Abstract
Nighttime heat is an important factor in heat-health outcomes, though nighttime heat exposure and its impacts are poorly understood. We assessed overnight heat in indoor (n = 12) and outdoor (n = 3) living spaces in Knoxville, Tennessee, using iButton Hygrochrons in August 2021. Indoor sleep spaces, all of which were air conditioned, reported a variety of overnight conditions. Indoor sleep spaces were both warmer and cooler than outdoor temperatures overnight, and some participants noted having physical health effects of overnight heat in their homes. Downtown outdoor sleep spaces, including a park and encampment, exhibited an urban heat island signal, staying warmer than other outdoor areas. Future research should focus on the intensity and length of the overnight recovery period for individuals and how that affects heat-health outcomes, especially after being exposed to daytime heat. Specifically, do homes reach a cool enough temperature for recovery, and do outdoor sleeping spaces offer a long enough and cool enough period for recovery? We provide some recommendations for such future studies, including (1) focus on purposeful sampling, (2) use deliberate sensor placement for representative results, (3) prepare for participant drop-off due to non-compliance and technological problems, and (4) strategically gather demographic information.
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References
Anderson GB, Bell ML, Peng RD (2013) Methods to calculate the heat index as an exposure metric in environmental health research. Environ Health Perspect 121:1111–1119
Bailey E, Fuhrmann C, Runkle J, Stevens S, Brown M, Sugg M (2020) Wearable sensors for personal temperature exposure assessments: a comparative study. Environ Res 180. https://doi.org/10.1016/j.envres.2019.108858s
Basu R, Samet JM (2002) An exposure assessment study of ambient heat exposure in an elderly population in Baltimore, Maryland. Environ Health Persp 110:1219–1224. https://doi.org/10.1289/ehp.021101219
Bernhard MC, Kent ST, Sloan ME, Evans MB, McClure LA, Gohlke JM (2015) Measuring personal heat exposure in an urban and rural environment. Environ Res 137:410–418. https://doi.org/10.1016/j.envres.2014.11.002
Brook RD, Shin HH, Bard RL, Burnett RT, Vette A, Croghan C, Williams R (2011) Can personal exposures to higher nighttime and early-morning temperatures increase blood pressure? J Clin Hypertens 13:881–888. https://doi.org/10.1111/j.1751-7176.2011.00545.x
Clarke JF (1972) Some effects of the urban structure on heat mortality. Environ Res 5:93–104. https://doi.org/10.1016/0013-9351(72)90023-0
de Sousa T, Andrichik A, Cuellar M, Marson J, Prestera E, Rush K, Associates A (2022) The 2022 Annual homelessness assessment report (AHAR) to congress. Part 1: point-in-time estimates of homelessness. US Department of Housing and Urban Development, Washington, DC
DeGaetano AT, Allen RJ (2002) Trends in twentieth-century temperature extremes across the United States. J Climate 15:3188–3205. https://doi.org/10.1175/1520-0442(2002)015<3188:TITCTE>2.0.CO;2
Dousset B, Gourmelon F, Laaidi K, Zeghnoun A, Giraudet E, Bretin P, Mauri E, Vandentorren S (2011) Satellite monitoring of summer heat waves in the Paris metropolitan area. Int J Climatol 31:313–323. https://doi.org/10.1002/joc.2222
Ellis KN, Hathaway JM, Mason LR, Howe DA, Epps TH, Brown VM (2017) Summer temperature variability across four urban neighborhoods in Knoxville, Tennessee, USA. Theor Appl Climatol 127:701–710. https://doi.org/10.1007/s00704-015-1659-8
Franck U, Krüger M, Schwarz N, Grossmann K, Röder S, Schlink U (2013) Heat stress in urban areas: indoor and outdoor temperatures in different urban structure types and subjectively reported well-being during a heat wave in the city of Leipzig. Meteorol Z 22:167–177. https://doi.org/10.1127/0941-2948/2013/0384
Hass AL, Ellis KN (2019) Using wearable sensors to assess how a heatwave affects individual heat exposure, perceptions, and adaption methods. Int J Biometeorol 63:1585–1595. https://doi.org/10.1007/s00484-019-01770-6
Hass AL, McCanless K, Cooper W, Ellis K, Fuhrmann C, Kintziger KW, Sugg M, Runkle J (2022) Heat exposure misclassification: do current methods of classifying diurnal range in individually experienced temperatures and heat indices accurately reflect personal exposure? Int J Biometeorol 66:1339–1348. https://doi.org/10.1007/s00484-022-02280-8
Hondula DM, Kuras ER, Betzel S, Drake L, Eneboe J, Kaml M, Munoz M, Sevig M, Singh M, Ruddell B, Harlan SL (2021) Novel metrics for relating personal heat exposure to social risk factors and outdoor ambient temperature. Environ Int 146:106271. https://doi.org/10.1016/j.envint.2020.106271
Hubbart J, Link T, Campbell C, Cobos D (2005) Evaluation of a low-cost temperature measurement system for environmental applications. Hydrol Process 19:1517–1523
Kuras ER, Hondula DM, Brown-Saracino J (2015) Heterogeneity in individually experienced temperatures (IETs) within an urban neighborhood: insights from a new approach to measuring heat exposure. Int J Biometeorol 59:1363–1372. https://doi.org/10.1007/s00484-014-0946-x
Kuras ER, Richardson MB, Calkins MM, Ebi KL, Hess JJ, Kintziger KW, Jagger MA, Middel A, Scott AA, Spector JT, Uejio CK, Vanos JK, Zaitchik BF, Gohlke JM, Hondula DM (2017) Opportunities and challenges for personal heat exposure research. Environ Health Persp 125:085001. https://doi.org/10.1289/EHP556
Longo J, Kuras E, Smith H, Hondula DM, Johnston E (2017) Technology use, exposure to natural hazards, and being digitally invisible: implications for policy analytics. Policy Internet 9:76–108. https://doi.org/10.1002/poi3.144
Murage P, Hajat S, Kovats RS (2017) Effect of night-time temperatures on cause and age-specific mortality in London. Environ Epidemiol 1:e005. https://doi.org/10.1097/EE9.0000000000000005
National Weather Service (n.d.) Heat Index Calculator. https://www.wpc.ncep.noaa.gov/html/heatindex.shtml Accessed 13 November 2023
Nguyen JL, Schwartz J, Dockery DW (2014) The relationship between indoor and outdoor temperature, apparent temperature, relative humidity, and absolute humidity. Indoor Air 24:103–112. https://doi.org/10.1111/ina.12052
National Oceanic and Atmospheric Administration (n.d.) Knoxville normals and records for August. https://www.weather.gov/mrx/tysaugust Accessed 21 July 2023
Oke TR (1982) The energetic basis of the urban heat island. Q J Roy Meteor Soc 108:1–24
Powell EJ, Keim BD (2015) Trends in daily temperature and precipitation extremes for the southeastern United States: 1948–2012. J Climate 28:1592–1612. https://doi.org/10.1175/JCLI-D-14-00410.1
Rizwan AM, Dennis LY, Chunho LIU (2008) A review on the generation, determination and mitigation of Urban Heat Island. J Environ Sci 20:120–128. https://doi.org/10.1016/s1001-0742(08)60019-4
Runkle JD, Cui C, Fuhrmann C, Stevens S, Del Pinal J, Sugg MM (2019) Evaluation of wearable sensors for physiologic monitoring of individually experienced temperatures in outdoor workers in southeastern US. Environ Int 129:229–238. https://doi.org/10.1016/j.envint.2019.05.026
Schwarz L, Castillo EM, Chan TC, Brennan JJ, Sbiroli ES, Carrasco-Escobar G, Nguyen A, Clemesha RES, Gershunov A, Benmarhnia T (2022) Heat waves and emergency department visits among the homeless, San Diego, 2012–2019. Am J Public Health 112:98–106. https://doi.org/10.2105/AJPH.2021.306557
Sugg MM, Stevens S, Runkle JD (2019) Estimating personal ambient temperature in moderately cold environments for occupationally exposed populations. Environ Res 173:497–507. https://doi.org/10.1016/j.envres.2019.03.066
Sugg MM, Runkle JD, Dow K, Barnes J, Stevens S, Pearce J, Bossk B, Curtis S (2022) Individually experienced heat index in a coastal Southeastern US city among an occupationally exposed population. Int J Biometeorol 66:1665–1681. https://doi.org/10.1007/s00484-022-02309-y
Tartarini F, Cooper P, Fleming R, Batterham M (2017) Indoor air temperature and agitation of nursing home residents with dementia. Am J Alzheimers Dis Other Demen 32:272–281. https://doi.org/10.1177/1533317517704898
Tuholske C, Caylor K, Funk C, Verdin A, Sweeney S, Grace K, Peterson P, Evans T (2021) Global urban population exposure to extreme heat. PNAS 118:e2024792118. https://doi.org/10.1073/pnas.2024792118
Uejio CK, Wilhelmi OV, Golden JS, Mills DM, Gulino SP, Samenow JP (2011) Intra-urban societal vulnerability to extreme heat: the role of heat exposure and the built environment, socioeconomics, and neighborhood stability. Health Place 17:498–507. https://doi.org/10.1016/j.healthplace.2010.12.005
Uejio CK, Morano LH, Jung J, Kintziger K, Jagger M, Chalmers J, Holmes T (2018) Occupational heat exposure among municipal workers. Int Arch Occ Env Hea 91:705–715. https://doi.org/10.1007/s00420-018-1318-3
Wang S, Wu CY, Richardson MB, Zaitchik BF, Gohlke JM (2021) Characterization of heat index experienced by individuals residing in urban and rural settings. J Expo Sci Env Epid 31:641–653. https://doi.org/10.1038/s41370-021-00303-x
Yip FY, Flanders WD, Wolkin A, Engelthaler D, Humble D, Neri A, Lewis L, Backer L, Rubin C (2008) The impact of excess heat events in Maricopa County, Arizona: 2000–2005. Int J Biometeorol 52:765–772. https://doi.org/10.1007/s00484-008-0169-0
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This work was funded by the Institute for a Secure and Sustainable Environment at the University of Tennessee.
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Ellis, K.N., First, J.M., Kintziger, K.W. et al. Overnight heat in sleep spaces of housed and unhoused residents: results and recommendations from a Knoxville, Tennessee, case study. Int J Biometeorol 68, 637–646 (2024). https://doi.org/10.1007/s00484-023-02611-3
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DOI: https://doi.org/10.1007/s00484-023-02611-3