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An important theme related to aerobiology is the spatial distribution of airborne pollen, which is a final goal of our research efforts. In relation to this, pursuing the severity of pollinosis symptoms and problems with airborne pollen and allergens is required. In the past, we simulated the distribution of airborne Japanese cedar (Cryptomeria japonica D. Don) pollen (Kawashima and Takahashi in Grana 34:142–150, 1995, Grana 38:316–324, 1999). The simulation results of recent years will be published in the near future. At the time, it was not possible to compare the results of actual airborne pollen data observed from multiple points at the same time. However, now we can achieve this objective if using C. japonica pollen characteristics. The pollen is dispersed in large quantities over a long distance, remains in the air for a long time, and most airborne pollen at this time is C. japonica pollen. Recently, several automatic C. japonica pollen monitoring systems have been developed and deployed nationwide. Pollen Robo is one and is the most widely installed nationwide. In this study, we addressed Pollen Robo. First, we examined whether Pollen Robo can accurately count C. japonica pollen and found that Pollen Robo was useful during the major pollen season. However, it sometimes counts non-pollen particles and other pollen rather than C. japonica pollen. Therefore, it is not useful when a small amount of pollen is dispersed such as the start day of the pollen season. Next, we examined the daily dispersion of C. japonica pollen and it was shown that it is related to the distance between sampling locations. However, factors other than distance may be involved. Another matter of concern is the relationship between the number of airborne pollen and pollinosis symptoms. Symptoms began to appear from approximately the start day of the pollen season in moderate and light cases. The most serious symptoms occurred when the pollen count was the highest. Meanwhile, in severe cases, symptoms were observed at the time the pollen was scarcely detected and plateaued when the pollen count reached 100 counts/m3 on average over 6 days. Thus, Pollen Robo was not useful when symptoms began in severe cases. This problem was solved using pollen antigen measurement. The time for the symptoms to begin in severe cases is between 2 and 4 weeks before the start day of the pollen season. The amount of Cry j 1 on the start day during some years was considerably larger than that calculated from the number of pollen. The results obtained in this study will be the basic data used for achieving our final goal.

Values obtained by the real-time pollen monitors set up at 14 measuring points in the Tohoku region indicate that a large amount of Japanese cedar pollen was dispersed along the western region and northern flank of the Ou Mountain Range when a front accompanying the temperate low pressures passed through the west sea of northern Hokkaido. We are sure that this phenomenon is related to pollen enrichment by mountain ranges. The time at which highest concentrations of pollen grains were observed shifted from the western to the eastern side, in accordance with the path of the front. No pollen was seen after the passage of the cold front.

We have developed a highly sensitive method for the measurement of airborne orchard grass (Dactylis glomerata: Dac g) pollen antigens using an electron spin resonance (ESR) radical immunoassay. In this immunoassay, the lowest detectable level of Dac g antigen in a sample is 0.1 arbitrary unit; the amount of Dac g antigen in single pollen grains was found to be as 1.84 units. Thus, Dac g antigens can be detected in amounts of 1/20th of that contained in the grain. This immunoassay enables early detection of grass pollen antigens. Such information may be useful for patients with grass pollinosis, especially for those who show symptoms when only low levels of the pollen antigens are present in air. In this study, minor amounts of Dac g antigen (cross-reactive antigens) were detected in late March, after which the levels gradually increased. The levels were detected to be 10 units/m3 until the middle of May and then increased after blooming of orchard grass. High levels were maintained until the middle of June. Some patients who suffer from grass pollinosis show symptoms in late April and early May, when the airborne Dac g antigen levels were found to be 5–10 units/m3.

In order to establish a real-timemeasurement system for the concentration ofairborne pollen allergens, we examined Cry j 1,one of the major allergens of Cryptomeriajaponica pollen, as an example to establishthe system. The feasible system consisted of:collection of airborne pollen allergens usingthe Virtual Impactor or Cyclone sampler,extraction of Cry j 1 using 10mM HEPES buffercontaining 0.125M NH4HCO3 andfinally, real-time measurement of Cry j 1 usingthe BIACORE 3000 system. The sensitivity of thesystem was 5 ng/ml, and 0.1 ml sample volumeand at least 500 pg of Cry j 1 were requiredfor each measurement. Quantification of Cry j 1in the air can be determined 30 min aftercollection, i.e. 15 min for extraction, 10 minfor separation from particulate matters and 5min for the measurement.

We examined the kinetics of airborne levels of mite allergen particles in a house by combined use of an indoor Burkard air sampler and immunoblotting. Airborne mite allergens collected on the Burkard sampling tape were transferred onto a nitrocellulose membrane, reacted with mouse monoclonal anti-mite allergen (Der pI) antibody, then treated with alkaline phosphatase conjugated anti-mouse IgG. Finally, the blotted allergen on the membrane was reacted with BCIP/NBT phosphatase, and purple spots visible by the naked eye were produced. The shape of the spots was observed under a microscope, and the spot area was measured by an image processor. This technique might be useful for analyzing the behavior of airborne allergen particles in indoor environments.