Adelaide Exposure Science and Health
Our ref OEHC1156
Mr. Jon Taylor
Airofresh Intl
34 Glen Osmond Rd,
Myrtle Bank
South Australia 5064
Date: 3 July 2020
Dear Jon
Re: Testing of the Airofresh Oxidation Unit
Please find attached the report on the testing of the Airofresh Oxidation Unit (OU) with
formaldehyde.
Yours sincerely
Dr Joe Crea
BSc(Hons), PhD, FAIOH
Senior Occupational Hygienist and Research Officer
Dr Michael Tkaczuk
BSc(Hons), PhD, Grad Dip Occup Health
MAIOH COH MRACI
Senior Occupational Hygienist and Research Officer
1. PROJECT REVIEW DOCUMENT
Testing Conditions for the Evaluation of Airofresh Oxidation Unit (OU) with Common Air
Contaminants
Dr, Joe Crea FAIOH, Dr Michael Tkaczuk MAIOH COH
The University of Adelaide; School of Public Health, Faculty of Health and Medical Sciences
Adelaide Exposure Science and Health Laboratory (formally Occupational & Environmental
Hygiene Laboratory)
The University of Adelaide, 28 Anderson Street THEBARTON SA 5031, Adelaide, Australia
Duration of Research: February to June 2020
Research Report Date: 26 June 2020
SCOPE:
The purpose of this study was to independently evaluate the performance of a n Airofresh
Oxidation Unit (OU) on the removal of low concentrations of formaldehyde a in indoor
environments.
The test protocol was to create a realistic and standard environment as for Heating,
Ventilation, and Air Conditioning (HVAC) setup requirements. The technology acceptance
testing and validation was carried out in the environment for which the technology is intended
to be used.
Testing and analysis were undertaken by the Adelaide Exposure Science and Health
Laboratory at The University of Adelaide has been impartial and subject to a systematic
evidence-based assessment process. There are no competing or conflicting interests to
declare.
2. TESTED AIR POLLUTANTS:
• Formaldehyde: is commonly found in indoor air and has been used, as a component
in building materials (e.g. particle board, furniture), adhesives and insulation
materials. It is also used in the health care industry as a disinfectant and biocide and
a tissue fixative and embalming agent.
o
3. SYSTEM TEST CONDITIONS
The unit tested was an Airofresh Oxidation Unit (AF1000 – see Figure 5) to determine the
effectiveness of the removal of air contaminants is shown in Figure 1 operating at 240VAC
The Airofresh Oxidative unit was placed in line using 200 mm diameter flexible HVAC
ducting.
The Airofresh Oxidative Unit was tested with the air flow operating at the pre-set motor
velocity which was measured as 2.2 metres per second.
Testing was carried out using low and high concentrations of the chosen air contaminant.
The exhaust air from the in-line fan unit was fed into an operating Laboratory fume
cupboard.
The temperature and operating conditions have remained consistent throughout all
experiments and test processes, that is the air temperature was 22oC, relative humidity 4050%, carbon dioxide concentration 500 - 600 ppm.
Vapour/gas concentrations were collected/measured before (Pre) the unit and after (Post) the
Airofresh Oxidative unit. Samples were collected inside the flexible ducts with the Unit
operating with the air contaminant being present.
Airflow: measured a 2.2 metres per second
Temp 22 - 24oC; Relative Humidity 40- 50%
Carbon Monoxide (CO concentration) < 0.1 ppm
Carbon dioxide concentration CO2 500 – 600 ppm
Guidance Data used to test formaldehyde
The concentration range selected for this study used the following guidelines;
‘Safework Australia Workplace Exposure Standard for Airborne Contaminants’
and ‘NHMRC Goals for Maximum Permissible Levels of Pollutants in Indoor Air’.
This document has been rescinded but not replaced by any Australian guideline.
The recommended formaldehyde level in this guideline is 0.1 ppm. World Health Organisation (WHO) and the
National Industrial Chemical Notification and Assessment Scheme (NICNAS) recommend a value of 0.08
ppm. The VOC recommendation by the rescinded NHMRC guideline is 0.5 mg/m3
The experimental limitations for determining the concentration range was the injection rate of
the of the Syringe Pump (Figure 4) and the sample size of the air contaminant required for
the analysis using High Pressure Liquid Chromatography (HPLC) for formaldehyde.
Testing was done as a single pass continuous test.
4. MEASUREMENT OF AIR CONTAMINANTS
For formaldehyde, a pre-weighed amount of para-formaldehyde was placed in an aluminium
tray inside an insulated open-ended steel chamber with a glass wool filter over the end to
stop any paraformaldehyde dust being released (Figure 3). The para-formaldehyde was
heated using a heating block at set temperatures to be able to generate the required
concentrations of formaldehyde in the flexible ducting. Samples of air were collected onto 2,4
dinitrophenyl hydrazine coated glass fibre filters connected to personal air sampling pumps
set to 1.0 L/min flow rates to measure the concentration of formaldehyde vapour inside (at
about the centre) the flexible duct (see Figure 1 for sample location).
The analysis of the collected formaldehyde samples was carried out by a verified method for
formaldehyde; ‘Health & Safety Executive (HSE), Method for determination of Aldehydes in
air (MDHS 102)’ that utilises a high-performance Liquid Chromatography (HPLC) Ultraviolet
(UV) analysis.
The testing was carried out at room temperature (22oC to 24oC) and RH of 40% to 44%
5. RESULTS
Formaldehyde
Table 1 Airofresh Oxidative Unit testing with a variety of Formaldehyde concentrations
Sampling
Time
(mins)
66
60
60
32
15
Concentration
of formaldehyde
generated
Pre-Unit
0.009
0.017
0.020
0.049
0.374
Concentration
of
formaldehyde
Post Unit
0.0039
0.0088
0.0120
0.0280
0.275
Efficiency of Unit
removing
formaldehyde
57
48
40
43
27
Comments
ran at RT
ran at RT
ran at RT
ran at RT
heated to about 50oC
6. Discussion
Testing of the Airofresh unit was carried by testing before (Pre) and after (Post) the Unit by
generation concentrations of Formaldehyde. The concentrations generated were the lowest
concentrations based on the settings of the Syringe pump unit and sensitivity of the
analytical method. The concentrations generated were comparable to typical general
environmental concentrations.
The formaldehyde testing gave the largest reduction of 57% at the output of the Airofresh
unit, at a generated formaldehyde concentration of 0.009 ppm, as seen in Table 1.
From the table there is a trend of greater efficiency of the Airofresh unit as the generated
concentration of formaldehyde decreases. Background formaldehyde concentrations in
office environments in our experience, range from 0.002 ppm to 0.06 ppm. The
Formaldehyde concentrations generated to test the Oxidative Unit is within the measured
concentrations in office environments.
Therefore, based on these results, it appears that no formaldehyde is generated and the
background formaldehyde concentration in the laboratory is reduced Post the Oxidative
Unit treatment.
FIGURE1: Airofresh Oxidation Unit set up for testing
Directionof
airflow
Sampling po int
before unit
Sampling po int
after Unit
Airofresh Unit
FIGUR
E5: AF 1000 Oxidation
Unit with Serial Number
FIGURE3: Formaldehyde vapour
generation (heating
paraformaldehyde on hotplate)
FIGURE4: Syringe pump - used to
automatically inject voc at known selected
rates