Citation

Grundstein AJ, Dowd J, Meentemeyer V. Bull. Am. Meterol. Soc. 2010; 91(9): 1183-1191.

Copyright

(Copyright © 2010, American Meteorological Society, Publisher Allen Press)

DOI

10.1175/2010BAMS2912.1

PMID

unavailable

Abstract

The danger of leaving young children unattended in vehicles has been well documented. There are no unique codes for identifying vehicle-related hyperthermia deaths in the International Classifica- tion of Diseases (ICD) or in any U.S. federal or state data source (Guard and Gallagher 2005). However, vehicle-related hyperthermia deaths in children in the United States have been constructed from news accounts. Guard and Gallagher (2005) observed an average of 29 deaths per year during the years 1995-2002, while a more extensive dataset by Null (2009) observed an average of 37 deaths per year during the years 1998-2009. Most cases (54%) involve caregivers simply forgetting their children; however, more than a quarter of vehicle-related hyperthermia deaths (27%) involve children that were intentionally left in the car (Guard and Gallagher 2005). In some cases, parents did not want to disturb a sleeping child but were unaware of how quickly the car could heat up. Such behavior indicates a clear lack of understanding by parents and caregivers about the dangers of leaving children unattended in vehicles. The interior of a car, along with the particular case of a child strapped into a child safety seat, represents a unique environment that may create particularly dangerous conditions. Multiple studies have investigated how ventilation, shading, and different meteorological conditions may affect maximum cabin temperatures and rates of temperature change. With the car in direct sunlight and no ventilation, maximum temperatures may reach values exceeding 70°C. These stunningly high temperatures are caused by a greenhouse effect, where the windows are transparent to solar radiation but opaque to longwave radiation. As a result, a positive net radiation balance occurs that leads to heating. In addition, the lack of ventilation from closed windows reduces the transport of energy via convection and further contributes to heating. Zumwalt and Petty (1976) note that exposure to high environmental temperatures only leads to a large rise in body temperature when the temperature-regulating mechanisms are not oper- ating efficiently. In a hot vehicle without ventilation, physiological mechanisms typically used for cooling, including longwave radiation and convection, would be ineffective. Furthermore, the efficiency of evaporative cooling would be reduced as evaporated perspiration accumulated in the vehicle. This research will focus on providing information that may aid public officials, child safety advocates, and the media in better educating the public about the dangers of leaving children unattended in vehicles.

RESULTS from this study may also be used as part of a public health response to a heat health warning to emphasize the extreme danger of vehicle-related hyperthermia in children during those unusually hot periods. The first portion of the study determines maximum temperature change at different time intervals using carefully positioned high-temporal-resolution temperature sensors. An extension from previous work involves placing the results in an easy-to-use table of vehicle temperature changes that shows conditions that may occur under the most severe circumstances. In addition, previous studies have discussed but have not quantified how the environmental conditions in a car would affect the energy budget of a child (e.g., Zumwalt and Petty 1976; King et al. 1981). Thus, a human heat balance model will be used to investigate the energy budget of a child in a hot car and the influence of variations in humidity and sun exposure on levels of heat stress.

KW: Hyperthermia in automobiles

Language: en