Are Particulate Pollutants Emitted by Open-Burning of Agricultural Plastic Waste (Greenhouse LDPE Film) Harmful?

Abstract

Background and objective: Agricultural plastic waste (APW), which includes various types of plastics and greenhouse film, accounts for the largest volume of annual average incineration of plastic (Korea Environment Corporation, 2021). Open-burning incineration of such APW emits metallic particulate pollutants, the human hazard of which is widely known. As such, the systematic management of incinerable APW is required. Furthermore, basic physicochemical research on particulate pollutants (PPs) is needed for related policy decision-making.Methods: The U.S. EPA particulate test method (Method 5G) was applied to set up the experimental infrastructure for an open-air incineration simulation. Scanning electron microscopes with SEM-EDS and XRF were used for a chemical species analysis of the generated particulate matter (PM). Low-density polyethylene (LDPE), used as a greenhouse material and collected by the Dangjin plastic collection office of the Korea Environment Corporation, was used as samples and subjected to incineration test three times.Results: Chemical speciation by an XRF analysis showed that the major chemical components of LDPE before incineration, listed in order of their content, were Fe (26.87%, SD = 20.67) > Si (25.91%, SD = 11.29) > Al (16.43%, SD = 7.23), which was changed to Si (44.51%, SD = 0.25) > Zn (16.53%, SD = 0.03) > Ba (15.73%, SD = 0.05) after incineration. An SEM-EDS analysis found the PM emitted as rock-like shapes and cotton-like shapes. Regarding the weight ratio, the rock-shaped particles contained less C (8.94 wt%, SD = 1.90) and more Al (11.77 wt%, SD = 3.08) and Fe (9.58 wt%, SD = 7.14), whereas the cotton-shaped particles contained more C (29.44 wt%, SD = 3.97), less Al (2.34 wt%, SD = 0.19), and an untraceable amount of Fe (ND).Conclusion: This study found that PPs emitted through the incineration of APW such as LDPE can be classified into rock-like shapes and cotton-like shapes, which is related to the difference in weight ratio of non-metals (C), transition metals (Fe), and other metals (Al) in unit particulate matter.