Asian Journal of Atmospheric Environment
Vol. 7-2, pp.65-71, June 2013
doi: http://dx.doi.org/10.5572/ajae.2013.7.2.065

Diurnal and Nocturnal Behaviour of Airborne Cryptomeria
japonica Pollen Grains and the Allergenic Species in
Urban Atmosphere of Saitama, Japan
Qingyue Wang*, Shinichi Nakamura, Senlin Lu1), Daisuke Nakajima2), Miho suzuki,
Kazuhiko Sekiguchi and Makoto Miwa3)
Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura, Saitama, Saitama 338-8570, Japan
1)
School of Environmental and Chemical Engineering, Shanghai University, 99, Shangda Road, Baoshan, Shanghai 200444, China
2)
Resarch Center for Environmental Risk, National institute for environmental studies, Onogawa 16-2, Tsukuba, Ibaraki 305-8506, Japan
3)
Center for Environmental Science in Saitama, Kamitanadare 914, Kisai, Kitasaitama, Saitama 347-0115, Japan*Corresponding author. Tel: +81-48-858-3733, E-mail: seiyo@mail.saitama-u.ac.jp

ABSTRACTJapanese cedar (Cryptomeria japonica) pollinosis is
the most popular pollinosis in Japan. It has beenreported that Cryptomeria japonica pollen allergenic
species are suspended as fine particles in the urban
atmosphere. These allergenic fine particles are responsible for inducing asthma by breaking into thelower respiratory tract. It has also been found thatpollinosis symptoms on the sufferers appear mainly
at night-time by the results from epidemiologicalstudies. However, the exact reason for these phenomena is not yet clarified. In this study, the diurnal
and nocturnal behaviours of Cryptomeria japonica
pollen grains and their allergenic species in the urban
area of Saitama city of Kanto Plain were investigated.
Airborne pollen grains and allergenic Cry j 1 concentrations in total suspended particulate matter (TSP)
were investigated at two sampling sites, a heavy
traffic road (roadside site) and at the balcony of the10th floor of the Building of Research and Project ofSaitama University (general urban site). The lattersampling site where located about 300 m away fromthe roadside site was used as a general urban site
unaffected by automobile traffic. The airborne pollencounts were measured with a real-time pollen monitor. Cry j 1 particles were collected with two highvolume air samplers, and these concentrations were
measured by surface plasmon resonance methodwith a Biacore J system. The diurnal variation of theairborne pollen counts was similar to the trends oftemperature and wind speed during the day-time;
whereas its tendency with wind speed trend was notobserved during the night-time. Airborne pollencounts were lower with northern wind than withsouthern wind because the pollen comes from themountainous areas, and the mountains in the south

are closer, about half the distance to the northern
mountains. It is suggested that the peaks of airbornepollen counts during night-time in the sampling site
occurred by transport of pollen grains released during
day-time in the mountainous forest areas, located c.a.
100 km away from the sampling site. On the roadsidesite the allergenic Cry j 1 concentrations were higher
than at the general urban site, nevertheless pollen
grains counts were lower. These results suggested
that worsening of pollinosis symptoms during nighttime in urban area was caused by transport of pollen
grains during day-time in the mountainous forest
areas. Moreover, pollen allergenic species become
different morphology from pollen grain at roadsidesite, and the subsequent pollen grains re-suspension
by automobile traffic.
Key words: Cryptomeria japonica pollen, Diurnal
behaviour, Allergenic Cry j 1, Suspended particulatematters, Urban atmosphere

1. INTRODUCTION
Japanese cedar (Cryptomeria japonica) trees had
been afforested in mountainous areas from mid-1940s
to 1950s for post-war lumber demand in Japan (Okuda
et al., 2006). Currently, these trees have grown up over
30 years and heavily release pollen grains (Kitamura
et al., 2005). The prevalence of Japanese cedar pollinosis had become over 26.5% in Japan, especially it
had become higher than 30% in the urban areas in
Kanto (Murayama et al., 2010). The forest cannot beseen in urban areas of Kanto Plain, Japan. The airborne
Cryptomeria japonica pollen grains in the urban areas
are transported from the mountainous forest areas, several hundred kilometres away (Kanazashi and Suzuki,2010). Moreover, since pollinosis symptoms on the

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Asian Journal of Atmospheric Environment, Vol. 7(2), 65-71, 2013

sufferers are reported mainly at night-time (Maeda etal., 2008), it suggests that airborne pollen grains andallergenic species may be higher during night-time.
Cryptomeria japonica pollen has two main allergenic species, so-called Cry j 1 and Cry j 2, which areresponsible for pollinosis. These allergenic species
are located in the pollen wall and ubisch bodies onpollen surface and starch granules in the pollen grains,
Cry j 1 and Cry j 2 respectively (Nakamura et al., 2004).
Because of the high prevalence of pollinosis in urban
areas, air pollutants and automobile traffics are considered to produce synergetic effects on the allergens(Karle et al., 2012; Rogerieux et al., 2007; Behrendt
et al., 1997). Especially, symptoms of asthma on patients induced by Cryptomeria japonica pollen allergenic species have been observed (Maeda et al., 2008),
and worsening during pollen scattering season (Taylor
and Jonsson, 2004). It is suggested that this asthma iscaused by the breaking of small-sized Cryptomeria
japonica pollen allergenic species into lower respiratory tract. In contrast particle size of the pollen grains
is c.a. 30 μm, it had been reported that small-sized Cry
j 1 species were suspended as fine particles which particle size were below 1.1 μm in urban atmosphere(Wang et al., 2008). It is also thought that particles
containing small-sized allergenic species and pollen
grains deposited onto the paved asphalt road materials
are re-suspended by automobile traffic.
The behaviour of Cryptomeria japonica pollen grains
and of its allergenic species in the urban atmosphere(a)

has been studied in a few reports. It has also beenfound that pollinosis symptoms on the sufferers appear
mainly at night-time by the results from epidemiological studies. However, actual cause of these phenomena
is not yet clarified. Moreover, since allergenic particle
were collected over several days in these reports, diurnal behaviour of these allergenic particles was also
unknown. In this study, the diurnal behaviours of
Cryptomeria japonica pollen grains and their allergenic species in the urban of Saitama city of Kanto Plain,
Japan were investigated.

2. MATERIALS AND METHODS
2. 1 Location of Sampling Site
Monitoring of airborne pollen counts and the collection of particles containing allergenic Cry j 1 were performed in Saitama University, where is located in theurban area of Kanto Plain, Japan (35.86�
N and 139.61
�E) (site IV in Fig. 1(a)). The forests of Cryptomeria
japonica are around mountainous areas of Chichibu
and neighbour prefectures, several hundred kilometresaway from the sampling site. Most Cryptomeria japonica pollen grains in the sampling site were transported from those circumjacent mountainous areas. The
others observation sites in Fig. 1(a) observe pollencounts as part of monitoring network system of the
Ministry of the Environment (http://kafun.taiki.go.jp/;
22 Oct. 2012).

(b)

Fig. 1. Sampling location. (a) Site I: Forest Tree Breeding Station, Gunma; Site II: Gunma Prefectural Institute of Public Healthand Environmental Sciences, Gunma; Site III: Yorii town hall, Saitama and Site IV: Saitama city hall and Saitama University,
Saitama, Japan. (b) The sampling sites in Saitama University (S1: 2 m near roadside, S2: 300 m away from the roadside, the reddashed line indicates National road 463).

Nocturnal Behaviour of Pollen and Allergenic Species

The diurnal air samples were taken at two samplingsites in Saitama University (Fig. 1(b)). A roadside site(S1) where is located 2 m away from the vehicles passin the National Route 463, in Saitama University.
Another sampling site is settled in the balcony of the10th floor of the Building of Research and Project ofSaitama University (S2) (here after described as “general urban site”), about 300 m away from the roadsidesite (S1), as less effect site of automobile traffic. The
diurnal air samples were collected during 12-hours
sampling period (the day-time; 8:00-20:00 and thenight-time; 20:00-8:00) from 26 March to 8 April,
2011.

2. 2 Monitoring of Diurnal Airborne Pollen
CountsThe diurnal airborne pollen counts were monitored
and calculated with a real-time pollen monitor (Model
KH3000-01, Yamatronics Co., Ltd., Japan) operated
at a flow rate 4.1 L/min. The pollen monitor counts
particles which have characteristics of previously memorized optical scatter pattern of 28 to 35 μm of diameter and spherical shape, such as the pollen grains,using optical system by forward and side scatter witha laser diode (Seno et al., 2002). The pollen counts ofmonitor are well correlated with those of the Burkard
pollen sampler which is used as the standard pollen
sampler in European countries (Takahashi et al., 2001a).
The results of airborne pollen counts were converted
into 12-hours average counts of the pollen per 1.0 m3
volume (counts/m3).
2. 3 Investigation of Allergenic Cry j 1
Concentrations in Airborne Particles
High-volume air samplers (Model HV-1000R, Shibata Scientific Technology Co., Ltd., Japan) were used
to collect atmospheric particles. Total suspended particulate matter (TSP) including Cryptomeria japonica
pollen grains and their allergenic fine particles werecollected on quartz fibre filters (Tokyo Dylec Co., Ltd.,
Japan).
Allergenic Cry j 1 species were extracted using thefollowing method: A circular area with a diameter of
47 mm was cut from the quartz fibre filters, this area
was added 2 mL of Cry j 1 extraction solution (150 mM
of NaCl, 0.125 M of NH4CO3, 3 mM of EDTA, 0.005
wt% of Tween 20 and 10 mM of HEPES buffer solution) (Wang et al., 2010) and left overnight at 4�
C, andthen shook at 192 rpm for 1 hour. Afterwards the samples were centrifuged for 30 min at 6,000 rpm, and thesupernatant solutions were picked up. Finally, allergenic Cry j 1 concentrations on these supernatants were
measured by a Biacore J system (GE Healthcare Co.,
Ltd., Japan) based on the surface plasmon resonance67(SPR) method.
The SPR method was used to detect Cry j 1 concentrations by using allergen-specific monoclonal antibodies and the Biacore J system, as previously described (Wang et al., 2012; Takahashi et al., 2001b) withthe following minor modifications: Allergenic Cry j 1
concentrations in measured samples were determinedbased on Cry j 1 monoclonal antibody (MAb) (clone
013, Asahi Food & Healthcare Co., Ltd., Japan) immobilized on a CM5 sensor chip (GE Healthcare Co., Ltd.,
Japan) by using the SPR method with the Biacore J
system. Approximately 700 μg of Cry j 1 MAb wasimmobilized on the chip. The regeneration and dissociation of antigen-antibody complex reaction on theCM5 sensor chip were performed by 70 μL of pH 2.0
glycine-HCl (GE Healthcare Co., Ltd., Japan). Finally,
the results were converted into Cry j 1 concentration(ng/m3) in the urban atmosphere (Wang et al., 2012).

2. 4 Meteorological Data during the
Sampling Periods
Meteorological data were supplied from the Saitama
Institute of Public Health and the Okubo Purification
Plant which only located around 700 meters from our
air sampling sites. Data on precipitation, wind speed,
wind direction and temperature were acquired.

3. RESULTS AND DISCUSSION
3. 1 Diurnal and Nocturnal Behaviour of
the Airborne Pollen Grains
Fig. 2 indicates the diurnal and nocturnal variationsof meteorological data (temperature, precipitation(Fig. 2(a)), wind speeds and wind direction (Fig. 2(b))
and the airborne pollen counts and allergenic Cry j 1
concentrations at the roadside site and the generalurban site from 26 March to April 8 in 2011 (Fig. 2(c)).
In both sites, the highest airborne pollen counts were
764 counts/m3, and average pollen counts were 180
counts/m3. The highest airborne Cry j 1 concentrations
were 50 ng/m3, and average Cry j 1 concentrations
were 18 ng/m3 during the observation period. It has
been reported that the symptoms of pollinosis appear
when reaching a few pg/m3 of allergenic Cry j 1 concentrations in the atmosphere (Takahashi et al., 2001b).
Thus, the airborne Cry j 1 particles suspended above
the threshold level that triggers pollinosis symptoms
during the observation.
The diurnal variation of the airborne pollen counts
showed good correlation with temperature, and this isin good agreement with the report by other researchers(Bartkova-Scevkova, 2003). At the latter air sampling
period, the airborne pollen grain counts notably incr-

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Asian Journal of Atmospheric Environment, Vol. 7(2), 65-71, 2013

(a)

(b)

(c)

Fig. 2. Diurnal variation of temperature, precipitation (a), wind speed, wind direction (b), pollen counts and allergenic Cry j 1
concentrations (c) at the roadside site and the general urban site. Meteorological data were provided by the Saitama Institute of
Public Health and the Okubo Purification Plant.

eased with increasing temperature. It has reported thatpollinosis suffers are induced symptoms by temperature above 15�
C (Dejima et al., 1992). Therefore, it isthought that the airborne pollen grains are also increased by high temperature.
The trend of the airborne pollen grains was similar
to the trend of wind speed during day-time; whereas
this similarity was not observed during night-time. It
is thought that the airborne pollen counts were related

to wind speed, because under stronger winds more pollen grains are released from the source trees. During
night-time, it was also thought that only a few pollen
grains are released from the original trees of emission
sources, since male flowers which contain pollen grains
close under dark conditions.
During night-time in 30 March, the airborne pollen
grains and Cry j 1 concentrations decreased after 1 mmof rain precipitation. Airborne particles disappearedNocturnal Behaviour of Pollen and Allergenic Species

69

Table 1. Hourly data of wind direction during night-time of
2 Apr. and day-time of 7 Apr. at Saitama, Saitama.
At night-time of 2 Apr.

At day-time of 7 Apr.

Observation
time

Wind
direction

Observation
time

Wind
direction

20
21
22
23
24
1
2
3
4
5
6
7
8

NNW
N
NNW
NNW
NNW
NNW
NNW
NNW
NNW
NNW
NW
NNW
NNW

8
9
10
11
12
13
14
15
16
17
18
19
20

WNW
N
NNE
SW
SSW
S
SSE
S
S
S
S
SSW
S

from the atmosphere by trapping into rainwater, due
to the so-called wash-out phenomenon. The airbornepollen grains and particles containing allergenic Cry j
1 also disappeared by trapping into rainwater.
Airborne pollen counts were lower with northernwind than with southern wind. The mountains in thesouth are closer, about half the distance to the northern
mountains. Temperature also increased with southernwind. It is thought that pollen counts depend more on
temperature rather than on wind speed. On the other
hand, pollen counts are strongly affected by wind speed
when northern wind blows, because of the longer transportation distance.
The airborne pollen counts peaks were observed whenwinds blew mostly from northwest and southwest.
During the night-time of 2 April, wind direction insampling sites was kept northwest (Table 1). Observation sites of Maebashi and Yorii, near the site II andsite III in Fig. 1, where windward of sampling sites
were also kept northwest wind (Data not shown). Thus,
it was estimated that the airborne pollen grains weretransported from mountainous areas of Gunma prefecture located c.a. 100 km away from the sampling site.
At day-time of 7 April, winds blew from northwest till
10 a.m., subsequently southern wind blew till nighttime. Thus, it was estimated that the airborne pollen
grains were mostly transported from mountainous
areas to the west of Tokyo metropolitan area andlocated c.a. 50 km away from the sampling site.

3. 2 Airborne Pollen Counts Peaks during
the Night-time in Urban Areas of
Kanto Plain
Fig. 3 shows the tracking data of the airborne pollen
peaks at night-time of 2 April using monitoring network

Fig. 3. Time variation of airborne pollen counts at 2 April to
3 April in 2011. About 8 to 9 hour peak delays of airbornepollen counts were observed at site IV of the urban comparedwith the site I of original emission sources. Here, site I: Forest
Tree Breeding Station, Gunma; site II: Gunma Prefectural Institute of Public Health and Environmental Sciences, Gunma;site III: Yorii town hall and site IV: Saitama city hall, Japan;
Data were downloaded from the Ministry the of Environment(http://kafun.taiki.go.jp/; 22 Oct. 2012).

system of the Ministry of the Environment (http://
kafun.taiki.go.jp/; 22 Oct. 2012). Observation sites I,
II, III and IV are related to each observation site ofFig. 1(a).
The Forest Tree Breeding Station as the observationsite I is located nearest mountainous area of originalemission sources of pollen grains. The pollen peak
appeared at site I at the noon on 2 April were moving
to the southern observation site with decreasing pollencounts by diffusion, since wind blew from north atnight-time of 2 April. The pollen peak went throughto site II at 14:00, site III at 17:00 and site IV, where
located near our sampling sites, at 21:00 on 2 April.
Another pollen peak appeared in site I at 18:00 also
went through site IV at 2:00 on 3 April. The airbornepollen grains arriving to our urban sampling site need
8 to 9 hours, which is about 8 to 9 hour delay shownin Fig. 3 after being released from the Japanese cedar(Cryptomeria japonica) forest as the original emission
sources. Thus, the pollen grains from original emission
trees in the forest in the mountainous areas, released
during the day-time, were observed at our urban sampling site during the night-time. The transportation
times were consistent with the average wind speed, 2
m/s at the day-time of 2 April. As the result, it wasthought that appearance of peaks of the airborne pollencounts during the night-time in urban area of Kanto
Plain was produced by transportation of pollen grains
released from trees in mountainous areas during the
day-time.

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Asian Journal of Atmospheric Environment, Vol. 7(2), 65-71, 2013

(a)

(b)

Fig. 4. Correlation between the roadside site and the general urban site in (a) pollen counts and (b) allergenic Cry j 1 concentrations.

3. 3 Comparison between the Airborne
Pollen Counts and Allergenic Cry j 1
Concentrations
The correlations about pollen counts and allergenic
Cry j 1 concentrations between the roadside site andthe general urban site are shown in Fig. 4(a) and Fig.
4(b) respectively. Cry j 1 concentrations between theroadside site and the general urban site indicated similar behaviour in common with pollen counts. Cry j 1
concentrations at the roadside site were higher than at
the general urban site; whereas pollen counts werelower. Differences of these behaviours between daytime and night-time were not observed.
It is thought that the airborne pollen grains in thesky of urban areas keep their morphology, since theseairborne pollen grains are just transported from releasing forest sources in mountainous areas, and not affected by air pollutants and automobile traffic. In the urban
atmosphere, the airborne pollen grains underwent morphological change such as burst of pollen grains andadhesion of other suspended particulate matter (Okuyama et al., 2007), and small-sizing of particles containing allergenic Cry j 1 (Wang et al., 2008). We presume that pollen grains were more suspended on theroadside site, since there were more pollen grains transported and re-suspended. However, the results weredifferent from our thinking. For the results, it is suggested that morphological change of pollen grains including small-sizing is enhanced at roadside by heavy
traffic.
It may be thought that during the deposition processof transported pollen grains on the asphalt, their counts
would decrease by deposition on trees. However, theeffect of dry deposition was low, since Cry j 1 concentrations on the roadside site were higher than ones at
the general urban site. The results suggested that the

airborne pollen grains in the urban atmosphere include
morphological changed pollen grains were uncounted
by the pollen monitor device using optical systems
such as the monitor of KH-3000-01. This device iswidely used at the monitoring network system of the
Ministry of the Environment, Japan (http://kafun.taiki.
go.jp/; 22 Oct. 2012). It is possible that the real airbornepollen counts in urban atmosphere are underestimatedand this may lead to serious damages on pollinosis
sufferers.

4. CONCLUSIONSIn this study, it was investigated the diurnal andnocturnal behaviour of Cryptomeria japonica pollen
grains and its allergenic species in urban area in Kanto
Plain, Japan. Aims of this study were to gain knowledge
about the causation of worsening of pollinosis symptoms during night-time and formation of fine particles
containing allergenic Cry j 1 in urban area. Peaks ofpollen grains were observed during night-time in thesampling sites. Since the pollen counts were higher
than during the day-time in the peaks, it is suggested
that appearances of the pollen peaks during night-timein urban area are caused by transport and depositionof pollen grains. Allergenic Cry j 1 concentrations atroadside site were higher than ones at the general urban
site, nevertheless pollen grains counts were lower atroadside site. These results suggested that worseningof pollinosis symptoms during night-time in urban area
was caused by the transport of pollen grains during daytime from the original forest of mountainous areas.
Moreover, pollen allergenic species become different
morphology from pollen grain at roadside site, andthe subsequent pollen grains re-suspension by heavy

Nocturnal Behaviour of Pollen and Allergenic Species

automobile transportation.

ACKNOWLEDGEMENT
Some works of this study were supported by theSpecial Funds for Innovative Area Research (No.
20120015, FY2008~FY2012) and Grant-in-Aid for
Challenging Exploratory Research (No. 23651 005,
FY2011~FY2012) of Japanese Ministry of Education,
Culture, Sports, Science and Technology (MEXT),
Japan.

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(Received 10 January 2013, revised 21 March 2013,
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