The contribution of physical exertion to heat-related illness and death in the Arizona borderlands.

Recent studies and reports suggest an increased mortality rate of undocumented border crossers (UBCs) in Arizona is the result of heat extremes and climatic change. Conversely, others have shown that deaths have occurred in cooler environments than in previous years. We hypothesized that human locomotion plays a greater role in heat-related mortality and that such events are not simply the result of exposure. To test our hypothesis, we used a postmortem geographic application of the human heat balance equation for 2,746 UBC deaths between 1990 and 2022 and performed regression and cluster analyses to assess the impacts of ambient temperature and exertion. Results demonstrate exertion having greater explaining power, suggesting that heat-related mortality among UBCs is not simply a function of extreme temperatures, but more so a result of the required physical exertion. Additionally, the power of these variables is not static but changes with place, time, and policy.

Greening Up For Mosquitoes: A Comparison of Green Stormwater Infrastructure in a Semiarid Region.

Green stormwater infrastructure provides environmental, economic, and health benefits as a strategy for building resilience against climate change impacts. However, it may inadvertently increase vulnerability due to improper design and construction or lack of maintenance. We engaged city stakeholders and a diverse student group to investigate possible maladaptation. After rain events, student interns collected data at green stormwater infrastructure, identified in partnership with city stakeholders, for both water retention and mosquito larvae, if present. During the sampling period in 2018, 24 rain events occurred, with 28 sites visited 212 times including visits to basins (63%), curb cuts (34%), and a bioswale (2%). The largest basin consistently retained water (mean: 3.3 days, SD: 2.3 days) and was a positive site for Culex quinquefasciatus, a West Nile virus vector. We found that while basins can become mosquito breeding habitat, there was no evidence that curb cuts were collecting and retaining water long enough. As cities turn to green stormwater infrastructure to address climate change impacts of increasing drought, flooding, and extreme heat, these findings can help in the selection of appropriate infrastructure design typologies.

Extreme heat at outdoor COVID-19 vaccination sites.

Extreme heat is an increasing climate risk due to climate change and the urban heat island (UHI) effect and can jeopardize points of dispensing (PODs) for COVID-19 vaccination distribution and broader public health emergency preparedness (PHEP) response operations. These PODs were often located on large parking lot sites with high heat severity and did not take heat mitigation or management strategies into account for unacclimated workers and volunteers. To investigate the personal heat exposure of workers, volunteers, and clients at three PODs in Tucson, Arizona, we collected ambient air temperatures, wet bulb globe temperatures (WBGT), surface temperatures, and thermal images. We also made qualitative observations and compared data against daily meteorological records. Ambient air temperatures at all three PODs exceeded the meteorological recorded high. WBGT on average were 8°F (4.4 °C) higher in full sun locations than shaded locations such as tents. Evaporative cooling decreased ambient air temperatures by 2°F (1.2 °C) when placed one per tent, but decreased ambient air temperatures by 7°F (3.9 °C) when placed en masse in a larger tent. Vehicle surface temperatures exceeded recommended safe limits of 140°F (60 °C) at all three sites, with a maximum temperature recorded at 170.9°F (77.2 °C). Public health professionals should consider heat resilience, including heat mitigation and management measures, in POD and PHEP response operations to reduce exposure. This includes considering the UHI effect in the siting of PODs, applying heat mitigation strategies in the design of PODs such as the adaptive use of solar panels for shading, and improving heat safety guidance for workers and volunteers.