Airborne Fungal Exposure and Associated Respiratory Symptoms among Mushroom Farm Workers in Rural Mountainous Communities of Northern Thailand: A Cross-Sectional Study

Pornthip Yenjai; Rotruedee Chotigawin; Pattamaporn Buadaeng; Chan Pattama Polyong

doi:10.55489/njcm.170720266307

Authors

Pornthip Yenjai School of Occupational health and Safety, Institute of Public Health, Suranaree University of Technology, Nakhon Ratchasima, Thailand
Rotruedee Chotigawin Department of Environment Health, Faculty of Public Health, Burapha University, Chonburi, Thailand
Pattamaporn Buadaeng Occupational health, Safety, and Environment, Hanwha Chemical (Thailand) Co., Ltd., Samut Prakan, Thailand
Chan Pattama Polyong Occupational Health and Safety Program, Faculty of Science and Technology, Bansomdej Chaopraya Rajabhat University, Bangkok, Thailand

DOI:

https://doi.org/10.55489/njcm.170720266307

Keywords:

Airborne Fungi, Bioaerosols, Occupational Exposure, Respiratory Symptoms, Mushroom Workers, Thailand

Abstract

Background: Mushroom cultivation in humid, high-altitude rural areas of northern Thailand may expose workers to elevated levels of airborne fungi. However, quantitative evidence on fungal workplace environments and associated respiratory symptoms among mushroom workers remains limited.

Methods: A cross-sectional study not registered in a trial registry, was conducted among 350 mushroom workers from 35 rural mountain farms in northern Thailand. Workplace environmental conditions, including temperature, relative humidity, air velocity, carbon dioxide concentration, and airborne fungal counts, were measured using standardized instruments and a single-stage impactor. Worker characteristics and respiratory symptoms were collected using a structured questionnaire. Multiple logistic regression was performed to identify factors associated with upper and lower respiratory symptoms.

Results: Workers spent an average of 4.20±2.29 hours per day inside mushroom cultivation areas. Airborne fungal concentrations ranged from 515.67 to 5,708.00 CFU/m³. Upper respiratory symptoms were reported in 33.1% (n=116/350) of workers, while lower respiratory symptoms were reported in 2.6% (n=9/350). Upper respiratory symptoms were significantly associated with age 31-60 years (aOR = 2.58; 95% CI: 1.08-6.17) and fungal concentrations of 2,001-4,000 CFU/m³ (aOR = 15.03; 95% CI: 1.53-147.52). A history of respiratory disease was significantly associated with lower respiratory symptoms (aOR = 5.68; 95% CI: 1.10-31.95).

Conclusions: Airborne fungal exposure was significantly associated with respiratory symptoms, with workers exposed to fungal concentrations of 2,001-4,000 CFU/m³ showing markedly increased risk at 15.03 times. Strengthening ventilation systems and respiratory protection practices may help reduce occupational respiratory risks.

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