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The increasing prevalence of hazardous chemical incidents in the United States necessitates the implementation of analytically robust, rapid, and reliable screening techniques for toxicant mixture analysis to understand short- and long-term health impacts of environmental exposures. A recent chemical disaster in East Palestine, Ohio has underscored the importance of thorough contamination assessment. On February 03, 2023, a Norfolk Southern train derailment prompted a chemical spill and fires. An open burn involving over 100,000 gal of vinyl chloride was conducted three days later. Hazardous compounds were released into air, water, and soil. To provide time-sensitive exposure data for emergency response, this study outlines a novel methodology for rapid characterization of chemical contamination of environmental media to support disaster response efforts. A controlled static headspace sampling system, in conjunction with a high-resolution proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS), was developed to characterize volatile organic compounds (VOCs) in surface water samples collected near the East Palestine train derailment site. Spatial variations were observed in the chemical composition of surface water samples collected at different locations. Hydrocarbons were found to be the most abundant chemical group of all surface water samples, contributing 50 % to 97 % to the total headspace VOC mass. Compounds commonly detected in surface water samples, including benzene, styrene, xylene, and methyl tert-butyl ether (MTBE) were also observed in most surface water samples, with aqueous concentrations typically at ng/L levels. This study demonstrated the potential of the proposed methodology to be applied for rapid field screening of volatile chemicals in water samples in order to enable fast emergency response to chemical disasters and environmental hazards. 

Nanocluster aerosol (NCA: particles in the size range of 1–3 nm) are a critically important, yet understudied, class of atmospheric aerosol particles. NCA efficiently deposit in the human respiratory system and can translocate to vital organs. Due to their high surface area-to-mass ratios, NCA are associated with a heightened propensity for bioactivity and toxicity. Despite the human health relevance of NCA, little is known regarding the prevalence of NCA in indoor environments where people spend the majority of their time. In this study, we quantify the formation and transformation of indoor atmospheric NCA down to 1 nm via high-resolution online nanoparticle measurements during propane gas cooking in a residential building. We observed a substantial pool of sub-1.5 nm NCA in the indoor atmosphere during cooking periods, with aerosol number concentrations often dominated by the newly formed NCA. Indoor atmospheric NCA emission factors can reach up to ~10^16 NCA/kg-fuel during propane gas cooking and can exceed those for vehicles with gasoline and diesel engines. Such high emissions of combustion-derived indoor NCA can result in substantial NCA respiratory exposures and dose rates for children and adults, significantly exceeding that for outdoor traffic-associated NCA. Combustion-derived indoor NCA undergo unique size-dependent physical transformations, strongly influenced by particle coagulation and condensation of low-volatility cooking vapors. We show that indoor atmospheric NCA need to be measured directly and cannot be predicted using conventional indoor air pollution markers such as PM2.5 mass concentrations and NOx (NO + NO2) mixing ratios. 

Scented wax products, such as candles and wax warmers/melts, are popular fragranced consumer products that are commonly used in residential buildings. As scented wax products are intentionally fragranced to produce pleasant smellscapes for occupants, they may represent an important source of volatile organic compounds (VOCs) to indoor atmospheres. The aim of this study is to evaluate terpene emission factors (EFs) and inhalation intake fractions (iFs) for scented wax products to better understand their impact on indoor chemistry and chemical exposures. Full-scale emission experiments were conducted in the Purdue zEDGE Test House using a variety of scented candles (n = 5) and wax warmers/melts (n = 14) under different outdoor air exchange rates (AERs). Terpene concentrations were measured in real-time using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). PTR-TOF-MS measurements revealed that scented candle and wax warmer/melt products emit a variety of monoterpenes (C10H16) and oxygen-containing monoterpenoids (C10H14O, C10H16O, C10H18O, C10H20O), with peak concentrations in the range of 10^−1 to 10^2 ppb. Monoterpene EFs were much greater for scented wax warmers/melts (C10H16 EFs ~ 10^2 mg per g wax consumed) compared to scented candles (C10H16 EFs ~ 10^−1 to 100 mg per g wax consumed). Significant emissions of reactive terpenes from both products, along with nitrogen oxides (NO, NO2) from candles, depleted indoor ozone (O3) concentrations. Terpene iFs were similar between the two products (iFs ~ 10^3 ppm) and increased with decreasing outdoor AER. Terpene iFs during concentration decay periods were similar to, or greater than, iFs during active emission periods for outdoor AERs ≤ 3.0 h^−1. Overall, scented wax warmers/melts were found to release greater quantities of monoterpenes compared to other fragranced consumer products used in the home, including botanical disinfectants, hair care products, air fresheners, and scented sprays.