Combine harvesters have made harvesting faster across India's agricultural regions, but the dust generated during their operation could pose a significant occupational health risk to workers.
A 2021 study found high concentrations of airborne particles in the breathing zone of combine harvester operators during wheat harvesting in northern India, prompting questions about the long-term effects on their respiratory health.
The findings assume significance as the Indian Council of Medical Research (ICMR) has invited research institutions to investigate dust exposure among combine harvester operators and helpers and develop affordable ways to protect their lungs.
The study, published in the Indian Journal of Agricultural Sciences, was conducted by Utpal Ekka, Adarsh Kumar and Himadri Sekhar Roy of the ICAR-Indian Agricultural Research Institute (IARI), New Delhi. It assessed exposure during the 2018-19 wheat harvesting season.
Researchers recorded an average inhalable particulate matter concentration of 9,500 micrograms per cubic metre in the operators' breathing zone. The average concentration of thoracic particles was 4,150 micrograms per cubic metre, while respirable particles measured 940 micrograms per cubic metre.
The study also recorded average concentrations of 3,722 micrograms per cubic metre for PM10, 453 micrograms per cubic metre for PM2.5 and 120 micrograms per cubic metre for PM1. Fine particles are of particular concern because they can penetrate deeper into the respiratory system.
However, the study focused on measuring airborne particulate matter and did not establish the prevalence of respiratory diseases among operators or the long-term consequences of repeated exposure. It was also limited to wheat harvesting in northern India, leaving unanswered questions about exposure across different crops, regions and harvesting conditions.
Addressing this gap, ICMR is seeking research proposals to assess occupational dust exposure and its effects on the respiratory health of combine harvester workers across agricultural regions, said a scientist with the ICMR.
The research will be undertaken under the SEHAT Mission (Science Excellence for Health through Agricultural Transformation), a joint initiative of ICMR and the Indian Council of Agricultural Research (ICAR). The programme aims to strengthen research linking agriculture, nutrition and health.
According to the scientist, operators and helpers, many of whom are seasonal migrant workers, often work long hours on machines with open platforms. During harvesting, they are exposed to a mixture of crop and straw dust, fungal spores, bacterial toxins and fine soil particles.
Repeated exposure could increase the risk of respiratory conditions such as chronic bronchitis, occupational asthma and chronic obstructive pulmonary disease (COPD). Some workers may also develop hypersensitivity pneumonitis, an inflammatory lung condition that can cause permanent damage in severe cases, noted the scientist.
The consequences may extend beyond health, affecting workers' ability to earn a livelihood, particularly during the peak harvesting season when they depend on sustained employment.
The proposed research will measure inhalable and respirable dust concentrations, assess respiratory symptoms and examine lung function through spirometry. It will also evaluate whether exposure varies according to crop type, geographical region, machine design and harvesting season.
ICMR is particularly interested in practical, low-cost engineering solutions. These include retrofitting open-platform harvesters with enclosed operator cabins fitted with air filters. Such cabins could maintain filtered air under positive pressure to prevent dust from entering.
Other possible interventions include modifying machine components to reduce dust generation, providing appropriate masks and protective goggles, and installing affordable sensors to monitor dust levels and alert workers when exposure rises.
Researchers will also examine safer operating and maintenance practices, including filter cleaning, grain unloading and machine positioning. An important part of the assessment will be whether protective equipment is comfortable enough to be used consistently during long shifts in hot weather.
Multidisciplinary research involving agricultural engineers, occupational health specialists, respiratory physicians, epidemiologists and public health researchers have been invited to conduct the study, he said. Partnerships with farm machinery manufacturers, agricultural universities, testing institutes and state agriculture departments are also encouraged.
Apart from measuring health outcomes, the projects will assess the cost, durability and acceptability of proposed interventions. The findings could help establish technical standards for air quality inside harvester cabins and support the inclusion of protective modifications in existing farm mechanisation subsidy programmes. Projects can run for three to five years, with funding of up to Rs 8 crore.
The 2021 study provides an important baseline for the proposed investigation. While it established that operators can face substantial particulate exposure during harvesting, the new research is expected to determine how this translates into respiratory risks and which affordable interventions can work under Indian farming conditions.
