Building-integrated agriculture: A first assessment of aerobiological air quality in rooftop greenhouses (i-RTGs).

Building-integrated rooftop greenhouse (i-RTG) agriculture has intensified in recent years, due to the growing interest in the development of new agricultural spaces and in the promotion of food self-sufficiency in urban areas. This paper provides a first assessment of the indoor dynamics of bioaerosols in an i-RTG, with the aim of evaluating biological air quality in a tomato greenhouse near Barcelona. It evaluates the greenhouse workers' exposure to airborne pollen and fungal spores in order to prevent allergy problems associated with occupational tasks. Moreover, it evaluates whether the quality of the hot air accumulated in the i-RTG is adequate for recirculation to heat the building. Daily airborne pollen and fungal spore concentrations were measured simultaneously in the indoor and outdoor environments during the warm season. A total of 4,924pollengrains/m3 were observed in the i-RTG, with a peak of 334pollengrains/m3day, and a total of 295,038 fungal spores were observed, reaching a maximum concentration of 26,185spores/m3day. In general, the results showed that the most important source of pollen grains and fungal spores observed indoors was the outdoor environment. However, Solanaceae pollen and several fungal spore taxa, such as the allergenic Aspergillus/Penicillium, largely originated inside the greenhouses or were able to colonize the indoor environment under favourable growing conditions. Specific meteorological conditions and agricultural management tasks are related to the highest observed indoor concentrations of pollen grains and fungal spores. Therefore, preventive measures have been suggested in order to reduce or control the levels of bioaerosols indoors (to install a system to interrupt the recirculation of air to the building during critical periods or to implement appropriate air filters in ventilation air ducts). This first evaluation could help in making decisions to prevent the development of fungal diseases, specifically those due to Oidium and Torula.

Are the Pyrenees a barrier for the transport of birch (Betula) pollen from Central Europe to the Iberian Peninsula?

This work provides a first assessment of the possible barrier effect of the Pyrenees on the atmospheric transport of airborne pollen from Europe to the North of the Iberian Peninsula. Aerobiological data recorded in three Spanish stations located at the eastern, central and western base of the Pyrenees in the period 2004-2014 have been used to identify the possible long range transport episodes of Betula pollen. The atmospheric transport routes and the origin regions have been established by means of trajectory analysis and a source receptor model. Betula pollen outbreaks were associated with the meteorological scenario characterized by the presence of a high-pressure system overm over Morocco and Southern Iberian Peninsula. France and Central Europe have been identified as the probable source areas of Betula pollen that arrives to Northern Spain. However, the specific source areas are mainly determined by the particular prevailing atmospheric circulation of each location. Finally, the Weather Research and Forecasting model highlighted the effect of the orography on the atmospheric transport patterns, showing paths through the western and easternmost lowlands for Vitoria-Gasteiz and Bellaterra respectively, and the direct impact of air flows over Vielha through the Garona valley.

Is long range transport of pollen in the NW Mediterranean basin influenced by Northern Hemisphere teleconnection patterns?

Climatic oscillations triggered by the atmospheric modes of the Northern Hemisphere teleconnection patterns have an important influence on the atmospheric circulation at synoptic scale in Western Mediterranean Basin. Simultaneously, this climate variability could affect a variety of ecological processes. This work provides a first assessment of the effect of North Atlantic Oscillation (NAO), Arctic Oscillation (AO) and Western Mediterranean Oscillation (WeMO) on the atmospheric long-range pollen transport episodes in the North-Eastern Iberian Peninsula for the period 1994-2011. Alnus, Ambrosia, Betula, Corylus and Fagus have been selected as allergenic pollen taxa with potential long-range transport associated to the Northern Hemisphere teleconnection patterns in the Western Mediterranean Basin. The results showed an increase of long range pollen transport episodes of: (1) Alnus, Corylus and Fagus from Western and Central Europe during the negative phase of annual NAO and AO; (2) Ambrosia, Betula and Fagus from Europe during the negative phase of winter WeMO; (3) Corylus and Fagus from Mediterranean area during the positive phase of the annual AO; and (4) Ambrosia from France and Northern Europe during the positive phase of winter WeMO. Conversely, the positive phase of annual NAO and AO are linked with the regional transport of Alnus, Betula and Corylus from Western Iberian Peninsula. The positive phase of annual WeMO was also positively correlated with regional transport of Corylus from this area.

Source areas and long-range transport of pollen from continental land to Tenerife (Canary Islands).

The Canary Islands, due to their geographical position, constitute an adequate site for the study of long-range pollen transport from the surrounding land masses. In this study, we analyzed airborne pollen counts at two sites: Santa Cruz de Tenerife (SCO), at sea level corresponding to the marine boundary layer (MBL), and Izaña at 2,367 m.a.s.l. corresponding to the free troposphere (FT), for the years 2006 and 2007. We used three approaches to describe pollen transport: (1) a classification of provenances with an ANOVA test to describe pollen count differences between sectors; (2) a study of special events of high pollen concentrations, taking into consideration the corresponding meteorological synoptic pattern responsible for transport and back trajectories; and (3) a source-receptor model applied to a selection of the pollen taxa to show pollen source areas. Our results indicate several extra-regional pollen transport episodes to Tenerife. The main provenances were: (1) the Mediterranean region, especially the southern Iberian Peninsula and Morocco, through the trade winds in the MBL. These episodes were characterized by the presence of pollen from trees (Casuarina, Olea, Quercus perennial and deciduous types) mixed with pollen from herbs (Artemisia, Chenopodiaceae/Amaranthaceae and Poaceae wild type). (2) The Saharan sector, through transport at the MBL level carrying pollen principally from herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type) and, in one case, Casuarina pollen, uplifted to the free troposphere. And (3) the Sahel, characterized by low pollen concentrations of Arecaceae, Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type in sporadic episodes. This research shows that sporadic events of long-range pollen transport need to be taken into consideration in Tenerife as possible responsible agents in respiratory allergy episodes. In particular, it is estimated that 89-97% of annual counts of the highly allergenous Olea originates from extra-regional sources in southern Iberia and northern Africa.