22 Present address: 1 ICAR-Indian Agricultural Research Institute, New Delhi. *Corresponding author e-mail: adarsh_iari@ rediffmail.com. Indian Journal of Agricultural Sciences 91 (5): 678–82, May 2021/Article Particulate matter exposure of combine harvester operator during wheat harvesting in northern India UTPAL EKKA 1 , ADARSH KUMAR 1 * and HIMADRI SEKHAR ROY 1 ICAR-Indian Agricultural Research Institute, New Delhi 110 012, India Received: 28 August 2019; Accepted: 05 January 2021 ABSTRACT A study was carried out to assess the quantum of particulate matter in the breathing zone and workspace of combine harvester operator during 2018-19 in wheat felds of ICAR-Indian Agricultural Research Institute, New Delhi. Mass concentration and particle size distribution of dust were assessed in the breathing zone for different size fractions related to health during wheat harvesting using a personal dust monitor. Sticky papers were used to determine the characteristics of particulate matter and wheat straw (>100 µm) in the workspace of the combine harvester. The average mass concentration of inhalable, thoracic and respirable particles were 9500, 4150 and 940 µg/m 3 and PM 10, PM 2.5 and PM 1 particles were 3722, 453 and 120 µg/m 3 in the breathing zone. Particulate matter concentrations were 37 and 8 times (daily basis) and 62 and 11 times (annual basis) higher than the permissible value of PM 10 and PM 2.5 . The equivalent diameter of wheat straw ranged up to 1400 µm with a density of 9-12 particles per mm 2 surface area. It amounts to 1.2 million particles in the workspace with the potential of sticking on exposed body of the operator considering a 10% body surface area. Keywords: Combine harvester operator, Dust exposure, Particulate matter, Working environment, Wheat straw The present population of combine harvester in India is 40000, with an addition of 5000 every year (Mehta et al. 2019). Combine harvesting of wheat produces a large amount of particulate matters (PM) on farm. The increased number of combine harvester employs a large number of operators.In low-income countries, operators are exposed to dust and other harsh environmental conditions as combines are not equipped with cabins, unlike developed nations. Operators are exposed to particulate matter and wheat straw during harvesting and threshing (Pandirwar et al. 2014). Due to the small window of the wheat harvesting period, the operator has to work for a long duration, even at night, consequently increasing the dust inhalation and ill effects of straw particles on the exposed body of the operators. In developed countries, cabins are installed on a combine harvester, which prevents dust exposure, results in a reduction of dust from 2 to 20 μg/m 3 to 0.1 to 1 μg/m 3 by air fltration (Kirkhorn and Garry 2000) and restriction of dust movement (Zander 1972). Exposure to dust and straw in high temperatures and dry weather with low relative humidity cause health problems (EPA 2019) along with operational diffculties. Particulate matter less than 10 μm generated during agricultural operations constituting of PM 2.5 and PM 1.0 (Chen et al. 2016). PM 10 produced during agricultural operations are most likely to cause ill health; however, particulate matter less than 2.5 µm (PM 2.5 ) penetrates the gas exchange regions of the lungs (Arslan et al. 2010) and adversely affects the bloodstream. Agricultural dust also carries harmful bacteria, fungal spores, mould spores, pesticide residues, endotoxins and mycotoxins (HSE 2007). Inhalation of grain dust is responsible for releasing histamine and leukotrienes from lung tissues, which may cause of acute broncho constriction among farmers (Behera et al. 2005). Other detrimental effects of dust exposure are infammation of the eyes, lungs, and skin.Very few studies have been conducted on dust and wheat straw exposure of combine harvester operators in developing countries. The present study is conducted to assess the dust in the breathing zone and workspace of the combine harvester operator during wheat harvesting. MATERIALS AND METHODS Exposure assessments: Experiments were conducted for two consecutive years (2018 and 2019) at ICAR-IARI, New Delhi experimental farms on combine harvester without cabin for assessing the mass concentration (µg/m 3 ) of inhalable particulate matter including thoracic, respirable, https://doi.org/10.56093/ijas.v91i5.112982