Abstract
The health consequences of heat and cold are usually evaluated based on associations with outdoor measurements collected at a nearby weather reporting station. However, people in the developed world spend little time outdoors, especially during extreme temperature events. We examined the association between indoor and outdoor temperature and humidity in a range of climates. We measured indoor temperature, apparent temperature, relative humidity, dew point, and specific humidity (a measure of moisture content in air) for one calendar year (2012) in a convenience sample of eight diverse locations ranging from the equatorial region (10 °N) to the Arctic (64 °N). We then compared the indoor conditions to outdoor values recorded at the nearest airport weather station. We found that the shape of the indoor-to-outdoor temperature and humidity relationships varied across seasons and locations. Indoor temperatures showed little variation across season and location. There was large variation in indoor relative humidity between seasons and between locations which was independent of outdoor airport measurements. On the other hand, indoor specific humidity, and to a lesser extent dew point, tracked with outdoor, airport measurements both seasonally and between climates, across a wide range of outdoor temperatures. These results suggest that, in general, outdoor measures of actual moisture content in air better capture indoor conditions than outdoor temperature and relative humidity. Therefore, in studies where water vapor is among the parameters of interest for examining weather-related health effects, outdoor measurements of actual moisture content can be more reliably used as a proxy for indoor exposure than the more commonly examined variables of temperature and relative humidity.
Similar content being viewed by others
References
American Community Survey. United States Census Bureau Physical housing characteristics for occupied housing units, 2013 American Community Survey 1-year estimates. http://www.census.gov/acs/www/, Accessed 1/24/2015
American Housing Survey. United States Census Bureau National summary tables—AHS 2013. http://www.census.gov/programs-surveys/ahs/data/2013/national-summary-report-and-tables---ahs-2013.html, Accessed 1/24/2015
Anderson BG, Bell ML (2009) Weather-related mortality: how heat, cold, and heat waves affect mortality in the United States. Epidemiology 20:205–213
Barnett AG, Astrom C (2012) Commentary: what measure of temperature is the best predictor of mortality? Environ Res 118:149–151
Basu R (2009) High ambient temperature and mortality: a review of epidemiologic studies from 2001 to 2008. Environ Heal 8:40. doi:10.1186/1476-069X-8-40
Bhaskaran K, Hajat S, Haines A, Herrett E, Wilkinson P, Smeeth L (2009) Effects of ambient temperature on the incidence of myocardial infarction. Heart 95:1760–1769
Braga AL, Zanobetti A, Schwartz J (2002) The effect of weather on respiratory and cardiovascular deaths in 12 U.S. cities. Environ Health Perspect 110:859–863
Byers HR (1959) General meteorology, 3rd edn. McGraw-Hill, New York
Castellani JW, M Brenner IK, Rhind SG (2002) Cold exposure: human immune responses and intracellular cytokine expression. Med Sci Sports Exerc 34:2013–2020
Collins KJ (1986) Low indoor temperatures and morbidity in the elderly. Age Ageing 15:212–220
Givoni B, Belding HS (1962) The cooling efficiency of sweat evaporation. In: Tromp SW (ed) Biometeorology: proceedings of the second international bioclimatological congress. Pergamon Press, London
Healy JD (2003) Excess winter mortality in Europe: a cross country analysis identifying key risk factors. J Epidemiol Community Health 57:784–789
Höppe P, Martinac I (1998) Indoor climate and air quality. Review of current and future topics in the field of ISB study group 10. Int J Biometeorol 42:1–7
Keatinge WR (2002) Winter mortality and its causes. Int J Circumpol Health 61:292–299
Koskela HO (2007) Cold air-provoked respiratory symptoms: the mechanisms and management. Int J Circumpol Health 66:91–100
Larsson K, Tornling G, Gavhed D, Muller-Suur C, Palmberg L (1998) Inhalation of cold air increases the number of inflammatory cells in the lungs in healthy subjects. Eur Respir J 12:825–830
Mavrogianni A, Wilkinson P, Davies M, Biddulph P, Oikonomou E (2012) Building characteristics as determinants of propensity to high indoor summer temperatures in London dwellings. Build Environ 55:117–130
Medina-Ramon M, Schwartz J (2007) Temperature, temperature extremes, and mortality: a study of acclimatization and effect modification in 50 United States cities. Occup Environ Med 64:827–833
National Weather Service. Weather Prediction Center. The heat index equation. http://www.hpc.ncep.noaa.gov/html/heatindex_equation.shtml, Accessed 10/3/2014
Nguyen JL, Schwartz J, Dockery D (2014) The relationship between indoor and outdoor temperature, apparent temperature, relative humidity, and absolute humidity. Indoor Air 24:103–112
Ostro B, Rauch S, Green R, Malig B, Basu R (2010) The effects of temperature and use of air conditioning on hospitalizations. Am J Epidemiol 172:1053–1061
Reinikainen LM, Jaakkola JJ (2003) Significance of humidity and temperature on skin and upper airway symptoms. Indoor Air 13:344–352
Saucier WJ (2003) Principles of meteorological analysis. Dover Publications, Mineola
Shaman J, Pitzer VE, Viboud C, Grenfell BT, Lipsitch M (2010) Absolute humidity and the seasonal onset of influenza in the continental United States. PLoS Biol 8:e1000316
Shapiro Y, Pandolf KB, Goldman RF (1982) Predicting sweat loss response to exercise, environment and clothing. Eur J Appl Physiol Occup Physiol 48:83–96
Shoji M, Katayama K, Sano K (2011) Absolute humidity as a deterministic factor affecting seasonal influenza epidemics in Japan. Tohoku J Exp Med 224:251–256
Steadman R (1979) The assessment of sultriness. Part I: a temperature-humidity index based on human physiology and clothing science. J Appl Meteorol 18:874–885
Strand LB, Barnett AG, Tong S (2011) The influence of season and ambient temperature on birth outcomes: a review of the epidemiological literature. Environ Res 111:451–462
Tamerius JD, Perzanowski MS, Acosta LM, Jacobsen JS, Goldstein IF, Quinn JW, Rundle AG, Shaman J (2013) Socioeconomic and outdoor meteorological determinants of indoor temperature and humidity in New York City dwellings. Weather Clim Soc 5:168–179
The Eurowinter Group (1997) Cold exposure and winter mortality from ischaemic heart disease, cerebrovascular disease, respiratory disease, and all causes in warm and cold regions of Europe. Lancet 349:1341–1346
Turner LR, Barnett AG, Connell D, Tong S (2012) Ambient temperature and cardiorespiratory morbidity: a systematic review and meta-analysis. Epidemiology 23:594–606
van Noort SP, Aguas R, Ballesteros S, Gomes MG (2011) The role of weather on the relation between influenza and influenza-like illness. J Theor Biol 298C:131–137
Ware WB, Ferron JM, Miller BM (2013) Introductory statistics: a conceptual approach using R. Routledge, New York
Weather Underground. http://www.wunderground.com/about/data.asp, Accessed October 3, 2014
Ye X, Wolff R, Yu W, Vaneckova P, Pan X, Tong S (2012) Ambient temperature and morbidity: a review of epidemiological evidence. Environ Health Perspect 120:19–28
Acknowledgments
We thank all study volunteers for their participation. This work was supported in part by National Institute of Environmental Health Sciences (NIEHS) grants ES000002, R21ES020194, and T32ES023770. JLN also received support from the Benjamin Greely Ferris, Jr. Fellowship Fund at the Harvard T.H. Chan School of Public Health.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Nguyen, J.L., Dockery, D.W. Daily indoor-to-outdoor temperature and humidity relationships: a sample across seasons and diverse climatic regions. Int J Biometeorol 60, 221–229 (2016). https://doi.org/10.1007/s00484-015-1019-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00484-015-1019-5