Aerobiological Profile of Tea Gardens in Northeastern Himalayan Regions in India and Its Association with Respiratory Allergy Among Tea Workers: A Comprehensive Technical and Clinical Synthesis

Tea plantations of the Northeastern Himalayan region of India represent major tea-producing landscapes and support a large workforce. Their warm, humid climate, dense vegetation, and intensive processing activities generate diverse bioaerosols, including pollen, fungal spores, bacteria, and organic dust, with potential occupational respiratory health implications. This review synthesizes evidence on the aerobiological characteristics of tea-growing ecosystems and their association with respiratory allergy and other occupational respiratory disorders among tea workers. Literature from India and other major tea-producing regions was critically evaluated, focusing on the diversity, seasonal dynamics, and environmental determinants of airborne pollen and fungal spores, particularly in Assam, Darjeeling, Dooars, Terai, and adjoining Himalayan tea-growing areas. Fungal genera including Cladosporium, Aspergillus, Penicillium, Alternaria, and Curvularia, along with allergenic pollen from grasses, weeds, and surrounding vegetation, frequently constitute important components of the bioaerosol burden. Their abundance varies with temperature, humidity, rainfall, wind, and seasonal vegetation. Processing environments may further increase exposure through respirable tea dust and “tea fluff.” Available evidence from tea-worker studies indicates respiratory symptoms, ventilatory impairment, and allergic or sensitization responses associated with occupational tea-related exposures. However, direct evidence linking specific airborne pollen or fungal taxa detected in tea-growing environments to specific respiratory outcomes in tea workers remains limited. The available literature therefore supports a distinction between direct aerobiological observations, occupational exposure evidence, and clinical evidence, rather than assuming a direct exposure–disease relationship and highlights the need for standardized monitoring, respiratory health surveillance, engineering controls, and evidence-based workplace policies.