This review focuses on the pyrolysis process for biochar production and its impact on the levels of polycyclic aromatic hydrocarbons (PAHs), toxic organic pollutants. PAHs are known to form during biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More pyrolysis and remain in biochar, potentially posing environmental risks. The study emphasizes the importance of optimizing pyrolysis parameters, such as temperature, residence timeResidence time refers to the duration that the biomass is heated during the pyrolysis process. The residence time can influence the properties of the biochar produced.   More, and heating rate, to minimize PAH content in biochar.

The review highlights the influence of various feedstocks and reactor designs on PAH formation. FeedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More selection, contaminated with PAHs, and improper pyrolysis protocols can significantly increase PAH levels. The interaction between pyrolysis parameters has often been overlooked, but this review addresses the gaps in understanding how these parameters collectively influence PAH content. By generating contour diagrams, the study maps the interactive effects of different parameters, providing insights into how to reduce PAH concentrations.

The findings suggest that a better understanding of these factors can guide the design of cleaner pyrolysis systems. Following international biochar production guidelines is also crucial to ensure the production of high-quality, low-toxicity biochar. The review ultimately underscores the need for systematic optimization of pyrolysis conditionsThe conditions under which pyrolysis takes place, such as temperature, heating rate, and residence time, can significantly affect the properties of the biochar produced.   More, particularly for biochar used in soil amendments, to enhance environmental safety and performance.