A PLANT MATERIAL-BASED AIR PURIFICATION SYSTEM
FOR SWINE ODOUR REDUCTION
Xuezhi Zhou
Department of Physics and Astronomy, University of Manitoba, Winnipeg, R3T 2N2, Manitoba, Canada
Qiang Zhang
Department of Biosystems Engineering, University of Manitoba, R3T 5V6, Winnipeg, Canada
Anhong Huang
Shanghai Shanke Environmental Technologies Ltd. 1288 Yecheng Rd. Jiading District, Shanghai, 201821, China
Keywords: Swine odour, Health symptom, Plant material-based air purification (PMAP), Hydrogen sulphide,
Ammonia, Pig manure, Concentration, Olfactometer.
Abstract: Environmental odour not only serves as a warning of potential health risks, but the odour sensation
themselves can also cause health symptoms , such as headaches, nausea, sore throat, cough, chest tightness,
nasal congestion, shortness of breath, stress, drowsiness, asthma, chronic bronchitis, and alterations in
mood. Swine odour consists of a mixture of volatile organic compounds (VOCs), hydrogen sulphide,
ammonia as well as particulates which adsorbed odourous compounds. A plant material-based air
purification (PMAP) system was evaluated for odour reduction in this study. The PMAP consisted of a
mixture of plant materials which emit volatiles. Measurement was performed in two identical plastic boxes
using pig manure, hydrogen sulphide and ammonia gases as odourous source. The PMAP device was placed
in only one of the boxes. The results showed that PMAP reduced the intensity of swine odour by at least
50%, the concentration of hydrogen sulphide from 20 ppm to 0.2 ppm for a pure hydrogen sulphide source
and from 0.4 to 0.02 ppm for a swine manure source. Similarly, the PMAP reduced ammonia concentration
from 29 to near 0 ppm for a pure ammonia source and from 38 to 10 ppm for the swine manure source.
1 INTRODUCTION
The impact of swine odour on the environment is
one of the major concerns to the general public.
Historically, unpleasant odours have been considered
as warning signals of potential risk to human health,
but not necessarily directly result in health effects
(Phillips, 1992; Gardner, et al., 2000). Recent studies
have demonstrated that odours may not only serve as
a warning signal of potential health risk, but odour
sensations themselves can evoke health symptoms,
including headaches, nausea, sore throat, cough,
chest tightness, nasal congestion, shortness of breath,
stress, drowsiness, asthma, chronic bronchitis, and
alterations in mood, etc. (Wing et al. 2000;
Schiffman et al., 2005;). There are at least three
mechanisms responsible for the health symptoms
caused by the odour. (1) When the concentration of
odorous compounds in the air is above the irritation
threshold, it will directly produce the health
symptoms by irritation. (2) When the concentration
of odorous compounds is below the irritation or
safety threshold but above the odour detection
threshold, many health symptoms can also occur
psychophysically. This psychophysical effect caused
by odour sensation may occur at very low odorant
concentrations. For example, H
2
S gas has a rotten
eggs smell. Its odour detection threshold ranges from
0.5 to 30 ppb while its irritation threshold ranges
from 2.5 to 20 ppm (Schiffman et al., 2005). This
means the average odour threshold of H
2
S is about
three orders of magnitude below its irritation
threshold. (3) Copollutant in an odour mixture is
responsible for some health symptoms (Donham, et
120
Zhou X., Zhang Q. and Huang A..
A PLANT MATERIAL-BASED AIR PURIFICATION SYSTEM FOR SWINE ODOUR REDUCTION.
DOI: 10.5220/0003127101200124
In Proceedings of the International Conference on Biomedical Electronics and Devices (BIODEVICES-2011), pages 120-124
ISBN: 978-989-8425-37-9
Copyright
c
 2011 SCITEPRESS (Science and Technology Publications, Lda.)

al., 1999).
How to reduce and eliminate the swine odour that
evokes health complaints and impairs quality of life
in neighbouring communities has attracted attention
of researchers worldwide. Several techniques have
been developed to reduce the swine odour emission,
such as biofiltration, ozonation, covering the manure
storage, and ultraviolet light (DeBruyn et al., 2001;
Mann et al., 2002; Riley et al., 1989; Vohra et al.,
2006).
The existing technologies have various
drawbacks. For example, it is known that the ozone
itself contributes to air pollution although ozone can
oxidize odour compounds. In other words, the use of
ozone to reduce swine odour may cause secondary
pollution. Ultraviolet light used in the pig barn over
a period of time may be harmful to both the pigs and
operators and it is also expensive. The Biofiltration
have been used to treat exhaust air from pig barns for
odour reduction, but it might cause cross
contamination if used inside the pig barns.
Plant-based aromatic materials have been used as
air fresheners in many different parts of the world
(Heath et al., 1992; Zeng et al., 2003). Recently, a
process has been developed to produce a nano-
crystalline material from extracts of several plants
(or herbs) to air purification (Zhao et al., 2006). All
the constituents in this material are naturally existing
organic materials and environmentally friendly. The
objectives of this study were to design and test a
plant material-based air purification system to verify
the efficiency of this systems in PMAP reducing the
swine odour.
2 MATERIALS AND METHODS
Two identical plastic boxes with dimensions of 64
cm X 45 cm X 40 cm were used to conduct the
experiment. Equal quantities of odour generating
materials (sources) were placed into the two boxes,
respectively. The boxes were then carefully sealed to
prevent any air exchange with the ambient. A hole
of 6 mm diameter was drilled on the center of the
box lids for taking odour measurements from the
boxes. The hole was sealed between the two
measurements. For each test, one box was equipped
with the PMAP. A small device, which includes
about 18 g of PMAP material and a micro electrical
fan to enhance the evaporation of material, was
placed into only one of the boxes. The evaporation
rate of PMAP material is about 1.5 mg per hour. The
other box without PMAP used was the control.
Two sets of tests were performed; one used pig
manure to generate odour and the other used pure
hydrogen sulphide or ammonia as the odour source.
In the first set of tests, about 80 ml of pig manure
from the Animal Research Unit of the Department of
Animal Science, University of Manitoba was
transferred into a glass bottle, and shacked for
homogeneity purposes. Then it was divided equally
into two wide mouthed glass bottles, which were
then placed into the two boxes, respectively as the
swine odour sources. In the second set of tests, the
pure H
2
S was generated by the reaction of Al
2
S
3
and
H
2
O in the wide mouthed glass bottles and the pure
NH
3
from an ammonia water solution.
An AC’ SCENT International Olfactometer (St.
Croix Sensory, Inc., Stillwater, MN, USA) was used
to measure the odour concentration of air in the test
boxes. Five panelists were selected following the EU
Standard EN 13725 (CEN 2003) based on their
specific sensitivity to reference odourant n-butanol.
The odour concentration was determined by the
triangular forces choice method (ASTM E679-04).
Table 1: Concentration of swine odour with and without
PMAP for the 2 sets of the samples.
Sample
Odour
concen.
(OU/m
3
)
Reducing
(%)
S1- with PMAP 1413
S1- without PMAP 2825
50.0
S2- with PMAP 1072
S2- without PMAP 3235
66.9
In the tests with pig manure, two sets of samples
were taken from the two boxes for the olfactometer
analysis. For the first set, the odour samples were
taken from the two boxes after the swine manure
was sealed 18 hours, into two 10-L Tedlar bags
using a vacuum chamber (AC’SCENT Vacuum
chamber, St. Croix Sensory Inc., Stillwater, MN,
USA). When sampling, a bag was placed in the
chamber and the inlet of the bag was connected to a
Teflon probe which was inserted into one of the two
boxes through the hole on the box lid. Each sample
was taken in two steps: (i) fill the bag with 2 L of
odorous air and then evacuated to “coat” the bag,
and (ii) draw odorous air into the bag until the bag
was 75% full. Following the same sampling
procedure, the second set of samples was taken 8
hours after the first set of sample. Each set of sample
has two samples from the two boxes, respectively.
The H
2
S concentration was measured with a
Jerome Meter (JEROME 631-X Hydrogen Sulfide
Analyzer manufactured by Arizona Instruments) in
ppm with an accuracy of 0.001 ppm. After the two
A PLANT MATERIAL-BASED AIR PURIFICATION SYSTEM FOR SWINE ODOUR REDUCTION
121

boxes were sealed and the power of the PMAP
device was turned on, the experimental time was
started to count. Every 15 minutes the data were
taken from both boxes.
The ammonia (NH
3
) concentration was tested with
an ammonia detector tube produced by Gastec Inc.
with range from 0.5 to 50 ppm. A 0.1 ml NH
3
water
solution put in a small glass container as NH
3
source.
After two boxes were sealed and the power of
PMAP device was turned on for 3 hours an open end
of Ammonia detector tube was put into the 6 mm
hole in the lid of the boxes. The concentration data
were taken with a 100 ml pump.
3 RESULTS AND DISCUSSION
3.1 Reduction of Swine Odour
Table 1 shows results of swine ordour concentration
of two sets of the samples with and without PMAP
treatment after 18 and 26 hours for the first (S1) and
second set (S2) of sample. The odour in the control
box without PMAP treatment reached a very high
concentration of 2825 OU/m
3
in 18 h and 3235 in 26
h. These odour levels are much higher than what
normally exists in pig barns. In comparison, the
odour in box treated by PMAP was 1413 and 1072
OU/m
3
at 18 and 26 h, respectively. In other words,
the PMAP reduced the swine odour concentration by
50% at 18 h and 67% at 26 h. It is particularly
interesting to note that odour in the control box
increased from 2825 to 3235 OU/m
3
, or 15%, within
8 h; whereas, the odour in the treated box decreased
from 1413 to 1072 OU/m
3
, or -24% within 8 h. This
trend demonstrates that very high efficiency of
PMAP to reduce the swine odour.
It is also worth to note that the olfactometer
measures the odour concentration, not odour quality
(offensiveness). During the measurement, the
panellists noticed that the sample with the PMAP
treatment had a sweet smell, which was quite
different from the smell of the swine odour. This
means the odour concentration for the samples with
PMAP treatment included the scent of materials in
the PMAP itself. Therefore, the actually rate of
reducing swine odour might be higher than what was
measured by the olfactometer.
3.2 Reduction of H
2
S
Variations of H
2
S concentration from swine manure
in the two test boxes with time are shown in Figure
1. The concentration of H
2
S in the control box
without the PMAP quickly (30 minutes) reached the
maximum of 0.45 ppm, and then slowly decreased to
0.23 ppm in about 7 hours, while the concentration
of H
2
S in the box with the PMAP decreased sharply
from about 0.4 ppm to 0.02 ppm within 3 hours. The
reduction rate of H
2
S was about 95% within the 3
hours.
Figure 2 shows variation of H
2
S concentration from
the pure H
2
S source in the two boxes, again with and
without the PMAP, respectively. The H
2
S
concentration in the control box without the PMAP
quickly reaches the maximum, close to 24 ppm, and
Figure 1: Concentration of H2S for the pig manure source
with and without PMAP varies with time. The time starts
to be counted form the source sealed and the power of
PMAP device was turned on.
Figure 2: Concentration of H
2
S for pure H
2
S source with
and without PMAP varies with time. The time starts to be
counted form the source sealed and the power of PMAP
device was turned on.
then slowly decreases to 20 ppm in about 5.5 hours;
the concentration of H
2
S in the box with the PMAP
was sharply reduced and decreases to 3 ppm
(reduced by about 85%) within 3 hours and was
reduced to 0.2 ppm (a reduction of about 98%)
within 5.5 hours. Above two experiments, used pig
BIODEVICES 2011 - International Conference on Biomedical Electronics and Devices
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manure and pure H
2
S as odour sources, were more
than 2 replications.
The profiles of the curves in Figure 1 and Figure 2
are similar, which indicates that no matter if H
2
S is
from swine manure or from the chemical reaction,
the PMAP could remove it from the air efficiently.
The H
2
S is one of main gases in the swine odour
and it has been used as an odour indicator of swine
odour (Zhang at. el., 2003). The above result showed
that the H
2
S concentration decreased with time,
suggesting the mechanism of swine odour reduction
by the PMAP was by reducing its components, not
by “masking”.
3.3 PMAP Reduced Concentration of
NH
3
Table 2 listed the results of concentration of NH
3
in
the two boxes after 3 hours. For the pure ammonia
source, the NH
3
concentration in the control box
without the PMAP was 29 ppm (average of two
replications), whereas, the concentration of NH
3
in
the box with PMAP was near 0 ppm (both
replications) (table 2).
When pig manure was placed in the test boxes,
the NH
3
concentration with and without PMAP was
measured to be 38 and 10 ppm, respectively (table 2)
after 3 hours.
Table 2: Concentration of NH
3
measured with a NH
3
detector tube after PMAP power on for 3 hours.
NH
3
Source
Concentration of NH
3
With PMAP Without PMAP
Pure NH
3
29 ppm ~ 0 ppm
Swine
manure
38 ppm 10 ppm
It was noticed that the PMAP could not reduce the
NH
3
concentration to zero for the swine manure as
the NH
3
source. This was because of the swine
manure was continuously emitting NH
3
.
It is known that the high NH
3
levels in pig barns
decrease pig’s health and productivity (
Diekman et al.,
1993)
. Therefore, using the PMAP not only improves
the indoor air quality in pig barns but also has the
potential in improve pig’s health and productivity.
4 CONCLUSIONS
The laboratory experiment shows that the PMAP
consisting of a nano-crystalline plant extracts could
reduce the swine odour by at least 50%. The
measurement results also demonstrated that the
PMAP could reduce the concentrations of hydrogen
sulphide and ammonia
efficiently. This indicates that
the mechanism of PMAP to reduce the swine odour
was not masking. The PMAP provides a promising
approach to reduce the swine odour inside the pig
barns, thus improving the health of workers as well
as pigs.
Based on above results the future research has
first conducted field test to confirm the laboratory
results on PMAP material in pig barn. Secondly, It
will conduct further research to identify the active
components in PMAP to reduce the odour
efficiently. At last, the future research will
investigate the mechanism of the odour reduction by
PMAP.
REFERENCES
ASTM E679-04, 2004. Standard Practice for
Determination of Odor and Test Thresholds By a Forced
Choice Ascending Concentration Series Method of
Limits.
CEN. 2003. Air Quality-Determination of Odour
Concentration by Dynamic Olfactometry, EN 13725,
Technical Committee CEN/TC 264, European
Committee for Standardization.
DeBruyn, J. C. D. D. Mann, and Q. Zhang.
2001.Comparison of odour levels of biofiltered air and
ambient farmyard air. Canadian Biosystems
Engineering 43(6):7-11.
Diekman, M. A., A. B. scheidt, A.L. Sutton, M. L. Green,
J. A. Clapper, D. T. Kelly and W. G. Van Alstine, 1993.
Growth and productive performance, during exposure
to ammomia, of gilts affected with pneumonia and
atrophic rhinitis. Am. J. Vet. Res. 54 (12): 2128-31.
Donham, K., and D. Cumro. 1999. Synergistic health
effects of ammonia and dust exposure. p. 166. In Int.
Symp. on Dust Control in Animal Production Facilities.
Danish Inst. of Agric. Sci., Res. Centre Bygholm,
Horsens, Denmark
Gardner, J. W., H. W. Shin, and E. L. Hines. 2000. An
electronic nose system to diagnose illness. Sens.
Actuators B B70:19–24.
Grinshpun, S. A. A. Adhikari, T Honda, K. Y. Kim, M.
Toivola, K. S. R. Rao and T. Reponen, 2007. Control of
Aerosol Contaminants in indoor Air: Combining the
Particle Concentration Reduction with Microbial
Inactivation, Environ. Sci. Technol. Vol. 41, 606-612.
Heath. R. R. and A. Manukian, 1992. Development and
evaluation of systems to collect volatile semiochemicals
from insects and plants using a charcoal-infused
medium for air purification. J. Chem Ecology,
Vol.18:1209-1226.
A PLANT MATERIAL-BASED AIR PURIFICATION SYSTEM FOR SWINE ODOUR REDUCTION
123

Mann, D. D., J.C. DeBruyn and Q. Zhang. 2002. Design
and evaluation of an open biofilter for treatment of
odour from swine barns during sub-zero ambient
temperatures. Technical Note, Canadian Biosystems
Engineering 44:6.21-6.26 (Technical Note).
Phillips, M. 1992. Breath tests in medicine. Sci. Am. 267
(1): 74–79
Riley, R. L. and E. A. Nardell, 1989. Clearing the air. The
theory and application of ultraviolet air disinfection.
American Journal of Respiratory and Critical Care
Medicine [AM. REV. RESPIR. DIS.]. Vol. 139 : 1286-
1294.
Schiffman S. S. and Williams C. M. 2005. Science of
Odour as a Potential Health Issue, J. Environ. Qual.
Vol. 34, 129-138.
Vohra, A. D. Y. Goswami, D.A. Deshpande and S.S.
Block, 2006. Enhanced Photocatalytic Disinfection of
Indoor Air, Applied Catalysis B: Environmental Vol.
64, 57-65.
Wing. S. and Wolf. S. 2000. Intensive livestock
operations, health, and quality of life among eastern
North Carolina residents, Environ. Health Perspective,
Vol. 108(3) 233-238.
Zeng, H. Y, L. J. Jiang and Y. Q. Zhang. 2003. Chemical
constituents of volatile oil from Houttuynia Cordata
Thunb. J. Plant Resources and Enviroment, 3: 50-52.
Zhang, Q. and X. J. Zhou. 2003. Measurements of odour
and hydrogen sulfide emissions from swine barns.
Canadian Biosystems Engineering 45:6.13-6.18.
Zhao C. X., Y. Z. Liang, and X. N. Li, 2006. Chemical
Composition and Antimicrobail Activity of the Essential
Oil from Clove. Natural Product Research and
Development, 3: 381-385.
BIODEVICES 2011 - International Conference on Biomedical Electronics and Devices
124