Particulate Air Contaminants and Particulate Contaminant Removal Equipment
ASHRAE Technical Committee 2.4

Scope of TC 2.4

TC 2.4 is concerned with the nature of particulate contaminants, both solid and liquid; the measurement of their properties; their effects on living things and materials; both solid and liquid; the means of removing unwanted particulate contaminants from gases; and the evaluation of the effectiveness, energy usage, and economy of such purification equipment. The TC is concerned with the effects of particulate contaminants on the quality of air supplied to and exhaust from enclosed spaces, and with the sources of particulate contaminant pollution within such spaces. The scope of TC 2.4 does not include purely physiological or toxicological aspects of particulate pollution, which are the province of TC 2.1 and TC 2.2.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years.

ASHRAE Handbooks are the root source books for the HVAC&R industry around the world.  Information in these books encompasses everything necessary for good application of HVAC&R engineering techniques.  The Handbook Subcommittee is charged with adding, revising and updating sections of these books pertaining to air filtration.

The Handbook can be purchased at the ASHRAE Bookstore by clicking on this link.

This TC is responsible for the following chapter in the HVAC Systems & Equipment Volume

Air Cleaners for Particulates
This chapter discusses removal of contaminants from both ventilation and recirculated air used for conditioning building interiors. Complete air cleaning may require removing of airborne particles, microorganisms, and gaseous contaminants, but this chapter only covers removal of airborne particles and briefly discusses bioaerosols. Chapter 46 of the 2011 ASHRAE Handbook—HVAC Applications covers the removal of gaseous contaminants.

Comment on the Handbook: ASHRAE welcomes your comments on the Handbook or a specific Handbook chapter.  To submit a comment about any aspect or part of the Handbook series, you can use the Handbook Comment Form.

Review a Handbook Chapter: To provide your feedback about a specific Handbook chapter, you can answer the brief survey questions on the Handbook Chapter Review Form.


Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting.

The Program Subcommittee puts forward programs and seminars at ASHRAE’s two conferences per year to help educate the engineering and end user public about proper air filtration and latest information on filtration.  Through Forums, Seminars, and Conference papers, the Program Subcommittee presents the educational arm of TC2.4.

ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.


Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.

The Research Subcommittee is responsible for pushing forward ideas and areas that advance the art and science of air filtration.  These programs require research by scientist that provides conclusions substantiated with fact.  Research money from the ASHRAE Research Foundation is used to fund this research.

This TC has the following active research projects:

1734-RP: Reproducing a Representative Urban Atmospheric Aerosol Distribution at High Concentration in the Laboratory for Air Filter Ageing to be used in ASHRAE GPC 35P for Determining the Energy Consumption Caused by Air Filters - This research will develop an effective, repeatable and reproducible method for laboratory generation of a synthetic aerosol having the same particle size distribution of typical urban aerosols but at much higher concentrations for use in artificial ageing tests. Such aerosol is needed to obtain realistic information about the loading and evolution of air filter pressure drop over its service lifetime. The accomplishment of this goal would allow the calculation and reduction of energy consumption caused by HVAC air filters by providing a method to ascertain particular filter air flow resistance during its service life, for both current and future filter designs.

1756-RP: Evaluation of particle sensors for indoor air quality monitoring and smart building systems - Airborne particulate matter (PM) is considered to be one of the most important indoor pollutants for human health in both residential and commercial buildings worldwide. Real-time particle sensors, which are becoming increasingly more available and affordable, offer promising uses for informing occupants on indoor air quality (IAQ) and moving towards smarter control of building systems. However, challenges remain regarding the practical use of lower cost PM sensors in smart building applications, primarily because of a lack of information on sensor performance metrics, including data sets comparing their accuracies and other technical criteria to high quality data measured with laboratory-grade instrumentation. There remains a need to inform the HVAC engineering community on the availability, costs, effectiveness, usability, hardware compatibility, and overall practicality of commercially available PM sensors for IAQ monitoring and system controls in both residential and commercial buildings. Therefore, the objectives of this proposed research are to fully test and document the performance of a large number of commercially available PM sensors and to provide recommendations for developing ASHRAE standards and guidelines for evaluating their performance for IAQ monitoring and smart building systems applications. Specific tasks are to: (1) determine what levels of accuracy and other performance criteria would be acceptable for various IAQ and smart building applications; (2) review and catalogue a variety of PM sensors commercially available on the market, focusing mainly on low and medium cost PM sensors that are currently available; (3) conduct laboratory evaluations of the performance of these sensors relative to highly accurate research grade equipment using realistic indoor and outdoor PM concentrations and sources and to perform hardware compatibility checks with building automation communication protocols (i.e., BACnet); and (4) provide recommendations for developing a future ASHRAE standard or guideline for evaluating the performance of indoor PM sensors and their compatibility with smart building systems.

1784-RP: Repeatability and reproducibility assessment of ASHRAE Standard 52.2 as currently amended. ASHRAE Standard 52.2 – Method of Testing General Ventilation Air Devices for Removal Efficiency by Particle Size was issued in 1999 and it is under continuous maintenance. The main goal of this project is to evaluate the repeatability and reproducibility of ASHRAE Standard 52.2-2017, and to identify additional sources of variability. This project will test selected commercially available particle air filters to validate recent changes to ASHRAE Standard 52.2. The PI will procure, pre-test and distribute the filters, coordinate laboratory testing, and analyze the results to form conclusions and recommendations. Because Standard 52.2 is under continuous maintenance for continuous improvement, the results from this project will contribute directly to improving reliability and credibility of ASHRAE Standard 52.2.



ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

The focus of the Standards Subcommittee is on the writing and continued maintenance of standards and guidelines written for HVAC&R air filtration.  This group not only reviews ASHRAE standard and guidelines but also keeps an active reporting system of HVAC&R standards and guidelines produced by other organizations and other countries around the world.

This TC is Cognizant for the following standards

ANSI/ASHRAE Standard 52.2: Method of Testing General Ventilation Air Cleaning Devices for Removal Efficiency by Particle Size
ANSI/ASHRAE Standard 185.1: Method of Testing UVC Lights for Use in Air Handling Units or Air Ducts to Inactivate Airborne Microorganisms.

This TC is CoCognizant with TC 7.3 lead for the following standard

ANSI/ASHRAE/ACCA 180: Standard Practice for Inspection and Maintenance of Commercial-Building HVAC Systems


The scope of the Planning Subcommittee is to evaluate and propose methods for improving the operations of TC 2.4 and its subcommittees.  This would include recommendations to the committees on "How" and "Why" we are operating as committees, ways to improve participation in TC 2.4 activities, and future activities and direction of the committees. The focus of the planning committee is not intended to be "What" we have done in the committees.


The Publication Subcommittee strives to produce articles for the ASHRAE publications of “Insights” and “The ASHRAE Journal.”  Normally, all research funded by ASHRAE includes a published article on the criteria and outcome of the research and this is published in “The ASHRAE Journal.”  This committee is responsible for soliciting and writing articles for publication.

Other Activities

TIP: If MTG involvement add here otherwise leave blank.

This TC is a member of the following Multidisciplinary Task Groups

MTG.BIM: Building Information Modeling
This MTG will coordinate the activities of multiple TC/TG in the area of standards and approaches to support the implementation of BIM within ASHRAE products and within the industry workplace.  MTG-BIM will also represent ASHRAE interests within the BIM marketplace outside of ASHRAE and provide a conduit for funneling information about the BIM industry to ASHRAE members.

MTG.ACR: Air Change Rate - coordinate TC/TG/TRG/SSPC technical activities to help evaluate the technical basis and adoption of airflow rate specifications in terms of Air Change Rate (ACR) or Air Changes per Hour (ACH) for spaces such as cleanrooms, laboratories, patient rooms, operating rooms, and other similar spaces.  Responsibilities include suggestions for research, development and presentation of technical programs for all types of spaces which currently require ACR specifications, and a special publication detailing aspects of the ACR philosophy and practice. The work of this MTG will potentially impact design guidelines, ASHRAE Handbook, and related ASHRAE standards. This MTG intends to involve other national and international groups and organizations in these efforts.

MTG.IAST: Impact of ASHRAE Standards and Technology on Energy Savings/ Performance - MTG.IAST will generate research proposal(s) and work with the selected consultants/contractors to conduct research, collect and organize the data in a useful and conveniently summarized format for Initiative 1B of the Society Strategic Plan  “ASHRAE will research the true impact of its standards and technology” as requested by the BOD.


ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at

This TC is responsible for the following Frequently Asked Questions:

What is ASHRAE's recommendation for residential filtration? (2)
What level of filtration is recommended for my application? (11)
What is ASHRAE's recommendation on the use of filters with microbial inhibitors? (22)
What is ASHRAE's recommendation on the use of ultraviolet light in air systems for microbial control? (23)
What research is ASHRAE conducting regarding air filtration? (48)
I am manufacturing a filter. Can ASHRAE test and certify the filter? (49)
What are ASHRAE's recommendations for filtration efficiency for commercial applications? (61)
What are ASHRAE's recommended filtration efficiencies for medical applications? (62)
How are HEPA filters certified? (68)