
The Environmental Protection Agency’s (EPA) Residential Air Cleaners, a new technical summary report recently released, is sure to bring increased awareness to the contractor community and end-users regarding ozone.
The EPA’s 75-page, comprehensive document (www.epa.gov/iaq EPA 402-F-09-002) on the strategies, advantages and disadvantages of all residential air cleaner methodologies has gone on record and stated that ozone-generating models are detrimental to homeowners’ respiratory tracts, lungs and general health.
Prior to the EPA document’s release, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) had already taken a similar position on ozone-generating residential air cleaners and their detriment to occupant health. ASHRAE’s 2015 publication “Position Document on Filtration and Air Cleaning” states in Section 2.6, “Ozone is harmful for health and exposure to ozone creates risk for a variety of symptoms and diseases associated with the respiratory tract; Ozone emission is thus undesirable.” Section 3.2 of the document further states, “Devices that use the reactivity of ozone for the purpose of cleaning the air should not be used in occupied spaces because of negative health effects that arise from exposure to ozone and its reaction products.”
Still, other organizations have carved out regulatory ozone requirements for consumers. For example, the the U.S. Food and Drug Administration (FDA) was the first to set an ozone emissions limit of 0.05 ppm (50 ppb) for all medical devices. In 2008, the California Air Resources Board (CARB) targeted ozone emissions with a state-wide regulation requiring certification of all electronic air cleaners under UL 867’s test standard of 0.05 ppm (50 ppb) limit.
The media prominence of the EPA will help Residential Air Cleaners garner significant consumer attention in the coming months among HVAC service contractor customers. Therefore, contractors should be prepared to discuss ozone and how products they are providing may or may not be producing ozone as a primary function or as a byproduct.
Electrostatic Precipitators, Ionizers and Ozone
The EPA has stated that electrostatic precipitators (ESP) and ionizers, which are air cleaning devices positioned in the airstream of HVAC systems, as potential contributors to ozone. Both methodologies use a powered electrostatic process to charge particles, which become attracted to oppositely-charged plates or other indoor surfaces to remove airborne particulates. According to the EPA report, “Because ESPs and ionizers use high voltage to generate ionized fields, they may produce ozone either as a byproduct or by design. Ozone is a lung irritant that poses risks to health.”
The report also states that “some makes and models of ESPs and ionizers can increase indoor ozone concentrations that can even exceed public health standards.”
Some designs of another popular air cleaner methodology, ultraviolet lamp systems, may also intentionally produce ozone by design. For example, some manufacturers purposefully use specific UV wavelengths that create ozone to produce the distinct ozone odor. The air cleaners are either installed in the supply ductwork or the HVAC system plenum for airstream disinfection or near the cooling coil to also prevent mold and other biological growth.
There is no doubt ultraviolet lamp systems disinfect biological contaminants, according to equipment that passes two UVGI effectiveness test standards, ANSI/ASHRAE Standard 185.1 for UVGI lamps in in-duct airstream irradiation; and ANCI/ASHRAE Standard 185.2 for UVGI lamps for in-duct surface irradiation.
Whether or not a UVGI lamp generates ozone however, is dependent upon its wavelength. Both UVA 315-400 nanometer (nm) and UVC 100-280 nm are used in UVGI air cleaners to deactivate microorganism reproduction by altering their DNA structure.Uncoated UVC lamps at or above 254-nm do not generate ozone, whereas uncoated lamps with wavelengths below 254-nm can generate ozone through photolysis of oxygen and further reaction, according to the EPA report.
While the EPA’s report raises a red flag on ozone potential in residential UVGI air cleaners, it does not distinguish what brands and models emit harmful ozone. That raises questions for HVAC contractors who are aware that some brands may or may not generate ozone to provide their customers with IAQ solutions, and may do more harm than good.
Furthermore, many air cleaner manufacturers with designs including purposeful ozone generation began substituting their suspected methodologies with marketing terms that omit ozone descriptions. For example, the fairly popular terms 10 years ago were ozone generator and ozonator, however those terms are rarely used in air cleaner marketing materials in light of current ozone findings. This misguided marketing creates expectant and quite undesirable marketplace confusion regarding the amount of ozone generation and off-gassing emissions by several IAQ technologies, products, and brands. Consequently, consumers and even HVAC contractors, who wanted to install the safest products, had nowhere to turn for zero ozone emission confirmation.
UL 2998 Validation for Zero Ozone
Consequently, Underwriters Laboratories (UL), Northbrook, Illinois, recently took on the task of creating the desperately needed validation for zero ozone air cleaning devices. UL 2998 is the long-awaited environmental claim procedure with validation. Contractors and consumers can now visit UL SPOT (ul.com/spot), which lists all types of sustainable products worldwide. The UL SPOT’s “HVAC Air Cleaners” section lists validated zero ozone products. Qualifying zero ozone emission products must demonstrate they emit less than the maximum ozone concentration limit of 0.005 ppm (5 ppb) which is below quantifiable level for ozone testing. This is 10-fold less than permitted under test standard UL 867, which allows concentrations of 0.05 ppm (50 ppb). Approved products also receive a validation badge that can be displayed on marketing materials and product labels.
Although the EPA report targets residential systems, contractors should be aware that commercial air cleaning devices can also come under scrutiny. Consequently, specifying a zero ozone device may be the difference between winning and losing bids, especially when facility design teams recognize their importance. Zero ozone air treatment device specifications may also someday be required by green building design projects. Zero ozone air cleaning device mandates may someday be required by programs, such as Leadership in Energy and Environmental Design (LEED®), General Services Administration (GSA) Advantage, the Collaborative for High Performance Schools (CHPS), the International Green Construction Code (IgCC) and European Union guidelines and directives.
HVAC contractors can be assured ozone discussions will inevitably arise from customers that read the many reports that are surfacing in the media on the dangers of ozone emissions. It would be prudent for contractors to prepare their service people with the factual answers based on the research and refer customers to sources such as the UL SPOTwhere they will find a list of validated air cleaning devices that provide air purification with zero ozone emissions.
Aaron Engel is vice president of business development at Fresh-Aire UV (www.freshaireuv.com), North America’s largest manufacturer of residential, commercial and medical UV disinfection and carbon/titanium /PCO-based air purification systems. Fresh-Aire UV’s APCO air treatment system recently earned UL 2998 validation for emitting zero ozone. Engel can be reached at aaron@freshaireuv.com or 800-741-1195.