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 project:

The purpose of this work is to model the impacts of HVAC filtration (i.e., MERV) on size-resolved and time-varying indoor concentrations of particles of outdoor origin (10 nm to 10 μm) in typical residential buildings located in a range of six climates in the U.S., all using the best available data for all input parameters.


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 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

MTG.ACR will 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)