Abstract Atmospheric precipitation removes the majority of biological and chemical pollutants from the lower parts of the troposphere. However, some studies infer increasing atmospheric pollen concentrations during precipitation events and/or thunderstorms, which are known to trigger allergic reactions (referred to as thunderstorm-triggered asthma). The aim of this study was to determine the impacts of precipitation on the diurnal variability of airborne pollen concentrations, with particular focus on the timing and intensity of precipitation events. We also considered the impacts of other meteorological elements on atmospheric pollen concentrations. The research was conducted in Rzeszow (SE Poland) from 2016 to 2018. We used two aerobiological and two meteorological stations in this study to determine potential spatial variability in the pollen response to rainfall, the diurnal precipitation changes, and the precipitation intensity in the city area. We determined the pollen response of four pollen types: Betula, Pinus, Poaceae, and Urtica, and we only included data from days that fulfilled restrictive criteria throughout all pollen seasons. We analysed a total of 81 days, which were divided into five groups according to precipitation intensity, the time of day of a precipitation event, and the type of pollen response to precipitation. Our results suggest that precipitation intensity was the dominant control on pollen concentrations; concentrations only decreased clearly under rainfall intensities of at least 5 mm•h−1 and this value we recommended as threshold value for long lasting decrease of pollen concentrations in our region. Lower intensity rainfall events resulted in no change in atmospheric pollen concentrations throughout the day. We noted the occurrence of increased pollen concentration immediately before and during rainfall events. Further, other parameters were also found to influence pollen concentrations in the atmosphere, including relative humidity, the time of day, and biological factors such as the plant phenophase or the phase of a pollen season.

中文翻译：

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降雨对大气花粉浓度日变化规律的影响

摘要 大气降水去除了对流层下部的大部分生物和化学污染物。然而，一些研究推断在降水事件和/或雷暴期间大气花粉浓度会增加，已知这会引发过敏反应（称为雷暴引发的哮喘）。本研究的目的是确定降水对空气中花粉浓度日变化的影响，特别关注降水事件的时间和强度。我们还考虑了其​​他气象因素对大气花粉浓度的影响。该研究于 2016 年至 2018 年在热舒夫（波兰东南部）进行。在这项研究中，我们使用了两个空气生物站和两个气象站来确定花粉对降雨的响应、昼夜降水变化和城市地区降水强度的潜在空间变异性。我们确定了四种花粉类型的花粉反应：桦木、松树、禾本科和荨麻，我们只包括在所有花粉季节满足限制标准的日子的数据。我们分析了总共 81 天，根据降水强度、降水事件发生的时间和花粉对降水的反应类型分为五组。我们的结果表明，降水强度是花粉浓度的主要控制因素；浓度仅在至少 5 mm•h−1 的降雨强度下才明显下降，我们建议将此值作为我们地区花粉浓度长期持续下降的阈值。较低强度的降雨事件导致全天大气花粉浓度没有变化。我们注意到在降雨事件之前和期间花粉浓度增加的情况。此外，还发现其他参数会影响大气中的花粉浓度，包括相对湿度、一天中的时间和生物因素，如植物物候期或花粉季节。我们注意到在降雨事件之前和期间花粉浓度增加的情况。此外，还发现其他参数会影响大气中的花粉浓度，包括相对湿度、一天中的时间和生物因素，如植物物候期或花粉季节。我们注意到在降雨事件之前和期间花粉浓度增加的情况。此外，还发现其他参数会影响大气中的花粉浓度，包括相对湿度、一天中的时间和生物因素，如植物物候期或花粉季节。