Cladosporium spp. and Alternaria spp. spores are dominating the airspora of Denmark. Currently, little is known about the influence of climate change on the fungal spore abundance in the air. The aim of this study was to examine temporal changes in airborne Alternaria and Cladosporium spores over 26 years. This is the first report of long-term airborne Cladosporium spore occurrence in Denmark. Air spore concentrations were obtained with a Burkard volumetric spore sampler placed in Copenhagen, Denmark, during June–September, 1990–2015. The highest monthly Spore integrals (SIn) for Alternaria were measured in August, whereas for Cladosporium July SIn was nearly as high as August SIn. Average Alternaria seasonal spore integral (SSIn) was 8615 Spores day m−3, while average 3-month (July–September) Cladosporium SIn was 375,533 Spores day m−3. Despite increasing annual temperature and decreasing relative humidity, we found a decreasing trend for Alternaria seasonal SIn (Slope = − 277, R2 = 0.38, p < 0.05), Alternaria (Slope = − 31, R2 = 0.27, p < 0.05) and Cladosporium (Slope = − 440, R2 = 0.23, p < 0.05) annual peak concentrations. We did not find any statistically significant trends for airborne Alternaria seasonal characteristics and duration, and likewise for Cladosporium 3-month SIn and peak concentration dates. Mean temperature was the main meteorological factor affecting daily spore concentrations. However, effect of meteorological parameters on daily spore concentrations was stronger for Cladosporium (R2 = 0.41) than for Alternaria (R2 = 0.21). Both genera had diurnal peaks during the day hours, earlier for Cladosporium (11:30–14:30) and later for Alternaria (15:00–19:00). Although Alternaria and Cladosporium daily concentrations were moderately correlated (Spearman’s correlation coefficient: rs = 0.55, p < 0.05), their overall annual indices were different, which indicates different sources and different factors determining spore release. We explain temporal decreasing trends in Alternaria SSIn by growing urbanisation around Copenhagen and by changes in agricultural practices.

中文翻译：

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丹麦哥本哈根 26 年来空气中枝孢菌和链格孢菌的浓度

枝孢菌属 和链格孢属。孢子在丹麦的空气孢子中占主导地位。目前，人们对气候变化对空气中真菌孢子丰度的影响知之甚少。本研究的目的是检查 26 年来空气传播的链格孢菌和枝孢菌孢子的时间变化。这是丹麦长期空气传播枝孢菌孢子发生的第一份报告。空气孢子浓度是在 1990 年 6 月至 2015 年 9 月期间使用放置在丹麦哥本哈根的 Burkard 体积孢子采样器获得的。链格孢菌最高的月孢子积分 (SIn) 是在 8 月测量的，而枝孢菌 7 月 SIn 几乎与 8 月 SIn 一样高。平均链格孢属季节性孢子积分 (SSIn) 为 8615 个孢子日 m-3，而平均 3 个月（7 月至 9 月）枝孢菌 SIn 为 375,533 个孢子日 m-3。尽管年温升高和相对湿度降低，我们发现链格孢属季节性 SIn（斜率 = - 277，R2 = 0.38，p < 0.05）、链格孢菌（斜率 = - 31，R2 = 0.27，p < 0.05）和枝孢霉呈下降趋势（斜率 = − 440，R2 = 0.23，p < 0.05）年度峰值浓度。我们没有发现空气传播的链格孢属季节性特征和持续时间的任何统计上显着的趋势，枝孢菌 3 个月的 SIn 和峰值浓度日期也是如此。平均温度是影响每日孢子浓度的主要气象因素。然而，气象参数对枝孢菌 (R2 = 0.41) 的每日孢子浓度的影响强于链格孢 (R2 = 0.21)。这两个属在白天都有昼夜高峰，枝孢属（11:30–14:30）较早，链格孢属较晚（15:00–19：00）。尽管链格孢和枝孢菌的日浓度呈中等相关（Spearman 相关系数：rs = 0.55，p < 0.05），但它们的总体年度指数不同，这表明决定孢子释放的来源和因素不同。我们通过哥本哈根周围城市化的发展和农业实践的变化来解释链格孢 SSIn 的时间下降趋势。