Table S1: The limits of detection of extrolites in dust samples

Metabolite LOD (ng/g) Sterigmatocystin 0.252 Methoxysterigmatocystin 0.896 Versicolorin C.2 4.029 Averantin 0.400 Averufin 0.717 8-O-Methylaverufin 0.750 seco-Sterigmatocystin 2.443 3-Nitropropionic acid 9.733 Methylsulochrin 1.230 Fumigaclavine C 3.523 Fumigaclavine 1.504 Fumiquinazolin D 5.417 Sydowinin A 13.014 Deoxynivalenol 12.593 Nivalenol 3.463 T-2 toxin 1.850 Zearalenone 2.332 Moniliformin 4.575 Beauvericin 0.810 Enniatin A 0.031 Enniatin A1 0.475 Enniatin B 0.095 Enniatin B1 0.328 Enniatin B2 0.768 Enniatin B3 0.004 EpiEquisetin 0.429 Equisetin 2.572 Fusaric acid 76.552 Fusarinolic acid 22.400 Apicidin 0.881 Culmorin 5.909 15-Hydroxyculmorin 7.460 5-Hydroxyculmorin 18.691 Siccanol 18.691 Fusapyron 3.290 Deoxyfusapyron 3.587 Aurofusarin 4.748 Antibiotic Y 18.691 Chrysogin 2.505 W493 2.874 Ochratoxin A 3.271 Citrinin 2.788 Dihydrocitrinone 3.459 Mycophenolic acid 0.920 Andrastin A 4.052 Verrucofortine 0.103 Viridicatin 4.458 Viridicatol 27.242 Agroclavine 0.406 Chanoclavin 0.517 Griseofulvin 15.000 Dechlorogriseofulvin 4.758 Secalonic acid D 3.857 O-Methylviridicatin 0.182 7-Hydroxypestalotin 2.205 Pestalotin 2.874 Questiomycin A 3.695 Quinolactacin A 0.175 Roquefortine C 1.566 Curvularin.2 7.189 Marcfortine A 0.158 Cycloaspeptide A 4.184 Cyclopenin 0.411 Cyclopenol 7.915 Aurantiamin A 3.257 Barceloneic acid 21.284 Cyclopeptine 0.652 Flavoglaucin 12.194 Rugulovasine A 2.411 Tenuazonic acid 135.000 Alternariol 11.246 Alternariolmethylether 0.709 Altersetin 1.745 Tentoxin 0.567 Infectopyron 60.199 Ascochlorin 1.250 Bassianolide 0.560 Monocerin 2.760 Rubellin D 0.386 Abscisic acid 4.834 Valinomycin 2.104 Nonactin 0.544 Monactin 1.232 Dinactin 1.232 Usnic acid 1.315 Lecanoic acid 1.232 Biochanin 22.400 Daidzein 22.400 Daidzin 22.400 Formonetin 22.400 Genistein 22.400 Genistin 22.400 Glycitein 22.400 Glycitin 22.400 Ononin 22.400 Asperphenamate 0.447 Brevianamid F 1.486 cyclo(L-Pro-L-Tyr) 13.198 cyclo(L-Pro-L-Val) 18.468 Emodin 1.569 Endocrocin 93.151 Iso-Rhodoptilometrin 0.955 Lotaustralin 21.596 N-Benzoyl-Phenylalanine 4.000 Neoechinulin A 6.428 Rugulusovin 1.199 Skyrin 1.146 Tryptophol 22.272

Table S2. Diversity of bacterial/archeal genera in dust and air samples

Abundance of bacterial/archeal genera in samples. %* Domain Phylum Genera Dust Air Methanobrevibacter 0.037 0.215 Archaea Euryarchaeota Methanosphaera 0.000 0.014 Actinomyces 0.048 2.777 N09 0.002 0.041 Trueperella 0.031 0.273 Varibaculum 0.000 0.002 Salana 0.002 0.010 Brevibacterium 0.514 0.869 Actinotalea 0.002 0.002 Cellulomonas 0.038 0.316 Demequina 0.002 0.002 Oerskovia 0.006 0.005 Corynebacterium 2.602 8.768 Brachybacterium 0.195 0.520 Dermacoccus 0.000 0.010 Dietzia 0.042 0.403 Blastococcus 0.000 0.011 Glycomyces 0.002 0.026 Gordonia 0.000 0.002 Phycicoccus 0.061 0.101 Kineococcus 0.011 0.023 Rhodoluna 0.002 0.000 Clavibacter 0.006 0.001 Cryocola 0.168 0.163 Curtobacterium 0.013 0.013 Leucobacter 0.041 0.363 Microbacterium 0.230 0.643 Pseudoclavibacter 0.004 0.031 Rathayibacter 0.041 0.093 Arthrobacter 0.306 0.605 Kocuria 0.044 0.057 Micrococcus 0.018 0.008 Nesterenkonia 0.009 0.912 Renibacterium 0.000 0.073 Rothia 0.000 0.004 Mycobacterium 0.008 0.011 Rhodococcus 0.046 0.083 Aeromicrobium 0.019 0.162 Nocardioides 0.002 0.022 Prauseria 0.011 0.025 Thermobifida 0.006 0.002 Promicromonospora 0.000 0.029 Xylanimicrobium 0.011 0.224 Propionibacterium 0.002 0.030 Tessaracoccus 0.006 0.012 Actinomycetospora 0.002 0.000 Prauserella 0.002 0.024 Saccharomonospora 0.009 0.096 Saccharopolyspora 0.006 1.541 Sanguibacter 0.024 0.036 Streptomyces 0.000 0.024 Nonomuraea 0.000 0.013 Yaniella 0.026 0.150 Bifidobacterium 0.109 0.239 Adlercreutzia 0.004 0.164 Atopobium 0.000 0.073 Collinsella 0.006 0.012 Bacteroides 1.758 5.634 Dysgonomonas 0.000 0.022 Paludibacter 0.192 1.216 Parabacteroides 0.009 0.008 Porphyromonas 0.000 0.001 Odoribacter 0.004 0.038 CF231 0.238 0.665 Paraprevotella 0.011 0.018 YRC22 0.029 0.087 Prevotella 0.136 0.226 Algoriphagus 0.004 0.037 Dyadobacter 0.018 0.052 Hymenobacter 0.354 0.614 Spirosoma 0.000 0.024 Brumimicrobium 0.009 0.112 Fluviicola 0.004 0.028 Aequorivita 0.000 0.124 Flavobacterium 0.009 0.019 Myroides 0.085 0.920 Ulvibacter 0.002 0.013 Chryseobacterium 0.098 0.209 Cloacibacterium 0.000 0.004 Elizabethkingia 0.000 0.002 Ornithobacterium 0.000 0.041 Wautersiella 0.031 0.089 Weeksella 0.018 0.206 Parapedobacter 0.022 0.264 Pedobacter 0.146 0.382 Sphingobacterium 0.020 0.114 Sediminibacterium 0.004 0.141 T78 0.000 0.013 Fibrobacter 0.019 0.046 Alicyclobacillus 0.000 0.046 Anoxybacillus 0.002 0.243 Bacillus 0.017 0.429 Geobacillus 0.000 0.005 Natronobacillus 0.024 0.041 Brochothrix 0.000 0.005 Paenibacillus 0.004 0.038 Lysinibacillus 0.004 0.016 Planomicrobium 0.004 0.025 Solibacillus 0.035 0.589 Sporosarcina 0.004 0.093 Jeotgalicoccus 0.335 1.243 Macrococcus 0.002 0.000 Salinicoccus 0.015 0.000 Staphylococcus 74.388 3.278 Exiguobacterium 0.002 0.020 Abiotrophia 1.266 4.665 Aerococcus 0.245 1.373 Alkalibacterium 0.000 0.005 Alloiococcus 0.015 0.071 Facklamia 0.695 4.038 Marinilactibacillus 0.022 0.000 Carnobacterium 0.004 0.070 Desemzia 0.011 0.018 Trichococcus 0.015 0.172 Enterococcus 0.026 0.462 Lactobacillus 0.050 0.202 Pediococcus 0.004 0.000 Leuconostoc 0.112 0.412 Weissella 0.072 0.682 Lactococcus 0.002 0.022 Streptococcus 0.009 0.032 Turicibacter 0.118 0.189 Clostridium 1.871 6.203 Proteiniclasticum 0.007 0.195 Sarcina 0.000 0.011 Anaerostipes 0.033 0.046 Blautia 0.013 0.048 Butyrivibrio 0.052 0.314 Coprococcus 0.024 0.147 Dorea 0.085 0.189 Epulopiscium 0.015 0.082 Roseburia 0.022 0.023 Ruminococcus 3.320 11.391 Peptococcus 0.015 0.058 Faecalibacterium 0.002 0.000 Oscillospira 0.158 0.641 Phascolarctobacterium 0.066 0.470 Guggenheimella 0.006 0.101 Anaerococcus 0.008 0.256 GW-34 0.020 0.154 Gallicola 0.002 0.032 Helcococcus 0.007 0.168 Peptoniphilus 0.002 0.000 Sedimentibacter 0.000 0.036 Tissierella_Soehngenia 0.006 0.206 ph2 0.007 0.072 Coprobacillus 0.000 0.022 Erysipelothrix 0.057 0.398 RFN20 0.000 0.013 Eubacterium 0.009 0.017 Brevundimonas 0.006 0.000 Mycoplana 0.012 0.067 Ochrobactrum 0.009 0.063 Devosia 0.020 0.166 Methylobacterium 0.092 0.190 Mesorhizobium 0.004 0.010 Nitratireductor 0.015 0.119 Agrobacterium 0.336 0.327 Amaricoccus 0.002 0.001 Anaerospora 0.000 0.004 Paracoccus 0.022 0.251 Rhodobacter 0.002 0.002 Rubellimicrobium 0.002 0.000 Acetobacter 0.008 0.000 Gluconobacter 0.000 0.001 Azospirillum 0.000 0.004 Ehrlichia 0.278 1.290 Kaistobacter 0.017 0.020 Novosphingobium 0.011 0.002 Sphingomonas 1.459 1.762 Achromobacter 0.000 0.020 Oligella 0.051 0.563 Sutterella 0.013 0.020 Tetrathiobacter 0.004 0.002 Burkholderia 0.000 0.035 Alicycliphilus 0.014 0.035 Acidovorax 0.000 0.012 Comamonas 0.004 0.016 Hydrogenophaga 0.000 0.007 Polaromonas 0.002 0.001 Variovorax 0.013 0.014 Cupriavidus 0.000 0.008 Herbaspirillum 0.000 0.001 Janthinobacterium 0.485 0.718 Polynucleobacter 0.002 0.000 Ralstonia 0.000 0.540 Dechloromonas 0.000 0.032 Desulfobulbus 0.000 0.013 Desulfovibrio 0.031 0.352 Arcobacter 0.009 0.076 Campylobacter 0.002 0.040 Aeromonas 0.002 0.014 Ruminobacter 0.022 0.030 Cellvibrio 0.014 0.067 Idiomarina 0.000 0.163 Pseudidiomarina 0.000 0.167 Shewanella 0.000 0.008 Enterobacter 0.020 0.106 Erwinia 0.190 0.228 Proteus 0.006 0.000 Providencia 0.000 0.005 Serratia 0.000 0.013 Sodalis 0.000 0.011 Rickettsiella 0.035 0.000 Legionella 0.000 0.005 Alcanivorax 0.004 0.041 Candidatus Portiera 0.000 0.121 Chromohalobacter 0.000 0.002 Halomonas 0.021 3.111 Oleibacter 0.000 0.022 Actinobacillus 0.002 0.000 Acinetobacter 0.212 1.195 Alkanindiges 0.000 0.005 Psychrobacter 0.420 2.302 Pseudomonas 0.123 0.917 Methylophaga 0.000 0.044 Vibrio 0.004 0.066 Luteimonas 0.021 0.078 Stenotrophomonas 0.002 0.005 Xanthomonas 0.000 0.016 Treponema 0.017 0.143 Acholeplasma 0.004 1.808 Tenericutes Anaeroplasma 0.010 0.137 Akkermansia 0.074 0.404 Luteolibacter 0.000 0.004 Other 4.259 10.204 Unidentified# 0.322 0.303 *percentage share of studied genera greater than 0.001% #sequences that could not be classified into any phylogenetic group were assigned as unidentified.

Table S3. Diversity of fungal genera in dust and air samples

Abundance of fungal genera in samples. %* Phylum Order Genera Dust Air Cladosporium 6.614 0.514 Dissoconium 0.004 0.000 Cercospora 0.001 0.000 Mycosphaerella 3.589 15.152 Zymoseptoria 0.007 0.000 Aureobasidium 0.018 0.001 Boeremia 0.001 0.000 Didymella 0.005 0.000 Epicoccum 0.773 0.854 Neoascochyta 0.096 0.000 Paraphaeosphaeria 0.002 0.000 Lophiotrema 0.001 0.000 Periconia 0.001 0.000 Septoriella 0.002 0.000 Alternaria 1.882 5.553 Bipolaris 0.002 0.000 Pyrenophora 0.005 0.000 Stemphylium 0.009 0.000 Westerdykella 0.005 0.000 Aspergillus 23.239 7.816 Penicillium 0.020 0.087 Xeromyces 0.001 0.000 Talaromyces 0.007 0.253 Thermomyces 0.086 0.333 Ascosphaera 0.004 0.146 Erysiphe 0.002 0.000 Xenopolyscytalum 0.001 0.000 Botrytis 0.001 0.000 Pseudogymnoascus 0.001 0.000 Debaryomyces 2.000 2.982 Wickerhamomyces 0.001 0.346 Kregervanrija 0.002 0.318 Pichia 0.004 0.000 Saturnispora 0.007 0.017 Issatchenkia 0.202 0.857 Kazachstania 0.002 0.269 Saccharomyces 0.001 0.003 Candida 2.561 8.313 Plectosphaerella 0.053 0.000 Lecanicillium 0.007 0.000 Acremonium 0.038 0.000 Sarocladium 0.024 0.558 Trichothecium 0.000 0.232 Fusarium 0.175 1.949 Stachybotrys 0.001 0.000 Melanospora 0.004 0.000 Microascus 0.026 0.010 Chaetomium 0.049 0.811 Myceliophthora 0.001 0.087 Nigrospora 0.055 0.000 Monographella 0.019 0.000 Taphrinomycetes Taphrina 0.001 0.000 Cystidiodontia 0.003 0.186 Athelia 0.000 0.001 Exidia 0.001 0.000 Agaricomycetes Sistotrema 0.000 0.001 Ceratobasidium 0.001 0.000 Trametes 0.001 0.002 Fomes 0.000 0.002 Agaricostilbomycetes Sterigmatomyces 0.569 0.000 Occultifur 0.000 0.001 Buckleyzyma 0.001 0.000 Cystobasidiomycetes Symmetrospora 0.028 0.000 Erythrobasidium 0.002 0.000 Malassezia 0.016 0.005 Leucosporidium 0.002 0.203 Malasseziomycetes Rhodotorula 0.002 0.000 Sporobolomyces 0.066 0.628 Cystofilobasidium 0.015 0.000 Mrakiella 0.001 0.000 Itersonilia 0.009 0.000 Udeniomyces 0.007 0.000 Filobasidium 0.283 0.919 Naganishia 0.001 0.000 Tremellomycetes Holtermanniella 0.035 0.123 Bullera 0.029 0.099 Dioszegia 0.035 0.022 Vishniacozyma 1.656 5.829 Papiliotrema 0.049 0.000 Bulleromyces 0.004 0.000 Cryptococcus 0.039 0.000 Saitozyma 0.001 0.000 Apiotrichum 0.004 0.000 Cutaneotrichosporon 0.012 0.000 Trichosporon 0.015 0.292 Urocystis 0.001 0.000 Anthracocystis 0.001 0.022 Ustilaginomycetes Moesziomyces 0.002 0.000 Pseudozyma 0.001 0.034 Wallemiomycetes Wallemia 38.822 0.004 Glomeromycetes Diversispora 0.001 0.161 Mucor 0.003 0.000 Mucoromycota Mucoromycetes Rhizopus 0.001 0.000 Neocallimastigomycetes Caecomyces 0.000 0.013 Chlorophyta Pleurastrophyceae Pleurastrum 0.123 0.425 Other 16.361 33.047 Unidentified# 0.185 10.52 *percentage share of studied genera greater than 0.001% #sequences that could not be classified into any phylogenetic group were assigned as unidentified.