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Background: Ambient pollen exposure causes nasal, ocular, and pulmonary symptoms in allergic individuals, but the shape of the exposure–response association is not well characterized. We evaluated this association and determined (1) whether symptom severity differs between subpopulations; (2) how the association changes over the course of the pollen season; and (3) which pollen exposure time lags affect symptoms. Methods: Adult study participants (n = 396) repeatedly scored severity of nasal, ocular, and pulmonary allergic symptoms, resulting in three composite symptom scores. We calculated hourly individually relevant pollen exposure to seven allergenic plants (alder, ash, birch, hazel, grasses, mugwort, and ragweed) considering personal sensitization and exposure time lags of up to 96 h. We fitted generalized additive mixed models, with a random personal intercept, adjusting for weather and air pollution as potential time‐varying confounders. Results: We identified a clear nonlinear positive association between pollen exposure and ocular and nasal symptom severity in the pollen allergy group: Symptom severity increased steeply with increasing exposure initially, but attenuated beyond approximately 80 pollen/m3. We found no evidence of an exposure threshold, below which no symptoms occur. While recent pollen exposure in the last approximately 5 h affected symptoms most, associations lingered for up to 60 h. Grass pollen exposure (compared to tree pollen) and younger age (18–30 years, as opposed to 30–65 years) were both associated with higher nasal and ocular symptom severity. Conclusions: The lack of a threshold and attenuated dose–response curve may have implications for pollen warning systems, which may be revised to include multiday pollen concentrations in the future. [ABSTRACT FROM AUTHOR]

The Asian chestnut gall wasp (ACGW; Dryocosmus kuriphilus Yasumatsu, Hymenoptera, Cynipidae) is considered as one of the most dangerous pests of the genus Castanea. In southern Switzerland, repeated heavy ACGW attacks prevented chestnut trees from vegetating normally for years before the arrival and spread of the biological control agent Torymus sinensis (Kamijo, Hymenoptera, Torymidae). This resulted in a greatly reduced green biomass and flower production. In this paper, we analyze the impact of such an ecosystem alteration of the environment on the composition of produced honey. Six beekeepers were chosen from sites with different densities of chestnut trees, each of which providing series of honey samples from 2010 to 2016. We determined the chestnut component in the honeys via a combined chemical and sensory approach, and correlated the obtained results with the degree of yearly ACGW-induced crown damage and weather conditions during the period in question in the surrounding chestnut stands. The chestnut component in the analyzed honey sample series showed a strong correlation with the degree of ACGW-induced crown damage, whereas meteorological conditions of the corresponding year had a very marginal effect. Decreases in the chestnut component of the honey were statistically significant starting from a ACGW infestation level of 30%. [ABSTRACT FROM AUTHOR]

The significantly higher temperatures in city centres compared to rural areas have a negative effect on the health of the city population. Depending on the size of the city, the building density, the proportion of vegetation and ventilation, the urban heat island (UHI) effects can differ in magnitude. The goal of the study was to provide a climatological overview of the intensity of the UHI in five main Swiss cities with more than 130'000 inhabitants.The UHI was studied by comparing data series of weather stations located in city centres with weather stations in the rural vicinity. The UHI is calculated as temperature difference between the urban and the rural station. The rural stations were selected from the network of the Federal Office of Meteorology and Climatology MeteoSwiss, while the urban stations were taken from various national, cantonal and university observational networks. Data series of a length of 6 to 26 years were analysed. Following the classification of Stewart and Oke (2012), the urban stations were classified as Local Climate Zones LCZ 5 (open midrise) or LCZ 2 (compact midrise) with paved grounds.The UHI is present in all investigated cities during the whole year. Maxima are reached in summer, especially at night. Night temperatures in city centres are on average over 2 K higher in summer than in rural areas. In less densely built-up areas they are between 1 and 2 K higher. Nighttime city temperatures can be up to 6-7 K higher than in rural areas in the vicinity. During the warmest nights, the temperature in the city centres does not drop below 24-25 °C. The number of tropical nights in cities is significantly higher than in rural areas, while the number of hot days is only slightly higher. An exception to this are the monitoring stations in Basel, where the number of hot days is also significantly higher. They represent locations in the immediate vicinity of asphalt and buildings, which warm up strongly during the day. A comparison of the occurrence UHI with weather classes confirms, that the urban heat island is most pronounced during high-pressure periods, i.e. in windless, low-cloud and high-radiation weather conditions. For the Zurich stations, the diagnostic model from Theeuwes et al. (2017) was adapted to estimate the daily maximum heat island effect on the basis of weather data from the rural station, the vegetation fraction and the sky view factor in the city. The model revealed suitable results with mean absolute errors (MAE) of 0.75 to 1.53. With climate change and the expected population growth in cities and agglomerations, the issue of heat stress in cities is becoming increasingly important. It is therefore important to collect measurement data on the characteristics and changes of the urban heat island and to model and project future changes the urban climate. [ABSTRACT FROM AUTHOR]

Background: There is evidence that global anthropogenic climate change may be impacting floral phenology and the temporal and spatial characteristics of aero-allergenic pollen. Given the extent of current and future climate uncertainty, there is a need to strengthen predictive pollen forecasts., Methods: The study aims to use CatBoost (CB) and deep learning (DL) models for predicting the daily total pollen concentration up to 14 days in advance for 23 cities, covering all five continents. The model includes the projected environmental parameters, recent concentrations (1, 2 and 4 weeks), and the past environmental explanatory variables, and their future values., Results: The best pollen forecasts include Mexico City (R 2 (DL_7) ≈ .7), and Santiago (R 2 (DL_7) ≈ .8) for the 7th forecast day, respectively; while the weakest pollen forecasts are made for Brisbane (R 2 (DL_7) ≈ .4) and Seoul (R 2 (DL_7) ≈ .1) for the 7th forecast day. The global order of the five most important environmental variables in determining the daily total pollen concentrations is, in decreasing order: the past daily total pollen concentration, future 2 m temperature, past 2 m temperature, past soil temperature in 28-100 cm depth, and past soil temperature in 0-7 cm depth. City-related clusters of the most similar distribution of feature importance values of the environmental variables only slightly change on consecutive forecast days for Caxias do Sul, Cape Town, Brisbane, and Mexico City, while they often change for Sydney, Santiago, and Busan., Conclusions: This new knowledge of the ecological relationships of the most remarkable variables importance for pollen forecast models according to clusters, cities and forecast days is important for developing and improving the accuracy of airborne pollen forecasts., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: Pollen exposure is associated with respiratory symptoms in children and adults. However, the association of pollen exposure with respiratory symptoms during infancy, a particularly vulnerable period, remains unclear. We examined whether pollen exposure is associated with respiratory symptoms in infants and whether maternal atopy, infant's sex or air pollution modifies this association., Methods: We investigated 14,874 observations from 401 healthy infants of a prospective birth cohort. The association between pollen exposure and respiratory symptoms, assessed in weekly telephone interviews, was evaluated using generalized additive mixed models (GAMMs). Effect modification by maternal atopy, infant's sex, and air pollution (NO 2 , PM 2.5 ) was assessed with interaction terms., Results: Per infant, 37 ± 2 (mean ± SD) respiratory symptom scores were assessed during the analysis period (January through September). Pollen exposure was associated with increased respiratory symptoms during the daytime (RR [95% CI] per 10% pollen/m 3 : combined 1.006 [1.002, 1.009]; tree 1.005 [1.002, 1.008]; grass 1.009 [1.000, 1.23]) and nighttime (combined 1.003 [0.999, 1.007]; tree 1.003 [0.999, 1.007]; grass 1.014 [1.004, 1.024]). While there was no effect modification by maternal atopy and infant's sex, a complex crossover interaction between combined pollen and PM 2.5 was found (p-value 0.003)., Conclusion: Even as early as during the first year of life, pollen exposure was associated with an increased risk of respiratory symptoms, independent of maternal atopy and infant's sex. Because infancy is a particularly vulnerable period for lung development, the identified adverse effect of pollen exposure may be relevant for the evolvement of chronic childhood asthma., (© 2022 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)