(edition) Initial assessment of Alternaria spores in Mar del Plata, Argentina: Trends, meteorological effects and sources.

. LATORRE, F. & ABUD SIERRA, M.L.

AEROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2024

0393-5965

Alternaria, a fungus globally recognized for its impact on allergic diseases and crop yields, prompted the first study of spore behavior given its prevalent presence in the atmosphere of Mar del Plata, Argentina. The primary objective was to explore spore abundance patterns across various time scales, aiming to identify potential spore sources and discern meteorological factors contributing to count increments. Data collected over a six-year period through aerobiological monitoring, using a volumetric and continuous spore trap from September 2013 to August 2019, were employed to examine interannual, seasonal, and daily patterns. Hourly spore data collected between September 2021 and July 2022 were crossed and analyzed simultaneously with data from a newly automated meteorological station installed adjacent to the aerobiological device. Alternaria spores, on average, represented 21% of the aerobiota when considered alongside pollen grains. The yearly sum of mean concentrations ranged between 2116 and 5323 spores*m-3air*year-1 in 2017-18 and 2013-14, respectively. A negative correlation of these values was observed over the period, though not statistically significant. A change in behavior occurred in 2016-17, marked by an increase in spore capture contrary to the decreasing tendency, and the appearance of a second peak in the annual curve. As possible responsibles, meteorological factors and/or change in the main sources or in species contribution were proposed… Between 80% and 85% of days throughout each of the studied years presented airborne spores, with peak concentrations in December and April; on average, 84% was accumulated in summer and autumn. Only 1% of the days with spores exceeded a concentration threshold of 100 s/m3. Days with this highest value were windier and colder than other days with spores; for temperature, its effect was supported by a significant rank correlation (Rs=0.5). The peak hour of the day was recorded at four in the afternoon, with 50% of the daily total observed between noon and 6 p.m., as confirmed by agglomeration analysis. This daily pattern of elevated values showed a significant correlation with higher temperatures (Rs=0.77), stronger winds (Rs=0.87), and the period of lowest humidity of the day (Rs=-0.73). The daily distribution index was 0.09, indicating that the sources of spores abounded in remote areas and that the particles were transported over medium to long distances. In 73% of the hours with spores, the winds blew from the directions where horticultural areas are concentrated in the peri-urban-rural belt, mostly from Northwest, West-Northwest, and West.