Chemical emissions from building materials may significantly impact indoor air quality and potentially human health, since individuals spend most of their time indoors. With rising global temperatures and more frequent heatwaves, building materials’ resilience becomes more crucial for indoor air quality and structural integrity. However, the effects of temperature rise on building material emissions are not systematically studied. This study investigates the effect of a moderate temperature rise on the volatile organic compound (VOC) and aldehyde emissions of eighteen commonly used building materials, such as engineered hardwood, nylon carpet, terrazzo flooring, and acoustic tile, at two elevated yet realistic temperature points. The chemical emissions were collected using a micro-chamber setup and analyzed using thermal desorption/gas chromatography/mass spectrometry and high-performance liquid chromatography. The results showed that 78% of the materials tested demonstrated increased chemical emissions at higher temperatures. Wood-flooring materials showed statistically significant increases in formaldehyde at elevated temperatures, which could be associated with health risks. Eight of the tested materials, particularly those used in large surface area applications, showed significant increases in emissions at increased temperatures, and half of these were labeled as “low-VOC”. These findings may inform the updating of building standards and third-party certification with respect to temperature variation when assessing building material emissions. This research aims to provide a comprehensive understanding of VOC and aldehyde emissions at emerging indoor environmental conditions due to extreme heat climate scenarios.

The wildland-urban interface (WUI) fires have adverse effects on both physical and mental health. However, early biosignals changes related to fires are not well understood. Digital wearables can capture real-time changes in physiological stress and activity patterns, providing insight into the mechanisms of health effects of WUI fires and identifying vulnerable populations during and after WUI fires. This study aimed to assess the immediate and sustained changes in physical activity patterns and physiological stress markers during and after the 2025 Los Angeles Wildfires. We conducted a longitudinal study of 15 older adults (mean age 73.2 years) during the 2025 Eaton Fire in Los Angeles, using the digital Oura Ring (Gen 3) continuously. Data were collected at baseline (Dec 9th, 2024 to Jan 6th, 2025), during the fire (Jan 7th to Jan 12th, 2025), and after the fire (Jan 13th to Jan 27th, 2025). Daily activity patterns (physical activity and sleep duration) and physiological stress (sleep heart rate, heart rate variability, sleep fragmentation, and breath rate) were collected, and linear mixed-effects models were used to investigate how these biosignals changed and how evacuation alerts impacted these changes. During the fire, six out of fifteen participants received evacuation alerts. We observed a 41-minute increase in sedentary time (P =.007), a 34-minute reduction in sleep duration (P =.002), and a 0.4 BPM increase in sleep breath rate (P =.009). Although activity patterns returned to baseline post-fire, markers of physiological stress, including sleep heart rate and breath rate, remained elevated. Among participants who received evacuation alerts, the immediate and prolonged impacts are larger. The changes in activity patterns and increases in physiological stress during and after the 2025 Los Angeles wildfire in this cohort can indicate potential health effects. Digital bio-signals may serve as early indicators of adverse health outcomes following a wildfire.