Test Atmosphere

Basically, it’s mostly about mixing ratios. 15 parts this 2 parts this Test Atmosphere Zero Air Cal Gas Concentration & Flow Gas/Titration/ Ozone Flow Concentration & Flow Flow must be correct!

Environics 6100 gas calibrator with 100 ml/min Mass flow Controller (MFC) for the calibration gas and a 10 liter/min (10,000 ml/min) zero air flow. Flow controller limits – not trusted below 10% of range (10 ml/minute is the minimum allowable flow on the cal gas MFC – 8ml/min won’t work) These flow controllers are calibrated at EPA Standard flow (25˚C at 760 mmHg)

Note: most of the gas in a calibration bottle is actually N2 Note: most of the gas in a calibration bottle is actually N2. Gasses flow differently and calibrators sometimes ask what the source gas is in order to make small adjustments to flow. If the cal gas is 50 ppm NO and 50 ppm SO2, almost all the gas in the bottle is actually the mostly inert carrier gas, N2. In this case flow would be set for N2 and not SO2 or NO. The concentrations entered for concentration calculations would be NO and SO2. NO2 is typically generated by reacting ozone with the nitrogen oxide gas (NO) from a cal bottle in the calibrator. This is called Gas Phase Titration (GPT)

Step 1. How much total flow do I want? I need enough flow for each analyzer and some excess to ensure outside air won’t mix with my test atmosphere Analyzer 1 draws 0.5 slpm – Analyzer 2 draws 0.6 slpm - analyzer 3 draws 1.0 slpm 0.5 + 0.6 + 1.0 = a total analyzer draw of 2.1 slpm - add excess Let’s make total flow 3.1 slpm. 3.1 standard liters per minute is the same as 3100 standard cubic centimeters per minute (A rotameter in the vent line can assure excess flow – it will measure flow and you just look – tap the floating ball to be sure it isn’t stuck)

Step 2 – Calculate from this formula (Flow of cal gas) X [cal gas bottle concentration] [concentration of gas out ] = Flow of zero air + Flow of cal gas + other flows (note: the denominator adds up to total flow) What do we know? Say we want a cal gas out of .090 ppm; we can pick that and “concentration of gas out” is then known. We decided we wanted a total flow of 3.1 slpm (3100 sccm) so we know the total of the denominator, total flow. We also know the calibration gas concentration (you can read it from the cal bottle – let’s say it reads 50.1 ppm). What don’t we know? We need to know the flow of the cal gas. Think algebra and solve for flow of cal gas in the numerator in sccm units. WATCH your units! (Flow of cal gas) X (50.1 ppm) 0.090 ppm = 3100 sccm (0.090 ppm) X (3100 sccm) = (Flow of cal gas) = 5.569 sccm PROBLEM!!!!!!!! 50.1 ppm

We did the calculation right so what’s the problem? Our 100 ml/min calibration gas mass flow controller in the 6100 isn’t accurate below 10% of their flow maximum - 10% of 100 is 10 and we ended up with 5.569. We need to have a higher total flow, a smaller mass flow controller for the cal gas (a 50 sccm flow controller would work in this instance) or a lower concentration cal gas. The easiest might be to just increase total flow, but there are limits. It’s a balancing act between total flows, cal gas concentrations and the flow limits of your calibrator mass flow controllers. Let’s explore this further. Let’s find out what the minimum total flow would need to be in order to keep the cal gas flow at 10% of the 100 sccm mass flow controller. This time we’ll solve for total flow (Flow of cal gas is 10 sccm) X (50.1 ppm) 0.090 ppm = Total Flow (10 sccm) X (50.1 ppm) Total Flow = = 5567 sccm 0.090 ppm I can adjust my gas calibrator for a total flow of 5570 sccm instead of 3100 sccm and get .090 out; we will have additional flow to vent

What is the lowest concentration we can get from a 50 What is the lowest concentration we can get from a 50.1 ppm cal gas bottle concentration with 10 liter zero air mass flow controller and a 100 sccm cal gas mass flow controllers in a calibrator? Lets only use 100% at the top end of the zero air mass flow controller, or 10000 sccm (10 slpm) and the minimum flow of 10 sccm for the cal gas mass flow controller (10% of 100 sccm). (Flow of cal gas is 10 sccm) X (50.1 ppm) Output ppm = = .050 ppm 10010 for total flow

NOx Analyzer Theory of Operation: Chemiluminescence

Light leaks can impact measurement Sample gas w/NO O3 Light leaks can impact measurement PMTs are sensitive and can be damaged by light Illustration is from Teledyne API 200E Operator’s manual

Illustration is from Teledyne API 200E Operator’s manual

MolyCon Molybdenum Converter NOx Cycle goes through converter Dark Cycle bypasses RX Cell Only NO reacts with ozone MolyCon Molybdenum Converter NO2 Converter Sample Air NOx = NO + NO2 NOx – NO = NO2 NO NO Rx Cell PMT NOx NO2 NO2 converted to NO NO NO Valves Excess Ozone NO Cycle NO Cycle passes sample air to reaction chamber Ozone reacts with NO Only NO reacts – NO2 isn’t measured NO2 is calculated: NOx – NO = NO2 Ozone generator Dry filtered air hv in reaction cell is measured by PMT

Gas Phase Titration (GPT) – Creating a NO2 test atmosphere CFR Title 40 Part 58 Appendix A 3.2.2.2  (a) NO2audit gas for chemiluminescence-type NO2analyzers must also contain at least 0.08 ppm NO. NO concentrations substantially higher than 0.08 ppm, as may occur when using some gas phase titration (GPT) techniques, may lead to evaluation errors in chemiluminescence analyzers due to inevitable minor NO–NOXchannel imbalance. Such errors may be atypical of routine monitoring errors to the extent that such NO concentrations exceed typical ambient NO concentrations at the site. These errors may be minimized by modifying the GPT technique to lower the NO concentrations remaining in the NO2audit gas to levels closer to typical ambient NO concentrations at the site. [This is in the Annual Performance Audit Section, but is relevant to GPT] In the next slide, [Norem] should be at least .080 ppm, but not be excessively higher than that

Gas Phase Titration (GPT) NO2 actual = % NO2 Converted NO2 expected

Some Other Important CFR Requirements QMPs/QAPPs/SOPs a must Independent quality management Establishment of a Primary Quality Assurance Organization Use of NIST Traceable Standards Use of FRM/FEMs at the appropriate operating ranges and with appropriate settings PART 53—Ambient Air Monitoring Reference and Equivalent Methods Siting, Probe placement & acceptable probe materials Appendix E to Part 58—Probe and Monitoring Path Siting Criteria for Ambient Air Quality Monitoring Appendix D to Part 58—Network Design Criteria for Ambient Air Quality Monitoring AQS submittal and annual data certification 58.15   Annual air monitoring data certification 58.16   Data submittal and archiving requirements

SO2 Validation Template continued

NO2 Validation Template continued

CO Validation Template continued