Pollen Monitoring in the City of Ivano-Frankivsk, Western Ukraine

The results of aeropalynological studies in Ivano-Frankivsk during 2013–2015 are presented in this article. The studies were conducted using a specially designed gravimetric Durham pollen trap installed at a height of 24 m from the ground. We determined that pollen grains of the following taxa dominate in the city’s aeropalynological spectrum: Corylus, Alnus, Betula, Populus, Fraxinus, Salix, Carpinus, Quercus, Pinus, Picea, Poaceae, Urticaceae, Artemisia, and Ambrosia. Pollen grains from woody plants dominate the aeropalynological spectrum. The considerable presence of the tree pollen grains in the ambient air is due to the geographical location of Ivano-Frankivsk in the forest-steppe zone of Ukraine. Pollen season of allergenic plants lasts from the second week of February to early October. The most unfavorable period for patients with pollen allergy in Ivano-Frankivsk is April, when there is a simultaneous appearance of high concentrations airborne allergenic pollen of Betula, Fraxinus, and Carpinus. From the second week of May to mid-July, high (>50 pollen grains/m3) concentrations of allergenic pollen of the Poaceae family members are detected in the air. In the second half of August and early September, high concentrations of allergenic Ambrosia pollen were recorded in the city air. Conducting of pollen monitoring in the city is extremely necessary for prevention, diagnosis, and treatment of pollen allergy.


Introduction
Pollen is a major component of biological air pollution. Inhalant allergic diseases are caused due to the presence of such allergens in the air. In various regions of Ukraine, pollinosis affects 20%-30% of the population (Pukhlyk, 2011). Therefore, the data on the quantitative dynamics of allergenic pollen in a particular area form the basis for assessing and predicting the aero-allergenic situation. The concentration, species composition, and regularity of migration of allergenic pollen are closely related to the climate, relief, extent, and the anthropogenic activity in a particular region. Therefore, to establish the regional uniqueness of the palynological spectrum of allergenic plants, aerobiological monitoring should be conducted.
Currently, there is a widely coordinated network of stations in Europe that monitors pollen concentrations of several allergenic plants. Old approaches were inadequate compared to those available today. Spectrum determination of allergenic plants, methods for collecting and processing pollen grains, and researching the allergenic properties of the pollen are being increasingly focused upon, and new approaches to realize the same, such as color electronic atlases, pollen calendars and seasonal pollen distribution maps of various taxa, are being developed (Jäger, 2013).

Material and Methods
Surveys were conducted during 2013-2015 in Ivano-Frankivsk City (geographical coordinates: 48 • 55 ′ N, 24 • 42 ′ E, at an altitude of 260 m). The city is located on the Pokut plain in the southwest of Ukraine between the Bystritsa Nadvirnyanska and Bystritsa Solotvynska. The climate of Ivano-Frankivsk is temperate continental. The average temperature in July is 17−19 • С and −5 • C in January. The average humidity is 68%-70%, and the average annual rainfall is 600-700 mm. From a landscape perspective, the city is considered an urbanized territorial complex. This is a part of the natural landscape heavily transformed by buildings, communication infrastructures, and other urban elements. The primary air pollutant in the urban ecosystem of Ivano-Frankivsk is road transport, which accounts for 83% of the total pollution of atmospheric air. The potential natural vegetation of the Ivano-Frankivsk region can be defined as the deciduous forest community type. There are several large park zones with remnants of natural vegetation within the city, and a mosaic of forests and farmlands forms the environs of Ivano-Frankivsk.
The gravimetric method was used for pollen collection using a Durham's dust trap that was installed at a height of 24 m from the ground (Figure 2). Glycerinlubricated slides were replaced daily from early February to mid-October. The pollen grains were counted using an Olympus CX-300 light microscope (×400 magnification) by continuous vertical transects (the analyzed area of the glass comprised 11.52 cm 2 ). A special factor was used for calculations to compare the data obtained by gravimetry to those obtained using the volumetric method. Pollen concentration was expressed as the daily average number of pollen grains in 1 m 3 of air per 24 hr (Bassett et al., 1978). Monitoring was conducted from the beginning of February to the middle of October, in 2013, 2014, and 2015. Pollen grains were delegated to the taxonomic unit "genus" and in some cases "families" (such as Urticaceae, Chenopodiaceae, and Poaceae). Damaged and unidentified pollen grains were classified as "other. " All calculations and graphical interpretations of the study results were conducted using MS Excel (2010).
The Ambrosia pollen season started in the third week of July. The highest concentrations were observed in the second week of August 2013, in the first week of September 2014, and in the third week of August 2015. The end of the season was observed in the third week of September ( Figure 6).

Discussion
The list of major taxa that formed the city's pollen spectrum during 2013-2015 remained unchanged, but the pollen share of individual taxa varied greatly. Thus, in 2013 the share of Piceae genus comprised 20%, in 2014 it was lower than 1%, and in 2015 it was 6.7%. In 2013, the share of Carpinus pollen varied greatly. In 2014, single pollen grains of Carpinus were recorded in the air of the city of Ivano-Frankivsk, which comprised 0.2% of the annual pollen spectrum, and in 2015, their share was 10.8%. This is explained by the endogenous plant features. The alternation of vegetative and reproductive phases in various plants has been described in literature (e.g., Severova, 2004). The production and release of large amounts of pollen require the expenditure of copious amounts of energy on the development of plant vegetative/generative organs; therefore, inflorescence development reduces in the following year. Hence, the year with high pollen concentration comes after the year with low pollen content. According to the literature, many temperate zone woody plants are characterized by periodic alternation of "productive" and "unproductive" seasons. The 2-year pollen production cycle was described for Betula by Severova (2004).
Unlike the city of Ivano-Frankivsk, in the south of Ukraine (Zaporizhzhya City), the main component of the annual airborne pollen spectrum is grass pollen dominated by allergenic ragweed pollen. The results of the studies conducted in Zaporizhzhya (Prikhod ′ ko, 2006(Prikhod ′ ko, , 2008 indicate that the Ambrosia pollen dominates in the air with the percentage share of 45%, whereas in Ivano-Frankivsk, it was maximum at 2.8%. The presence of pollen from the Corylus and Alnus plants in the air of Ivano-Frankivsk in February is consistent with the results of aeropalynological studies in Poland (Sosnówka and Cracow) (Myszkowska, 2013) and in Lviv (Kalinovych et al., 2016).
The beginning and the end of pollen release in individuals of the Poaceae family in Ivano-Frankivsk coincided with those in Lviv, but the maximum concentrations were 5-6 times higher (Voloshchuk, 2014).
The pollen season of the Ambrosia plants in Ivano-Frankivsk and Lviv coincided, but pollen concentrations were higher (maximum 183 pollen grains/m 3 in Ivano-Frankivsk, and in Lviv in different years of the study did not exceed 12 pollen grains/m 3 ) (Voloshchuk, 2014). Instead, in the southern and eastern cities of Ukraine, the contribution of pollen grains of Ambrosia to the airborne pollen spectrum was over 50%. The maximum pollen concentrations of this plant in Dnipropetrivsk was 1,491 pollen grains/m 3 (Rodinkova, 2013a), and in Zaporizhzhya it was 1,950 pollen grains/m 3 (Maleeva & Prikhod ′ ko, 2016).

Conclusions
The aeropalynological monitoring results in Ivano-Frankivsk City indicate that there are two pronounced pollen concentration peaks. The first wave occurs in the spring and is attributed to the more intense pollen season of the tree species, while the second wave occurs in the summer-fall, and is attributed to herbaceous plants.
In 2013 and 2015, the ratio tree pollen vs. herbaceous pollen was similar (in 2013 -76:24 and in 2015 -67:33). The high occurrence of the tree pollen grains in the ambient air of Ivano-Frankivsk City is due to its geographical location in the foreststeppe zone of Ukraine.
Pollen release of allergenic plants continued from the second week of February until the beginning of October. From an allergological perspective, in Ivano-Frankivsk April is the most unfavorable period, when high concentrations of allergenic pollen of Betula, Fraxinus, and Carpinus were observed. Among the herbs, the highest concentrations were recorded for Poaceae. High pollen concentrations occurred from the second decade of May to mid-July, except for days with high air humidity and precipitation. In the second half of August and early September, high concentrations of allergenic pollen of the Ambrosia were recorded. The pollen of the above-mentioned herbaceous plants is characterized by a high allergenic potential and create a risk of pollinosis among susceptible population groups. Therefore, it is necessary to monitor the airborne pollen concentrations and carry out forecasts considering meteorological factors and regularities of allergenic plant flowering. It is extremely important for Ukraine to create a national aeropalynological monitoring network, with further inclusion of observation points with the EAN. It will significantly supplement and increase the informational content of the latter and will create favorable conditions for further developments in this scientific field in Ukraine.