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Program Description

The BreatheScore Accredited Professional (BAP) Program is a comprehensive training and certification program designed for test and balance engineers, and HVAC or facilities professionals seeking to learn how to run ASHRAE Standard 241-2023 clean air tests, and to enhance their skills and knowledge in the application of tracer particle decay methods.


These methods are employed to measure non-infectious air delivery rate metrics within building zones, such as effective air change rate (eACH),  Equivalent Clean Airflow rate (ECAi), and Volumetric Equivalent Clean Airflow Rate (VECAi).

The program focuses on providing individuals with the necessary expertise to measure ventilation and filtration effectiveness in various building types, contributing to healthier and more sustainable environments.

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The BAP Program covers theoretical foundations, practical applications, and advanced techniques for measuring air delivery rate metrics using tracer particle decay methods. 


The program incorporates both online and hands-on training modules (done at home), simulation exercises, and real-world case studies. The curriculum also addresses relevant new standards (e.g. ASHRAE Standard 241-2023) and guidelines, governing ventilation and filtration systems.

Goals and Outcomes

Upon successful completion of the BAP Program, participants will:
  • Gain a basic understanding of the goals and scope of ASHRAE Standard 241-2023.

  • Gain a thorough understanding of tracer particle decay methods and their application in measuring non-infectious air delivery rate metrics for building zones.

  • Develop skills to accurately evaluate and optimize ventilation, filtration and clean air clearance, ensuring compliance with guidelines and best practices.

  • Learn how to identify potential issues and provide solutions for improving airborne infection control and energy efficiency in various building types through ventilation and filtration effectiveness measurements.

  • Receive a BreatheScore Accredited Professional Certificate, demonstrating their proficiency in utilizing tracer particle decay methods for assessing building ventilation and filtration systems.

  • Enhance their professional expertise and credentials in the field of HVAC and facilities management, contributing to career advancement and increased demand for their expertise and services.

The BAP Program aims to empower HVAC and Facilities professionals with the specialized knowledge and skills required to effectively utilize tracer particle decay methods in their practice, ultimately contributing to healthier, more energy-efficient, and sustainable built environments.


BreatheScore Accredited Professional Program Modules



Program Foundations

Approximate time to complete: 15 minutes.

Required reading. You will be tested on this theoretical knowledge during the written test you will be required to pass to complete the BreatheScore Accredited Professional Program.


Training Videos

Approximate time to complete: 1 hour

A series of four training videos that cover BreatheScore test concepts, materials and protocols.

After watching the videos, you'll also be provided access to download the BreatheScore Field Guide.


Kit Set Up & Practice Session

Approximate time to complete: 1.5 hours

Schedule & attend a virtual training session with your BreatheScore Program Manager. 


Knowledge Test

Approximate time to complete: 15 minutes

Earn your Program Certificate by passing the written knowledge test with a 100% grade.

Program Foundations

What is a BreatheScore Test? 

Poppy BreatheScore Tests provide the most direct and accurate way to measure the contribution of all investments in air safety. With a quick air safety test, Poppy measures each room’s equivalent clean airflow, including outdoor air and recirculated air, portable air cleaners, filters and other technology.

Poppy BreatheScore Tests measure compliance with the new ASHRAE Standard 241-2023 standard for control of infectious aerosols using effective Air Changes per Hour (eACH) and Equivalent Clean Airflow Rate per person (ECAi) providing insights on the safety of spaces, the tools to improve if needed, and the resources to communicate with occupants.

How do BreatheScore Tests work? 

Poppy BreatheScore Tests use four small Sensors and one Nebulizer to measure how quickly particles emulating the behavior of respiratory viruses present in human breath are cleared from indoor spaces.

Poppy Nebulizers release small quantities of a water-based tracer solution into the air within key zones of each building. 

Poppy’s advanced sensors instantly measure and trace how these aerosols move within rooms, between rooms and how quickly they are cleared. They also provide detailed metrics and insights for air system optimization. 

How do BreatheScore Tests work? 

The test automatically guides you through the following stages of measuring particle-level airflow rate:

  1. Background - measuring background level of particles in the air

  2. Nebulization (Release) - increasing the volume of particles in the air using the Poppy Nebulizer and allowing them to mix with airflow in the space

  3. Capture (Settling & Decay) - measuring the rate at which particles are removed from the air

  4. Results - automatic calculation of the key test metrics and report


How do particles travel in a room?

Particles released from a source (humans or external sources) can travel through the air based on diffusion or other airflow patterns present within that space. These aerosolized particles can linger in the air or get cleared quickly depending on the conditions within the room and the HVAC system present. Some factors that affect the ability to clear particles include the airflow of the room, ventilation and filtration, HVAC system, in-duct air filters, air cleaners, temperature, humidity, and numerous other factors.

How does an HVAC system work?

A heating, ventilation and filtration, and air conditioning (HVAC) system is designed to provide thermal comfort and indoor air quality in buildings. The HVAC system regulates temperature by generating or removing heat from the air and circulates this air throughout an indoor space. Additionally, the system can dilute by mixing in outdoor air, and filter air that is being recirculated within the building to remove contaminants from the air.


Why are ventilation and filtration important?

Good ventilation and filtration is essential for maintaining a healthy indoor environment and reducing the spread of respiratory infections. Improving ventilation and filtration (moving air into, out of, or within a room) and filtration (trapping particles on a filter to remove them from the air) helps to dilute and remove airborne pollutants, including bacteria, viruses, and other pathogens, from indoor air. It also helps to regulate indoor humidity levels, which can further reduce the spread of infectious diseases. Poor ventilation and filtration can lead to a buildup of harmful contaminants in indoor air, which can cause respiratory problems, allergies, the spread of respiratory pathogens and other health issues. Adequate ventilation and filtration is especially important in buildings where large numbers of people gather, such as schools, hospitals, and office buildings, where the risk of respiratory infection transmission can be high.

Why is measuring ventilation and filtration important? How does it affect occupant health, energy use, and operating costs?

You can’t improve what you don’t measure. Experts agree that respiratory-based viruses like COVID-19, Flu, and RSV are contracted through breathing in viral particles and recommend a minimum of 5 air changes per hour to reduce airborne infection risk. ASHRAE 241-2023 is a more detailed standard that takes into account how many people typically occupy a room, the volume of the room, and how a room is used. Poppy provides the most direct and accurate way to measure the contribution of all investments in air safety and provide insights on how infection-resilient a space is.


Measuring eACH can be an effective tool for improving energy and cost efficiency in over-ventilated buildings. Over-ventilated buildings can result in higher energy costs and unnecessary wear and tear on HVAC systems. By measuring eACH, building managers can assess the amount of ventilation and filtration required to maintain low respiratory infection risk, while minimizing energy consumption and associated costs.


Measuring ECAi (equivalent clean airflow per person that includes the impact of ventilation and filtration) helps buildings assess their current respiratory pathogen risk levels and adjust their HVAC systems accordingly. Areas that are low occupancy will need less clean air than those that are typically highly occupied.


What is Equivalent Clean Airflow Rate (ECAi and VECAi)?

Equivalent Clean Airflow (ECAi) represents the airflow rate of clean, pathogen-free air needed per person in the breathing zone in order to achieve a low infection risk in indoor environments. It is expressed as cubic feet per minute per person (cfm/person), or liters per second per person (L/s/person). 

Volumetric Equivalent Clean Airflow, VECAi, is the minimum Equivalent Clean Airflow rate required for a space based on the number of occupants. This is expressed as cubic feet per minute (cfm). If there is a difference between the actual VECAi and the target VECAi value this is depicted as the Volumetric Flow Differential and indicates if adjustments need to be made: if it is a positive value the space could be “overventilated” and if it's a negative value, it indicates the gap to overcome in order to meet Standard 241 at the current occupancy.

ASHRAE Standard 241-2023 serves as a comprehensive guideline, specifying the minimum Equivalent Clean Airflow required for a range of indoor space types, contingent upon their designated purpose and usage. These values are carefully determined to optimize indoor air quality, ensuring safer and healthier environments for occupants by reducing the risk of airborne transmission of infections.

To meet ASHRAE Standard 241-2023, a minimum of 20 to 90 cubic feet per minute (cfm) of equivalent clean airflow per person is required, depending on the type of space, e.g., office vs. home vs. medical waiting room.  Note: these rates are doubled if “group vocalization above a conversational level” is involved (think singing or cheering).  Also note that for residential separation areas for infected occupants or with vulnerable  populations, rates are higher.

How are ECAi, VECAi, and Occupancy related?

Each person in a room requires a minimum equivalent clean airflow rate (ECAi), for example, 30 cubic feet of air per minute (cfm). A meeting room intended for 10 people has a total requirement (VECAi) of 300 cfm (30 *10). If occupancy of the meeting room is limited to 5 people, then half the amount of equivalent clean airflow is required.


What is captured in BreatheScore results?

Tracer particle testing, as outlined in ASHRAE Standard 241-2023, measures contributions in the breathing zone from all ways that remove particles from the air including:

  • Mechanical ventilation, filtration, and deposition, e.g., HVAC and Portable air cleaners

  • Passive (natural) ventilation, e.g., doors, windows 

Note: The contributions of pathogen inactivation technologies (that do not dilute or remove particles) such as UVC is calculated based on the manufacturer’s reported Clean Air Delivery Rate (CADR) in cfm.

What is the Breathing Zone?

The Breathing Zone is defined by ANSI/ASHRAE Standard 62.2 as 3 to 72 inches above the floor and more than 2 feet from walls or fixed air conditioning equipment. Poppy test measurements are typically taken at 40-50 inches above the floor. 

What is eACH?

Effective Air Changes per Hour (eACH) is the measure of a space's ability to clear a specific type of aerosol. eACH is related to how quickly respiratory ~1um aerosol particles (size produced during human breath) are removed and replaced with clean air by taking into account the contribution of all sources of purification, filtration and dilution (natural ventilation) within a space. Unlike ACH, eACH is a direct measurement of the performance on a ventilation and filtration system within a building, within the breathing zone (defined as 3-72 inches by ASHRAE). It is important to measure within the breathing zone as this is the air that people will breathe in and be exposed to.

What changes affect eACH?

Equivalent clean air can be achieved through natural and/or mechanical ventilation and filtration. Natural, or passive, ventilation relies on openings like windows, doors, or vents to allow outdoor air to enter and circulate through the building. Mechanical ventilation and filtration, on the other hand, uses fans, ducts, filters, and air handling units to distribute and control the flow of outdoor air.  Mechanical ventilation provides clean air in two ways: through the bringing in of outdoor air, and through the filtration or purification of recirculated indoor air. Both of these methods can remove respiratory pathogens from the air within a space. 


By measuring and understanding equivalent clean air, indoor spaces can minimize the buildup of pollutants, remove odors, control humidity levels, and maintain an overall healthier indoor environment. This is especially important in buildings where the windows cannot be opened or in areas with poor outdoor air quality due to factors like pollution, allergens, or extreme weather conditions.

How does Poppy’s tracer technology work?

Poppy uses a patented tracer particle system and consists of three components used in the BreatheScore Test:

  • Poppy Tracers: These water and salt tracer particles are integral to the system, emulating the behavior of respiratory viruses present in human breath. By closely resembling real viral particles, they provide crucial insights into the potential transmission and dispersion of airborne pathogens.

  • Poppy Nebulizers: Strategically positioned within key areas of a building's breathing zone (typically 40-50 inches above the floor), Poppy Nebulizers dispense controlled quantities of the Poppy Tracer solution into the air.

  • Poppy Sensors: Once released into the air, the tracer particles are monitored and tracked by Poppy Sensors. These advanced sensors continuously detect and measure the movement of the tracer particles in real-time. As a result, the system can precisely assess how the tracers disperse and are cleared from the air.


This data is used to calculate eACH, ECAi and VECAi within minutes in each tested location. This data provides valuable insights into the air circulation and ventilation and filtration performance within the building. The entire process is streamlined and efficient, with results being relayed within minutes through a secure cloud connection within the Poppy App and via email.

When should I use Poppy’s tracer technology?

Poppy’s tracer technology can be used in any indoor location where you want to test the level of ventilation and filtration and effectiveness of the HVAC system. Each test measures a “zone” which is defined by an area or room up to 900 sq ft and is typically performed quarterly based on changes in season or HVAC updates. These scores provide insights on the safety of spaces, the tools to improve if needed and ability to schedule additional tests. By observing eACH changes over time, Poppy’s tracer technology helps ensure that spaces continue providing healthy indoor air for occupants and reducing the potential for spread of respiratory infection. 


What are some examples of ways to reduce risk from airborne infections in an indoor space?

There are many types of improvements that can be made once you know how each part of your building is currently performing:

  • Ventilation (Dilution): Bring in more fresh air to increase the outdoor air percentage (OA%) and improve aerosol clearance. 

  • Filtration: Add portable HEPA purifiers in zones with poor clearance, upgrade to MERV-13 filters, or if MERV-13 or better filters are in place increase recirculation rates.  Note: After 1/1/25, ASHRAE 241-2023 requires that the minimum filter efficiency is a MERV-A 11 or an ISO 16890 ePM2.5 50% filter.  

  • Purification: Air purification includes a set of newer technologies, e.g. UVC, the efficacy of some are still under study.

  • Space Use & Containment: Reduce occupancy levels or change how a space is used (from high-risk activities to low risk activities).

Training Videos

Introduction to BreatheScore

BreatheScore Kit Materials

BreatheScore Deployment

BreatheScore Post-Deployment

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Download the BreatheScore Accredited Professional Field Guide

The BreatheScore Accredited Field Guide includes Advanced Topics & Troubleshooting Content. The Guide is updated on a semi-regular basis. BreatheScore Accredited Professionals will receive updated versions via email as they become available.

Kit Set Up & Practice Session

Schedule your 1.5 virtual training session with your Program Manager below, only after you have completed the previous modules and have received your BreatheScore Kit.

This is a mandatory training session.

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Knowledge Test

Once you have attended your Kit Set Up & Practice Session virtual training you will be emailed a link to complete the written Knowledge Test.

  • This written test should take approximately 15-30 minutes to complete

  • You are required to answer 100% of the questions correctly to pass

  • You may complete the test as many times as needed to achieve the required 100% pass rate

Have any questions or need support?
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