This document discusses collecting in-stack NO2/NOX ratio data from an existing NOx monitor at a cement facility to use in air quality modeling. It describes setting up a datalogger connected to an existing Thermo Scientific 42i NO-NO2-NOX monitor to record 1-minute readings over time. The results of this setup provided site-specific in-stack ratio data for more accurate NO2 modeling to address issues found in previous modeling attempts using default ratio assumptions. Considerations for wider application at other facilities with existing NOx monitoring are also discussed.

1. Collection of In-stack
NO2/NOX Ratio Information
March 14, 2012
Dan Dix
Technical Leader
ddix@all4inc.com
(610) 933-5246, extension 18

2. Introduction
 The collection of in-stack NO2/NOX data for use
in AERMOD’s OLM and PVMRM option has
become more important since the promulgation
of the new 1-hour NO2 NAAQS.
 Many facilities are currently collecting NOX data
using CEMS
 CEMS collecting NOX data use the
Chemiluminescence method which also
measures NO and NO2.
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3. Agenda
 Project Overview
 Current Setup
 Equipment
 Conclusions and Additional
Considerations
 Questions?
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4. Project
 Conducting exploratory 1-hour NO2 and
SO2 NAAQS air quality modeling for a
cement facility.
 NO2 NAAQS results showed issues when
using Tier III method with OLM and default
in-stack NO2/NOX ratio (0.5).
 Determine site specific in-stack NO2/NOX
ratio data using existing NOX monitor.
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5. Current Setup
 Thermo Scientific Model 42i
Chemiluminescence NO-NO2-NOX
 System currently collects NOX data on
their DAHS and PLCs.
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6. Chemiluminescence
 The Chemiluminescence process:
NO + O3  NO2 + O2 + hv
 NO and O3 react to produce a
characteristic luminescence with an
intensity linearly proportional to NO
concentrations.
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7. 42i Flow Schematic
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8. Collecting Data
 Its was easier and more cost effective to
install a temporary datalogger than set up
NO2 readings in their current DAHS and
PLC Systems.
 A Campbell Scientific CR1000 datalogger
was hooked up to unused ports on the 42i
and programmed to take 1 minute
readings of NO, NO2, and NOX.
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9. Equipment Setup
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10. Results
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11. Conclusions and Considerations
 Cost effective and simple (less invasive) way to collect
in-stack NO2/NOX information for use modeling NO2
using AERMOD’s OLM or PVMRM options.
 Many facilities currently operate NOX CEMS under a
variety of programs.
 DAHS systems could also be set up to collect this
information.
 If no NOX CEMS is in place this data can also be
collected during NOX testing.
 Protocol Considerations
• Statistical Analysis
• QA/QC
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12. Questions?
Dan Dix
ddix@all4inc.com
(610) 933-5246, extension 18
2393 Kimberton Road
Kimberton, PA 19442
All4 Inc.
www.all4inc.com
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