Exposure to elevated air pollution levels can aggravate pollen allergy symptoms. The aim of this study was to investigate the relationships between airborne birch (Betula) pollen, urban air pollutants NO2, O3 and PM10 and their effects on antihistamine demand in Gothenburg and Malmö, Sweden, 2006–2012. Further, the influence of large-scale weather pattern on pollen-/pollution-related risk, using Lamb weather types (LWTs), was analysed. Daily LWTs were obtained by comparing the atmospheric pressure over a 16-point grid system over southern Sweden (scale ~3000 km). They include two non-directional types, cyclonic (C) and anticyclonic (A) and eight directional types depending on the wind direction (N, NE, E…). Birch pollen levels were exceptionally high under LWTs E and SE in both cities. Furthermore, LWTs with dry and moderately calm meteorological character (A, NE, E, SE) were associated with strongly elevated air pollution (NO2 and PM10) in Gothenburg. For most weather situations in both cities, simultaneously high birch pollen together with high air pollution had larger over-the-counter (OTC) sales of antihistamines than situations with high birch pollen alone. LWTs NE, E, SE and S had the highest OTC sales in both cities. In Gothenburg, the city with a higher load of both birch pollen and air pollution, the higher OTC sales were especially obvious and indicate an increased effect on allergic symptoms from air pollution. Furthermore, Gothenburg LWTs A, NE, E and SE were associated with high pollen and air pollution levels and thus classified as high-risk weather types. In Malmö, corresponding high-risk LWTs were NE, E, SE and S. Furthermore, occurrence of high pollen and air pollutants as well as OTC sales correlated strongly with vapour pressure deficit and temperature in Gothenburg (much less so in Malmö). This provides evidence that the combination of meteorological properties associated with LWTs can explain high levels of birch pollen and air pollution. Our study shows that LWTs represent a useful tool for integrated daily air quality forecasting/warning.

中文翻译：

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瑞典两个城市桦树花粉、空气污染和天气类型的关系及其对抗组胺药购买的影响

暴露于升高的空气污染水平会加重花粉过敏症状。本研究的目的是调查 2006-2012 年瑞典哥德堡和马尔默空气传播的桦木 (Betula) 花粉、城市空气污染物 NO2、O3 和 PM10 之间的关系及其对抗组胺药需求的影响。此外，使用羔羊天气类型 (LWT) 分析了大规模天气模式对花粉/污染相关风险的影响。每日 LWT 是通过比较瑞典南部 16 点网格系统（规模约 3000 公里）的大气压力获得的。它们包括两种非定向类型，气旋 (C) 和反气旋 (A) 以及八种定向类型，具体取决于风向（N、NE、E...）。在两个城市的 LWT E 和 SE 下，桦木花粉水平异常高。此外，具有干燥和中等平静气象特征（A、NE、E、SE）的 LWT 与哥德堡的空气污染（NO2 和 PM10）严重升高有关。对于这两个城市的大多数天气情况，同时高桦树花粉和高空气污染比单独高桦树花粉的情况下抗组胺药的非处方 (OTC) 销售量更大。LWT NE、E、SE 和 S 在这两个城市的 OTC 销售额最高。在桦树花粉和空气污染负荷较高的哥德堡，OTC 销售额的增加尤为明显，表明对空气污染引起的过敏症状的影响增加。此外，哥德堡 LWT A、NE、E 和 SE 与高花粉和空气污染水平相关，因此被归类为高风险天气类型。在马尔默，相应的高风险 LWT 为 NE、E、SE 和 S。此外，高花粉和空气污染物的发生以及 OTC 销售与哥德堡的蒸气压不足和温度密切相关（马尔默的情况更小）。这提供了证据，表明与 LWT 相关的气象特性的组合可以解释高水平的桦树花粉和空气污染。我们的研究表明，LWT 是一种用于综合日常空气质量预测/警告的有用工具。