Airborne fungi are considered important causes of respiratory allergy and diseases. The knowledge of these fungi in a city or region is important for the ecological diagnosis and specific treatment of respiratory manifestations induced by inhalation of fungal agents. Therefore, in recent years bioaerosols and their density in the air is highly regarded. Identifying fungi with common mycological methods as well as molecular about 5% of people are prone to allergic symptoms of the respiratory tract caused by molds during their lives. Fungi are being considered as one of the most common triggers of asthma, allergic rhinitis and other respiratory problems.

We aimed at the investigation of the airborne fungi of Ahvaz, Khuzestan province, Iran, during spring and autumn months.

A total of 224 Petri dishes with Sabouraud dextrose agar medium containing chloramphenicol were exposed at seven different regions in the city. Two hundred and twenty-four samples (112 samples per season) were taken from outdoor air seven areas of Ahvaz using microbial sampler (Quick Take-30, SKC, USA) with Debbi 14.3L/min during 5minutes directly on Sabouraud dextrose agar medium with Chloramphenicol and Dechlorane. The effects of environmental factors such as temperature, humidity and wind velocity on bioaerosol concentrations were studied.

The dishes exposed yielded 1240 fungal colonies of 24 genera. The most predominant were: Cladosporium spp. (37.1%), Alternaria spp. (25.7%), Aspergillus spp. (13.5%), Penicillium spp. (5.9%), Drechslera spp. (3.46%) and Stemphylium spp. (3.46%). The maximum and minimum numbers of airborne fungi were isolated from humid (32.3%) and industrial (17%) environments, respectively. In addition, positive correlation was observed between the number of fungi and relative humidity (r=0.476, P=0.000) in spring and autumn seasons.

This study indicated that the incidence of airborne fungi with clinical significance had a direct relationship with the variation of environmental conditions.