Airborne impacts to humans working with plastic recycled construction bricks

Over 9.2 billion metric tons of plastic were manufactured between 1950 and 2017, and the world continues to produce >400 million metric tons annually. Waste management systems available to cope with the mounting burden of plastic waste include landfills, incineration, and recycling. Emerging technologies have also focused on the incorporation of recycled plastic waste into construction materials as an alternative with several benefits. Purchasing plastic from municipal waste sites or collecting plastic garbage from the environment is cost effective, making plastic bricks an inexpensive alternative to traditional construction materials, a cost-effective way to confront pollution, and a simple approach for local communities to access needed building supplies. The research objectives in this proposal will integrate work in both exposure assessment and health effects in order to provide a comprehensive understanding of environmental emissions and leaching from recycled-plastic bricks/pavers across their life cycle (from production, to use and weathering). The first approach will investigate the physiochemical nature of both gas-phase and particulate emissions released during brick production and the effects of recycled plastic weathering on the emission profiles. The second approach will investigate the capacity for grinding/cutting of these bricks, common techniques employed during construction, to produce inhalable microplastics/nanoplastics (MPs/NPs) and promote the release of encapsulated toxins/additives. In our final approach, a ventilated artificial lung exposure system will assess intrapulmonary exposure conditions and the impact of repeated exposure to these aerosolized pollutants on primary human airway epithelium grown under air-liquid-interface (ALI) conditions. Assays will assess acute toxicity, impact on inflammatory and growth factors, and detailed alterations to the transcriptome by differential mRNA-Seq and gene functional pathway analyses. Specialized techniques previously developed for analyzing engineered nanomaterials (ENMs) and the toxicology of inhaled tobacco products will be applied in novel ways to the study of recycled plastic products. Our multidisciplinary team includes an environmental health and aerosol scientist, an environmental engineer, and a pulmonologist with expertise in environmental and molecular toxicology. Working together, we will determine the exposure potential from plastic recycling and construction brick production in Aim 1, the impact of construction practices (such as grinding) on aerosol release in Aim 2, and intrapulmonary exposure conditions and biologic effects from recycled plastic exposures in Aim 3. This will allow us to carefully investigate emissions, exposures and potential health effects across the life cycle of these recycled-plastic construction bricks/paver. We will focus on hydrophobic polyethylene terephthalate (PET) and high-density polyethylene (HDPE) plastics; the principle recycled plastics in the U.S. Emissions of particulate matter (PM) containing MPs and NPs, volatile organic compounds (VOCs), heavy metal, and metal oxides will be measured. Project Number: 1R01ES038127-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Environmental Health Sciences (NIEHS) | Principal Investigator: Candace SuJung Tsai | Institution: UNIVERSITY OF CALIFORNIA LOS ANGELES, LOS ANGELES, CA | Award Amount: $743,900 | Activity Code: R01 | Study Section: Environmental Determinants of Disease Study Section [EDD] View on NIH RePORTER: https://reporter.nih.gov/project-details/11274276