55

Japanese Cedar Airborne Pollen Monitoring by Durham’s andBurkard Samplers in Japan ―Estimation of the Usefulness of
Durham’s Sampler on Japanese Cedar Pollinosis―
Reiko KISHIKAWA1*, Norio SAHASHI2, Akemi SAITOH3, Eiko KOTOH4,
Teruhumi SHIMODA1, Shunsuke SHOJI5,
Kazuo AKIYAMA3 and Sankei NISHIMA1,41National Hospital Organization Fukuoka Hospital, Fukuoka, Japan2
Toho University, Chiba, Japan
3
National Hospital Organization Sagamihara Hospital, Yokohama, Japan
4
Japan Allergy Foundation Kyushu Branch, Fukuoka, Japan
5
National Hospital Organization Tokyo Hospital, Tokyo, Japan*e-mail: kishi@mfukuoka2.hosp.go.jp

Abstract
An attempt was made to compare pollen counts determined by the volumetric method (Burkard
sampler) with the gravitational method (Durham’s sampler) during the flowering seasons of evergreen
coniferous trees such as (1) Japanese cedar, Cryptomeria japonica (abbreviation in this article: JC) and (2)Cupressaceae family, mainly hinoki cypress, Chamaecyparis obtusa (abbreviation: Cup). Observations
were carried out in the cities of Fukuoka, Sagamihara and Funabashi over five consecutive years. The pollencounts obtained by Durham’s method correlated very well to the counts obtained by the Burkard technique.
Intensity of airborne pollen dispersion varied regionally and from year to year. Very low pollen counts wereobserved in Fukuoka in 2004 and excessively high pollen counts in Sagamihara in 2005.
Comparison of the results derived from Durham’s sampling method with those derived from Burkard’s
sampling method revealed that these two methods are equally suitable for monitoring exposure to airborne
JC and Cup pollen. To determine the starting days of JC and Cup pollen dispersion, Durham’s technique is
not inferior to Burkard’s technique, but rather defines the start of pollen dispersion more distinctly. A
long-term record of pollen counts obtained by Durham’s technique from 1986 to 2008 in Fukuoka, revealed
that the predictive values showed very low pollen counts in the case of particularly low July temperatures inthe year before. As a conclusion, continuation of airborne pollen monitoring by the volumetric method(Burkard’s sampling technique) in comparison with the gravitational method (Durham’s sampling technique) will be required to evaluate the validity of the two methods for the climatic conditions of Japan. On
the other hand, potential advantages of pollen data obtained by Durham’s sampler deserve international
re-evaluation.
Key words: Burkard’s sampler, Cryptomeria japonica, Chamaecyparis obtusa, Durham’s sampler,pollen monitoring, pollinosis

1. Introduction
Planting of Japanese cedar, Cryptomeria japonica D.
Don (sugi in Japanese, abbreviated to JC in this article)
trees was promoted throughout broad areas of Japan(Yokohama & Kanazashi, 1990). It prevails as the main
harvest timber on the Japanese islands except Okinawa
and most of Hokkaido. On the other hand, planting oftrees of the Cupressaceae family, mainly hinoki cypress,
Chamaecyparis obtusa (hinoki in Japanese, abbreviatedGlobal Environmental Research
13/2009: 55-62
printed in Japan

to Cup in this article) has been less extensive, prevailingfrom Fukushima Prefecture in the north to the westernpart of Honshu and in the several parts of Shikoku andKyushu islands.
Systematic forestation with coniferous trees began in
the middle of the Meji Era (at the end of the 19th century) and the extent of coniferous woodlands has increased since that time. Forestation was promoted evenfurther after World War II with continuous support fromthe Japanese government, which provided supplies©2009 AIRIES

56

R. KISHIKAWA et al.

to improve Japan’s forest resources. The total areaof JC forestation’s in particular, has increased to
4,510,000 hectares (ha) in 1986, i.e., to about twice thearea forested in 1956.
Because, the flowering and seed bearing of JC starts
about 30 years after planting, the production of JC pollen is generally proportional to the area of JC forests
exceeding an age of 31 years. Artificial JC forests older
than 31 years occupied 610,000 ha in 1970, 730,000 ha
in 1980 and 1.26 million ha in 1986. Considering theallergenic potency of JC pollen, the almost two-foldincrease in area of JC forests capable of dispersing pollen means that an increasing fraction of the Japanese
population is becoming exposed (Yokoyama &Kanazashi, 1990).
In the majority of JC forests, wild trees were planted
and, consequently, there is remarkable regional genetic
variation. Moreover, male flower formation and dispersal of pollen depend on weather conditions and geographic features. Accordingly, the amount of pollen in
the air to which humans are exposed is strongly regional.
Furthermore, pollen production of JC forests varies
markedly from year to year, and so does the exposure of
the population to airborne pollen.
In Japan the prevalence of AR (allergic rhinitis
and/or rhino-conjunctivitis) began to increase in the late1960s, growing more rapidly in the 1970s, with JC
pollinosis as a major causative factor. In 1998 the general prevalence of JC pollinosis was 16% (2,800/17,000),with regional differences due to the reasons mentioned
above (Committee of PG-MARJ, 2005).
Subjects susceptible to Cryptomeria pollinosis often
exhibit cross allergenicity to Cupressacea pollens. For
this reason, Cup pollen has to be considered as an allergenic antigen causing pollinosis. It is important to notethat the pollination season of Cup generally starts later
than the pollination season of JC. Therefore, the start of
exposure to airborne Cup pollen usually overlaps every
year with the exposure to JC pollen late in the season of
JC flowering. As the consequence, pollinosis caused by
JC flowering may be worsened and prolonged by subsequent Cup flowering. Similar to JC pollination, the startand intensity of Cup pollination fluctuate annually andare affected by climatic and geographical conditions
similarly to JC pollination.
Because JC generally flowers first, it is of particularclinical importance to monitor its onset as the point oftime at which exposure to airborne conifer pollens becomes relevant to susceptible humans as the beginningof the pollinosis season. JC pollen grains can be recognized by a finger-like projection (papilla) which isslightly bent at the top on the distal face and by theappearance of its intine layer (inner layer) in optical sections. These morphological properties clearly distinguish JC pollen grains from Cupressacea pollen grains.
The external morphology of Cup pollen grains differs only slightly between different Cup species or evengenera. Therefore, it would be difficult to distinguishbetween pollen grains of various Cup species and thoseof Chamaecyparis obtusa. However, pollen of the latteras the most widely distributed species prevails and isclinically most relevant as the cause of pollinosis.
Therefore, we did not distinguish among species whencounting Cup pollen. As mentioned above, airborne pollen from Chamaecyparis obtusa is clinically relevant
mainly as an agent prolonging or aggravating pollinosis
started by JC pollen. For this reason, the first appearance of Cup pollen in general is sufficient to indicate thestart of its airborne dispersion, and it is more importantfor surveillance of susceptible patients to monitor theintensity and duration of exposure to airborne Cup pollen after the start of Cup flowering.

2. AimThe authors used two methods to estimate density ofairborne pollen grains during the flowering seasons ofJC and Cup: a) the gravitational method according toDurham which is frequently used for pollen monitoringin Japan and b) the volumetric method according to
Burkard which prevails internationally as a standard
method. Standardized devices (Durham’s sampler,
Burkhard sampler) were available for pollen monitoring.
The authors’ aim was to compare the usefulness of thetwo methods by using them simultaneously in Japan.
For this purpose, airborne pollen grains were sampled
in the cities of Fukuoka (A: 130°24´E 33°35´N),
Sagamihara (B: 139°23´E 35°34´N) and Funabashi(C: 139°59´E 35°41´N) for five consecutive years,
starting in 2002 or, respectively, in 2003, as shown in
Fig. 1.

3. Materials and Methods
3.1 Pollen monitoring by the gravitational method
This method of monitoring airborne pollen in Japan
has been used since the 1970s when JC pollinosis wasrecognized as an important allergic disease. We collected pollen adhering to vaseline coated glass slides
which were fixed in the Durham sampler and exchanged
every morning, as a rule. After staining the samples withsaturated basic fuchsine (Carberla’s stain) we identified
the pollen grains at 400x magnification and counted
them at 100x magnification.
For the Durham method, pollen counts were standardized by expressing them as the number of pollen
grains per cm2.
3.2 Pollen monitoring by the volumetric method
Burkard spore traps were located in each one of theselected cities on the rooftop of the involved institutebuilding. The principle of pollen grain trapping consistsof passing 10 liters of air per minute through the
Burkhard sampler in which the grains adhere to a collection drum which is prepared with adhesive Melinex®
tape. Counts are evaluated internationally by three different methods. One each was used at each of the sampling sites.
In Fukuoka City located on Kyushu island (130°24´E
33°35´N, Fig. 1), we have monitored atmospheric aller-

The Usefulness of Durham’s Sampler on JC Pollinosis

genic conifer pollen since 2003 by evaluation according to the Pan-American Aerobiology Association,
Standardized Protocols (PAAA protocols) following
their comprehensive guidelines for the operation of
Hirst-type suction, bioaerosol seven-day record samplers by Christine Rogers, Michael Mulilenberg andEstelle Levetin, Tulsa University, Oklahoma (Copyright2001 by The Pan American Aerobiology Association).
The drum which is prepared with adhesive Melinex®
tape in the device is exchanged once a week, during
which airborne pollen is collected. After seven days ofcollecting airborne pollen, the Melinex® tape, to which
the pollen grains have become attached in the device, is
cut in 48 mm sections corresponding to 24 hours (oneday) with a width of 14 mm. Melted glycerin jelly withsaturated basic fuchsine or gentiana violet is placed oneach tape section for staining and each is subsequently
mounted between a slide glass and a cover glass forcounting under the microscope. According to the PAAA
protocol counting technique, grains are counted along
a longitudinal traverse near the middle of the trace(0.23 cm2) at 400x magnification (Rogers & Mulilenberg,
2001).
In Sagamihara City, Kanagawa Prefecture, in thecentral part of Honshu Island (139°23´E 35°34´N,
Fig. 1), we have sampled pollen grains also during every
seven-day period since 2003. We count pollen grainsusing the routine monitoring methodology for airbornepollen which is recommended by the European representatives of the International Association for Aerobiology (IAA) and determines pollen density by counting
along three longitudinal bands “sweeps,” although aminor modification was introduced in 2002 (Saito et al.,2005). We switched from counting along three longitudinal bands to counting along two longitudinal traverse bands, one along the middle of tape and the second
one along a line 3 mm vertically distant from the middle.
Counting is done at 100x magnitude and the counted
area is 0.96 cm2 for each 24 hour section of the 48 mm
adhesive tape (Saito et al., 2005; Kishikawa et al.,2007).

C
B TokyoA

A : Fukuoka city (130°24´E 33°35´N)
B : Sagamihara city (139°26´E 35°36´N)
C : Funabashi city (139°59´E 35°41´N)

Fig. 1 Locations of observation points where JC pollen was
identified.

57

For pollen counting performed since 2002 in
Funabashi City, located on Honshu Island (139°59´E
35°41´N, Fig. 1) east of the Tokyo metropolitan area, we
determined the entire number of pollen grains on a pieceof adhesive tape corresponding to a quarter of the entire
24 hr Merinex® tape section, i.e., grains adhering to apiece 24 mm long by 7 mm wide cut from the 48 mm ×
14 mm tape section representing the particular day(1.68 cm2).
For the Burkard method, the pollen counts were converted to grains/m3 of air. Basic data were daily mean
concentration values.
3.3 Comparison of counting methods
Pollen counts in their respective dimension obtainedby the gravitational method (standardized as counts
per cm2) were compared with the counts obtained by thevolumetric method (standardized as counts per m3). The
results obtained by each of the two methods are compared for each sampling site in Fukuoka, Sagamihara
and Funabashi. For each site the counts obtained by thetwo methods were correlated and correlation coefficients were tested for significance using the student test
for the total pollen count per season and for daily pollencounts throughout the season of airborne pollen dispersion.
Determination of the starting day of pollen dispersion was based on the Durham’s sampling technique anddefined, according to the Palynological Society of Japan,
as the first day on which more than 1 grain/cm2/day issampled on two consecutive days. The end of airbornepollen exposure was defined as the first of three consecutive days during which no pollen grains aremonitored by Durham’s sampler. This is also coincidedwith the definition by the Japanese PalynologicalSociety.

4. Results
4.1 Comparison of total pollen counts using
Burkard and Durham sampling techniques
Table 1 shows the total pollen counts of JC and Cup
obtained by Burkard and Durham samplers in Fukuoka,
Sagamihara and Funabashi. The average pollen numbers
in each city were 3,391-11,886/m3/season (JC: Burkard)
and 1,419-7,585/cm2/season (JC: Durham) for JC pollen.
Cup pollen numbers, ranged from 1,628-8,950/m3/
season (Cup: Burkard) and from 716-2,904/cm2/season(Cup: Durham).
Year-to-year changes were marked. They were smallest in Funabashi (not exceeding a factor of 18) but could
be very large (exceeding factors of 30) in Fukuoka andSagamihara. Degrees of year-to-year variations weresimilar for JC and Cup pollen counts, and are similarly
apparent in the results obtained by the Burkard andDurham sampling techniques.
The highest quantities of pollen counts were found in
Sagamihara both for JC and Cup pollens. The high average obtained for Sagamihara strongly depends on the
counts in a particular year (2005). Statistical evaluation

58

R. KISHIKAWA et al.

does not confirm, however, that average pollen counts
for both JC and Cup were consistently higher in
Sagamihara than in Fukuoka or Funabashi. Thus, theexceptional counts found in Sagamihara in 2005 illustrate a particularly favorable year for flowering of bothJC and Cup male trees.
As far as the numerical values obtained by the
Burkard and Durham methods are concerned, the generally lower numbers obtained by the Durham method
would suggest a difference in sensitivity between thetwo methods. However, Table 2 shows that the Durham
and Burkard data obtained at each sampling site during
the five consecutive years (Table 1) were closely correlated for each pollen type. Correlation coefficients listed
in Table 2 are generally high (>0.9) and range between
0.917 and 0.998. All correlation coefficients are significant (<0.05 to <0.001) at each location. Thus, there is no
Table 1 Annual total pollen counts using Burkard and Durham’ssamplers obtained for five consecutive years in Fukuoka,
Sagamihara and Funabashi.

Fukuoka
2003
2004
2005
2006
2007
averageSD
Sagamihara
2003
2004
2005
2006
2007
averageSD
Funabashi
2002
2003
2004
2005
2006
average
SD

Japanese Cedar
Burkard Durham
5,104
1,709
543
113
8,033
2,289
4,421
1,385
7,769
1,601
5,174
1,419
3,038
803

Cupressaceae
Burkard Durham
9,386
3,345
288
74
26,068
4,866
7,588
2,950
1,419
652
8,950
2,377
10,330
1,984Japanese Cedar
Burkard Durham
7,715
8,214
1,259
705
42,34522,832
2,660
2,074
5,451
4,100
11,886
7,585
17,2098,982

Cupressaceae
Burkard Durham
2,342
983
1,515
163
30,545
11,525
985
558
2,024
1,293
7,482
2,904
12,903
4,838

Japanese Cedar
Burkard Durham
4,231
3,498
2,411
1,771
1,297
336
7,069
5,872
1,947
786
3,391
2,453
2,327
2,264

Cupressaceae
Burkard Durham
2,157
866
1,922
409
463
157
3,404
2,038
196
112
1,628
716
1,316
797

Table 2 Correlation between total pollen counts obtained by the
Durham and the Burkhard pollen sampling techniques
during five consecutive years for JC pollen and Cup
pollen in Fukuoka, Sagamihara and Funabashi.

Fukuoka
Sagamihara
Funabashir (JC)pr (Cup)

p

0.923
0.984
0.994

0.025
0.00250.0005

0.917
0.998
0.918

0.02820.00010.0277counting
technique
PAAA
IAA (modified)Directindication of differences in reliability between the
different counting methods used for evaluation of the
Burkard sampling technique in the three cities, and withregard to total pollen counts, the two different pollen
sampling techniques (Durham and Burkard) seem to beequivalent.
4.2 Onset of pollen dispersion – Comparison of
Burkard and Durham sampling techniques
The onset of pollinosis due to pollen from coniferous
trees depends on the start of dispersion of pollen fromJC as the conifer usually starts flowering first after
winter. To elucidate the start of JC pollen dispersion wemonitored pollen counts daily using Durham’s andBurkhard’s sampling techniques simultaneously startingon January 1st. Studies were done for the same fiveconsecutive years (2003 to 2007) in Fukuoka andSagamihara. The most important problem from theclinical point of view was to determine the starting dayof pollen dispersion based on the Durham samplingtechnique, as explained above.
For Fukuoka City, Fig. 2 shows that the starting dayof JC pollen dispersion is quite distinctly definable
every year. Further, pollen counts obtained by Durham
and Burkard sampling coincide quite well. The correlation coefficients between the two methods were highly
significant (p<0.001) for the annual pollen counts in
2003, 2005, 2006 and 2007. In 2004, the levels of airborne pollen dispersion were unusually low and, consequently, the correlation coefficient of the counts
obtained by Durham and Burkard sampling was low, but
still significant (p<0.05) for the combined JC and Cup
pollen counts.
For Sagamihara City, Fig. 3 shows that the start ofJC pollen dispersion was more difficult to determine.
The Burkard sampling technique, in particular, provided
counts from the beginning of the observation period
during phases in which no or sub-threshold counts wereobtained by the Durham technique. Nevertheless, thecorrelation coefficients for the results obtained by the
Durham and Burkard counting techniques were high in
2003, 2006 and 2007 and significant (p<0.001). In 2004,
pollen counts were at low levels, although not as low as
in Fukuoka, and Durham and Burkard pollen counts
were significantly correlated (p<0.01). In contrast, in2005 the quantities of both JC and Cup pollen were
exceptionally large in Sagamihara as documented inTable 1. Further, JC pollen dispersion started unusually
early in that year on January 3rd as defined by Durhamcounting, and was already present on January 1st whencounting by the Burkard technique, so we did not evaluate them in 2005.

The Usefulness of Durham’s Sampler on JC Pollinosis
100

100
2003Durham JC
2003Burkard JC

10
1
January

pollen counts

pollen counts

1000

2006Dur JC
Bur JC
2006Burk
JC
1
January

February

0.1
1

5

9

13 17 21 25 29 33 37

1 4

100

7 10 13 16 19 22 25 28 31 34 37 40

100

10

2004D ur J C
2004Bur J C
1

Januarypoolen counts

pollen counts

10

February

0.1

10
2007D ur JC
2 0 0 7 BBuru rkJCJC
1
January

February

February

0.1

0 .1

1

5

1

9 13 17 21 25 29 33 37 41 45 49

47

10 13 16 19 22 25 28 31 34 37

Days fromfromJan.
Jan.1
Days
1st
st

100

pollen counts

59

10
2 0 0 5 D u r JC
2 0 0 5 B u r JC
1

January

February

0 .1
1

5

Year

start day

r

ｐ

2003

Feb 7th0.55

0.00042004

Feb 19th

0.29

0.04082005

Feb 19th

0.49

0.00032006

Feb 1st0.87<0.00012007

Feb 5th0.62

0.0003

9 13 17 21 25 29 33 37 41 45 49 53

Fig. 2 Start of JC pollen dispersion during the five consecutive years in Fukuoka from 2003 to 2007, using
gravitational (Dur) and volumetric (Bur) methods in parallel. The inserted table lists the starting day of airborne JC pollen dispersion.

pollen counts

1000
100
2003Dur JC
2003Bur JC

10
1
January

0.1
1

5

9

January

February

February

13 17 21 25 29 33 37 41

pollen counts

100

10
2004Dur JC
2004Bur JC

1
January

February

0.1

0.1
1

5

9 13 17 21 25 29 33 37 41 45 49stDaysfrom
fromJan.
Jan.1
Days
1st

pollen counts

100

10
2005Dur JC
2005Bur JC

1
January

February

Year
2003
2004
2005
2006
2007

start dayFeb.7thFeb.14th
Jan.3rdFeb.10th
Jan.31st

r
0.69
0.4
ND
0.53
0.93

ｐ
<0.0001
0.0063ND
0.0004<0.00010
1

4

7

10 13 16 19 22 25 28 31 34 37

ND：Not Done

Fig. 3 Start of JC pollen dispersion during the five consecutive years in Sagamihara from 2003 to 2007, using
gravitational (Dur) and volumetric (Bur) methods in parallel. The inserted table lists the starting day of
airborne JC pollen dispersion.

60

R. KISHIKAWA et al.

4.3 Summary of parameters of clinical relevance forconifer pollinosis
In Fukuoka, the following evidence was found.
Every Saturday, Sunday and holiday we collected pollen
automatically using Durham’s sampler prepared on the
day before and the Burkard sampler, with records every
seven days. Pollen counts obtained by each method
were arranged and examined: In Fukuoka, the correlation between Burkard daily pollen counts and Durham’s
data was high and highly significant for both JC and
Cup pollen counts from the start to the end of the pollen
dispersion periods in 2003, 2005, 2006 and 2007. An
exception was the pollen counts obtained in 2004,
because of unusually low levels of airborne pollen.
In Sagamihara, the following facts were observed.
Every Saturday and Sunday we collected daily pollen
samples automatically using an automatic four-day
modified Durham’s sampler and, in parallel, pollen wascollected using a Burkard sampler. Correlation between
the Burkard daily pollen counts and Durham’s data wasalways high and highly significant for both JC and Cup
pollen counts from the start to the end of the pollen
dispersion period in Sagamihara during each of the five
years from 2003 to 2007.
Shown are the start and end of pollen dispersion foreach year and each conifer type and the number of days
with supra-threshold airborne pollen levels. In addition,
the correlation coefficients between the annual pollencounts obtained by the Durham and Burkard method andtheir levels of significance are presented. Correlation
coefficients and significance levels were generally high,except for JC pollen in Fukuoka in 2004, because ofvery low levels of airborne pollen collected throughout
the flowering season in this area (also see Table 1).
Definitions of the start and end of pollen dispersion are
based on the counts obtained by the Durham method as
explained above.
In Table 3, the starting and final days of airbornepollen dispersion, as defined by the counts obtained by
the Durham method, and the number of days withsupra-threshold pollen density are presented for thetowns of Fukuoka and Sagamihara for the five consecutive years from 2003 to 2007. The start and end of
dispersion of both JC and Cup pollen are presented
separately. It is obvious that the flowering season of JC
consistently starts earlier than flowering of Cup and that
the Cup flowering period overlaps with the JC flowering
period. For patients who suffer from JC pollinosis andwho are susceptible to Cup pollen, it means a prolonged
period of allergenic exposure. The parameters summarized in Table 3 are useful from the clinical point ofview, because they provide information on when and forwhat duration preventive measures should be taken for
persons susceptible to conifer pollinosis in order toavoid or to mitigate conifer pollen allergies (Kishikawa
et al., 2004a, 2004b).
As additional information, Table 3 shows that theresults obtained by the Durham and Burkard counting
techniques are highly correlated in general for both JC
and Cup pollen counts. The single exception was theyear 2004 in Fukuoka, which stands out for the very
low pollen counts found for JC as indicated before in
Table 1.

Table 3 Seasons of JC and Cup pollen dispersion determined for Fukuoka and Sagamihara
during five consecutive years (2003 – 2007).

The Usefulness of Durham’s Sampler on JC Pollinosis

5. Discussion
Before World War II, Japanese people had little
conception on the occurrence of hay fever (pollinosis).
Since the 1960s increasing numbers of patients havebeen reported suffering from hay fever due to ragweed,
grass, Japanese hops, mugwort and occupational pollen
allergies. Hypersensitivity to JC pollen was recognized
first as an allergic disease peculiar to the Nikko area,
near Tokyo, and reported as a cause of pollinosis in
1963 by Saitoh & Horiguchi (1964). Thereafter,
increasing numbers of patients suffering from JC
pollinosis have been identified since the 1980s and it isrecognized as an increasingly serious nationwide social
problem which requires countermeasures to be taken by
the Japanese government.
Since the late 1980s the Japanese government has
initiated studies with the aim of making provisions forpreventing or mitigating the occurrence of JC pollinosis
in the Japanese population. As a successful approach tothe problem we have investigated airborne pollen
dispersion by monitoring its start, intensity and duration.
Gravitational sampling by Durham’s sampler as a technically simple method used already by our predecessors
was immediately available and easily applicable byclinicians, who have had little knowledge, so far, on
aerobiology. For this reason the gravitational method
using Durham’s sampler has become the most popularmonitoring technique used in Japan. Currently, we haveabout 400 JC pollen monitoring sites in our country.
The relationship is apparent between unusually low
annual pollen counts and low July temperatures of thepreceding year. Several meteorological parameters during July of the preceding year and total annual counts ofJC pollen and combined JC+Cup pollen counts during
the subsequent years are correlated, as given in thetables, showing correlation coefficients and statisticallyreliable levels of significance.
Figure 4 documents the predictive value of thisrelationship in providing information for clinicians℃

61

about the severity of seasonal pollinosis in the following
year and, thus, helping to make provisions for prevention and treatment. Data gathered by monitoring airborne pollen dispersion have also been shown to be
useful as short-term information about the onset, intensity and duration of potential exposures to JC and Cup
pollen for persons that may become afflicted by JC and
Cup pollinosis. Based on these data we have distributedpollen information and medical recommendations forpatients susceptible to pollinosis. This information has
been broadcasted in Fukuoka City from from February
1st to April 15th every year since 1988 in collaboration
with the Fukuoka Prefecture Medical Association.
According to our own experience we consider pollen
data obtained by Durham’s sampling technique a reliable and predictive basis for transmitting medically useful information to persons in Japan who are susceptible
to JC pollinosis. Because its predictive value is well
documented in Japan, it is suggested that the gravitational method, which is widely used in Japan, should be
re-evaluated internationally.
More frequently used as an international standard
method has been the volumetric Burkard method using
Hirst-Type suction for bioaerosol sampling. In line withthe history of pollen monitoring outside of Japan, thevolumetric method has become the standard techniquein Europe and USA.
Reviewing the results of monitoring conifer pollen
dispersion using the gravitational and the volumetricmethods simultaneously in parallel in Fukuoka,
Sagamihara and Funabashi, we found that the dataobtained by each method were, in general, closely correlated. According to our comparative analysis of volumetric and gravitational sampling techniques, the dataobtained by each method are equally valid in the
climatic conditions of Japan. This result is encouraging
for further efforts to compare volumetric and gravitational methods in Japan on a nationwide basis. For thispurpose, the new volumetric method should be usednationwide and, if possible, in parallel with the gravitational method established in Japan.
At the international level (Kishikawa et al., 2004a,
2004b, 2007), it would also be desirable to compare
worldwide data obtained by the two methods used in thepresent study. Currently, however, in sufficient data are
available outside of Japan from parallel applications ofvolumetric and gravitational methods.

6. Perspectives and Conclusions

pollen counts
previous Julymean temperaturemean humidity
mean solar radiation

r(JC)
0.775
-0.7330.729

P<0.0001
0.00010.0001[°C] July mean temperaturer(Cup.)
0.691-0.8490.651

pr(JC+Cup.)
0.00050.756<0.0001-0.8530.00140.721

P<0.0001<0.0001
0.0002

Fig. 4 Long-term (1986-2008) monitoring of annual pollencounts by gravitational method. Diagram: Total annual
JC pollen counts (left hand abscissa and columns) andJuly temperature (right hand abscissa and solid line).

We intend to continue investigations, aiming at
improving the methods of monitoring the occurrence
and distribution of allergenic pollens to promote preventive and therapeutic measures enhancing the quality oflife of persons susceptible to airborne pollinosis. Adjusting pollen monitoring in Japan to international standards
will require more frequent application of the volumetricsampling technique in Japan. Applying the Burkard
sampling technique in parallel with the well-established

62

R. KISHIKAWA et al.

Durham’s sampling technique in Japan will reveal theadvantages or shortcomings of either method. International use of the gravitational method would be encouraged if potential advantages of Durham’s techniquein predicting exposure to airborne pollen could be
documented.
We also want to continue monitoring the remarkableannual fluctuations in airborne JC and Cup pollen andcompare them with recent annual changes in meteorological conditions in Japan to give the useful
information for human health and the medical care ofpatients with hypersensitivity to conifer pollen antigens.

Yokoyama, T. and T. Kanazashi (1990) Annual change in the areaof Japanese Cedar forests as a source of allergic pollen. In:
M. Muranaka, K. Taniguchi, ed, Immune - globulin E antibody
and environmental factors, Medical Tribune, Tokyo, 67-78. (inJapanese)Acknowledgement
We appreciate Professor E. Simon for his helpful
suggestions on presenting the relationship between
gravitational and volumetric methods of airborne pollen
monitoring and Japanese cedar pollinosis in Japan. We
thank Professor M. Iriki for his patience and support in
helping us this paper. We appreciate the helpful advice
for the design of the investigation by Drs. T.M. Horiuti,
Y. Kondo, A. Togawa, T. Ide, H. Yasueda, Y. Takahashi,
P.D. Jantzi, E.G. Brooks, and Professor R.M. Goldblum.
Moreover, we are grateful to Professor E. Levetin andProfessor J. Emberlin who provided important comparative information on aerobiology in Japan through theirlectures on monitoring of atmospheric pollen and occurrence of hay fever in the USA and Europe.

Reiko KISHIKAWA, MD

Terufumi SHIMODA, MD

NHO Fukuoka Hospital
Allegologist

NHO Fukuoka Hospital,
Department of Clinical Research,
Chief Allegologist

Norio SAHASHI, PhD

Shunsuke SHOJI, MD

Toho University , Faculty of
Science, Professor
Aerobiologist , Botanist

NHO Tokyo Hospital, Departmentof Clinical Research,
Chief Allegologist

References
Kishikawa, R., T. Horiuti, A. Togawa, et al. (2004a) Juniper
pollen monitoring by burkard sampler in Galveston, Texas USA
and Japanese Cedar pollen in Fukuoka Japan, Arerugi. 53:
582-588. (in Japanease)
Kishikawa, R., E. Kotoh, N. Sahashi, et al. (2004b) The relationship between the patients and the medication during conifer
pollen season, Fukuoka, Japan, The 6th Asia Pacific Congressof Allergology and Clinical Immunolgy, Tokyo, Japan, Internal
Proceedings, EX04C0161, MEDIMOND, Bologna, Italy,
155-158. (in English)
Kishikawa, R., A. Saitoh, E. Kotoh, et al. (2007) Pollen monitoring by Burkard Sampler (Hirst-Type Suction Bioaerosol
Sampler) in Fukuoka city and Sagamihara city, The 48th
Annual Meeting of Palynological Society of Japan, Kurashiki,Japan. (in Japanese)
Rogers, C. and M. Mulilenberg (2001) Pan-American Aerobiology Association, Standardized Protocols, Comprehensive
guidelines for The operation of Hirst-Type Suction Bioaerosol
Samplers, website. Rogers C., M. Mulilenberg, 2001. (inEnglish)Saito, Y. and S. Horiguchi (1964) Japanese Cedar pollinosis in
Nikko Japan. Arerugi, 13:16-18. (in Japanese)
Saito, A., R. Kishikawa, H. Yasueda, et al. (2005) Pollen monitoring by Burkard Samlpler and the counting techinique in
Sagamihara city and Fukuoka city, The 46th annual meeting of
Palynological Society of Japan, Chiba, Japan. (in Japanese)
Committee on Practical Guidelines for the Management ofAllergic Rhinitis in Japan: Epidemiology of Japanese Cedar
pollinosis in Japan, Practical Guidelines for the Managementof Allergic Rhinitis in Japan 2005, Life Science, Tokyo, 8-12.
(in Japanese)

Akemi SAITOH, PhD

Kazuo AKIYAMA, MD

NHO Sagamihara Hospital
Allergy Center Immunologist

NHO Sagamihara Hospital,
vice-President Allergy Center,
President and Allergologist

Eiko KOTOH, Technician

Sankei NISHIMA, MD

Japan Allergy Foundation
Kyushu Branch

NHO Fukuoka Hospital, President
Japan Allergy Foundation Kyushu
Branch, President Pediatrician andAllegologist(NHO: National Hospital Organization)(Received 11 February 2009, Accepted 12 May 2009)