Dust event is a consequence of the wind erosion in which large amount of small particles enters the atmosphere and influenced the downwind area. Dust events impose negative socio-economic, health, and environmental impacts in vulnerable areas involving the Middle East (Middleton, 2017). The negative health impacts of dust were extensively assessed in previous studies. Dust may cause various diseases such as respiratory, cardiovascular, cardiopulmonary, and mental diseases (Griffin et al., 2007, Sandstrom and Forsberg, 2008, Goudie, 2014, Sprigg, 2016, Soleimani et al., 2020, Perez et al., 2012, Ma et al., 2016, Middleton, 2017).
The major dust sources in Middle East arise from degraded lands, dried agriculture and wetlands of Iraq and Syria, Sahara Desert, and Saudi Arabia's deserts during last two decades.
The dust particles reflect the biological and physiochemical characteristic of their dust sources and pathways. The origin and pathway of bioaerosol associated with air masses arriving at study were assessed with back trajectory models such as HYSPLIT model ( Innocente et al. 2017; Mu et al. 2020). Previous studies widely assessed the short and long-range transports of bioaerosol (Seifried et al., 2015, Smith et al., 2012, Nenes et al., 2013, Maki et al., 2013, Jeon et al., 2011, Polymenakou et al., 2008, Mazar et al., 2016, Meola et al., 2015, Lymperopoulou et al., 2016., Hervàs et al., 2009; Yamaguchi et al .,2012). Brief extend transport of bacteria for the most parts was considered due to similarities between airborne bacteria and bacteria from known nearby sources. Back trajectory models such as HYSPLIT were utilized in evaluating the long transport of bacteria.
Strong correlation has been reported between dust and total fungi concentrations. Abundance and diversity of fungi and bacteria were assessed to investigate the similarity between origin and downwind area. The results of these researches confirm that fungi and bacteria as bioaerosol could transport from dust sources to the downwind area (Chao et al. 2012; Yarahmadi et al. 2020).
Several approaches have been used to fungi identification in airborne dust including morphological and molecular approaches. Morphological approaches use macro- and micro characteristics of fungal genera or species (solimani et al. 2013; Goudarzi et al. 2016 ).
Molecular approaches include DNA extraction, PCR application and sequencing. The sequences were compared with the DNA sequences deposited in GenBank using the Basic Local Alignment Search Tool (BLAST) (http://blast.ncbi.nlm.nih.gov/Blast.cgi). (Kakikawa et al. 2008; Yarahmadi et al. 2020)
Also, QIIME virtual boxes have been applied to analyses raw DNA sequencing data based on billions of sequences from tens of thousands of samples. QIIME analyses are including OUT picking, taxanomic assignment, phylogenetic tree and diversity analyses (Bolyen et al. 2019, Mu et al. 2020)
Investigation of Similarity between fungi in source and target area has been utilized Richness and Diversity indices differences, phylogenetic tree, PCA analysis and pheatmap. There is little study about the source apportionments of airborne fungi. In these researches, Source Tracker using Bayesian method, estimate proportion of all source samples (Mu et al. 2020).
Previous studies, in south west of Iran, focused on airborne fungi identification using culture base approach and the relationship between dust and airborne fungi concentrations. (solimani et al. 2013; Goudarzi et al. 2016). But how biological characteristics of dust source influenced airborne fungi in downwind area not well studied.
The innovation of this research is quantifying impacts of dust sources on fungal composition of downwind area in the south west of Iran as one of the dustiest area in the world. To this purpose, following steps were carried out: The accurate fungi identification in dust source and downwind area using molecular approach, similarity investigation between origin and target area based on fungal richness and diversity indices and the dust sources contribution estimation to airborne fungi.
This study focuses on determining the effects of known dust sources on airborne fungi communities. Samples were collected from surface soil of possible sources (dried parts of Hoor Al-azim and Shadegan wetlands), and airborne dust from Arvand free zone, addressing the following questions: (1) what the composition and type of airborne fungi are? (2) What are the differences among airborne fungi at dusty and normal days? (3) What are the relationships among fungi in possible dust sources and airborne fungi? (4) Can the contributions of dust sources quantify in airborne fungi? (5) Can dust sources prioritize to prevent damage of dust events?