  Citation: Kanageswari, S.V.; Tabil, L.G.; Sokhansanj, S. Dust and Particulate Matter Generated during Handling and Pelletization of Herbaceous Biomass: A Review. Energies 2022, 15, 2634. https:// doi.org/10.3390/en15072634 Academic Editor: Alberto-Jesus Perea-Moreno Received: 2 February 2022 Accepted: 24 March 2022 Published: 4 April 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Review Dust and Particulate Matter Generated during Handling and Pelletization of Herbaceous Biomass: A Review Singara Veloo Kanageswari 1 , Lope G. Tabil 2, * and Shahabaddine Sokhansanj 1,2 1 Biomass and Bioenergy Research Group, Department of Chemical and Biological Engineering, University of British Columbia, 2360 E Mall, Vancouver, BC V6T 1Z3, Canada; kanages3@mail.ubc.ca (S.V.K.); shahab.sokhansanj@ubc.ca (S.S.) 2 Chemical and Biological Department, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada * Correspondence: lope.tabil@usask.ca Abstract: Using straw and herbaceous crops to replace or augment fossil fuels is becoming popular as access to forest biomass becomes environmentally stricter and more expensive. The low bulk density raw biomass is pre-processed and densified into pellets to facilitate handling and use. Dust is generated during collection, baling and debaling, grinding, drying, and densifying processed herbaceous biomass. Abundant literature deals with dust generated during the industrial handling of woody biomass, grains, and other crops like cotton. But the information on handling herbaceous biomass in the open literature is scarce. This paper reviews the available literature on dust gen- eration from handling and processing of herbaceous biomass. Limited available data shows that herbaceous biomass species have a lower ignition temperature than woody biomass. The paper identifies several crucial pieces of information needed to ensure safety in the handling and pelleting of herbaceous crops. Keywords: biomass fuel pellet; pellet production; dust generation; densification; particulate emission 1. Introduction The increase in global demand for pellets and the limited availability of wood re- sources shift the focus towards herbaceous biomass utilization and strategies to promote herbaceous biomass pelletization technology. Many researchers experimented with numer- ous feedstocks to produce high-quality pellets from herbaceous biomass, as summed up by Stelte et al. [1], showing enormous interest in this sector. A recent joint study by Agriculture and Agri-Food Canada (AAFC) and Natural Resources Canada (NRCan) [2] estimates the annual agricultural biomass produced in Canada at 80 Mt (million oven dry Mg). This number includes approximately 50 Mt of grains/seeds and about 30 Mt of crop residue. Roughly 71 Mt of annual forestry residue and 9.4 Mt of municipal waste can also be included in the inventory of biomass in Canada [2]. Wheat and barley are grown in all agricultural areas of Canada. Corn has a high yield and is primarily grown in Ontario and Quebec. Moving the industry forward by producing pellets from excess crop residue provides additional income for the farmer. Storage and handling of a pelletized biomass are much more accessible, safer, and cheaper than the activities for other forms of solid biomass. After harvest, herbaceous biomass is baled and transported to a pellet plant where mul- tiple steps take place: bale receiving, drying, grinding, pelletization, cooling and screening, packing and storage. The block diagram in Figure 1 shows the flow of herbaceous biomass from the field to the pellet plant. Dust is generated at every step of the process leading to the gradual accumulation of dust on the ceiling and other parts of the infrastructure and equipment, forming a dust layer. In 1997, measurements conducted on three alfalfa dehydrating plants in Alberta indicated that they emitted particulate matter at higher than Energies 2022, 15, 2634. https://doi.org/10.3390/en15072634 https://www.mdpi.com/journal/energies