
Step 3: From Estimates to Measurement
The imperative of understanding your Greenhouse Gas emissions and how that defines what’s possible.
June 8, 2022
By: Melissa Dakas, Terence Trefiak, Shawn Nelezen, & Patrick Clark
THE THIRD IN A FIVE-STEP BLOG SERIES
In previous steps, we recently discussed greenhouse gas (GHG) reporting frameworks, what they mean for your organization, and how they can help you meet your goals and standardize your reporting – while demonstrating your commitment to ESG for your community and shareholders. In this step, we’re going to talk about how important it is to fully understand your GHG emissions and some of the technologies that can help you accurately measure them.
Types of Emissions
Scope 1, 2 and 3 Emissions
A company’s GHG emissions can be divided into three scopes. Scopes 1 and 2 are most commonly calculated and reported, and they represent direct emissions from a company’s operations along with the indirect emissions from energy resources like electricity used in their operations. Scope 3 emissions are indirect emissions that occur in the value/supply chains of the reporting company. Fewer companies calculate Scope 3 emissions, which can be difficult to obtain and monitor.
Testing Methods and Technologies
Estimating GHG emissions has been primarily achieved using emission factors, which are representative values for the amount of a pollutant released to the atmosphere from a specific type of activity. Recent studies have shown that many published emission factors do not accurately represent actual quantities of GHG emissions. These emission factors can be averaged values while the real values can range widely or conservatively to ensure the actual emissions will almost always be lower. When a GHG inventory is based only on emission factors, it is difficult to demonstrate a reduction in emissions from improvements to equipment performance and operating practices. Often, a reduction in reported emissions is from minimizing the activity, completely eliminating the source, or from the divestment of assets.
To determine accurate, transparent GHG emissions, direct monitoring and measurement programs need to be deployed. As these more robust and accurate sampling and testing methods are developed, the sensitivity and overall accuracy of sampling and reporting have been steadily increasing. Where continuous, direct measurement isn’t possible, companies are implementing measurement programs to periodically measure a statistically significant/representative population of the emission sources and develop site and source specific factors that more closely align with reality. This allows for more accurate reporting and better information for making decisions around reductions. Here at Montrose, we have been at the forefront of these emerging technologies, which provide a perfect companion to older, more traditional methods. Some of these technologies are listed below.
Fourier Transform Infrared Spectroscopy (FTIR)
FTIR is an analytical technique that has been applied to source monitoring. Extractive FTIR monitoring removes gas from the stack or duct, filters out particulate matter, and transports the gas through a sample line to a remote location for continuous, real-time analysis by an FTIR spectrometer.
This multi-component, real time measurement is a trusted technique for gaseous hazardous air pollutants (HAPs), volatile organic compound (VOC) emissions, and non-organic volatile compounds from stationary sources. FTIR can potentially identify and quantify any gas that absorbs infrared light, and the system can measure hundreds of HAPs.
Leak Detection & Repair (LDAR)
LDAR inspections of process components can be done using the traditional EPA Method 21 or newer technologies like Optical Gas Imaging (OGI), which offer more coverage with greater efficiency. There are a growing number of innovative approaches to fugitive emission management enabled by advanced equipment and technology, such as vehicle and drone-based detection/triangulation and real-time sensor arrays that offer immediate leak response. Traditionally, leak rates are calculated using ppm readings and correlation emission factors that can significantly underestimate large leaks. There are technologies that can provide an actual direct measurement of the flow rate of each leak (e.g., hi-flow sampler, thermal mass and vane anemometer flow meters, and volumetric bagging).
Data QA/QC
All the sampling conducted is only as good as the data it collects. Our AirSense platform interfaces with multiple air, water, and soil data sources to provide an integrated environmental solution with advanced data analytics capabilities. Coupled with experienced and highly trained operators, such a capability greatly reduces data errors and provides more usable, actionable data.
What’s next?
We’ve touched on the types of emissions you need to be aware of and account for, as well as the various emerging technologies that can help you more accurately measure and react in a timely fashion. In our next step, we’ll talk about the power and importance of data, and how it can help you improve your decision-making capability. If you have any questions or comments about this step or anything else, just contact us below. We look forward to the continued conversation on this important topic, and we stand ready to assist you and your organization with getting on the path toward achieving your GHG reduction goals.
The 5 Steps to Making Your Company’s GHG Reduction Goals a Reality

MEASUREMENT:
From Estimates to Measurement: The imperative of understanding your greenhouse gas emissions and how that defines what’s possible.
MEASUREMENT Co-Authors
Melissa Dakas
Principal – Environmental Advisory Services
Ms. Dakas has 20 years of project management and solution development experience in the chemical engineering and environmental compliance fields. The last 15 years of her career have been spent in environmental consulting navigating the complex environmental requirements of the Northeast states, the Caribbean, and the Texas Gulf Coast Regions. Ms. Dakas specializes in air permitting and compliance through working with both industry and government to implement business objectives while conforming to environmental regulations.
Terence Trefiak
SVP, LDAR North America
Terence Trefiak brings over 20 years of industry experience to the Montrose team where he currently serves as Senior Vice President of LDAR, North America. Prior to joining the Montrose team, Terence worked in various Engineering positions for companies such as ConocoPhillips and BJ Services. He is an expert in fugitive emission management and specializes in providing clients with advanced emission reduction technologies for GHG and LDAR compliance. Terence is a Registered Professional Engineer in Alberta, Canada and is a member of the Association of Professional Engineers and Geoscientists of Alberta. In 2016, he received recognition from Ernst and Young as Entrepreneur of the Year in Canada. Terence holds a Bachelor’s of Science Degree in Chemical Engineering from the University of Calgary.
Shawn Nelezen
SVP, Stack
Shawn Nelezen is the Senior Vice President of Air Quality Services at Montrose Environmental. He has been with the company for 4 years. He began as a Field Technician in 1998 at Mostradi Platt and later became an Account Manager for The Avogadro Group, LLC where he provided technical oversight and on-the-job training to project managers and technicians. Avogadro was acquired by Montrose in 2014.
Patrick Clark
VP, Ambient and Emerging Technology
Patrick Clark brings over 25 years of industry experience to the Montrose team where he currently serves as Vice President of Ambient Air and Emerging Technology. Prior to joining the team, Patrick was the President and Founder of Airtech Environmental Services, Inc. He is a Registered Professional Engineer and served as Chair for various industry specific conferences. As a subject matter expert, he has spoken and served as session chair at numerous technical conferences for the industry. Patrick holds a Bachelor’s of Science Degree in Chemical Engineering.