2011), South Korea ( Kysely and Kim 2009), and several Central and South American cities ( Bell et al. The heat index has been used as a measure of heat exposure in studies throughout the world, including in studies of the United States (e.g., Zanobetti and Schwartz 2006), cities throughout Europe (e.g., Michelozzi et al. 2012), and development of synoptic-scale heat warning systems ( Sheridan and Kalkstein 2004 Smoyer-Tomic and Rainham 2001). Additionally, the heat index is widely used in environmental health research, including studies of air pollution exposures (e.g., Zanobetti and Schwartz 2005), outdoor temperature exposures (e.g., Barnett et al. National Weather Service (NWS) has linked different heat index values to environmental health threats, and the NWS uses heat index for its excessive heat warnings ( NOAA 2009). However, it has become a popular exposure metric in environmental health, particularly in its approximated “heat index” form. Īpparent temperature was developed to measure thermal comfort rather than to study human health ( Steadman 1994). This index, particularly the simplified version that relies only on air temperature and moisture ( Steadman 1979a), is often also called the “heat index”. By expressing weather conditions in terms of the equivalent temperature if dew point temperature were 14☌, Steadman translated combinations of air moisture and temperature into a single scale, measured in the same units as air temperature. Steadman’s apparent temperature translates current weather conditions (air temperature and air moisture in the most basic formulations) into the air temperature that would “feel” the same to humans if dew point temperature were 14.0☌/57.2☏ ( Rothfusz 1990 Steadman 1979a). To estimate heat exposure, many environmental health studies use indices meant to capture the combined experience of several weather factors, such as the Universal Thermal Climate Index ( UTCI 2012) and the humidex, which is used by Canada’s weather office ( Environment Canada 2013).One of the most popular indices for environmental health research is Steadman’s apparent temperature ( Steadman 1979a, 1979b, 1984), a version of which provides the basis for heat advisories in many U.S. Beyond heat–health research, numerous other environmental health studies assess exposure to outdoor heat as a potential confounder (e.g., research on air pollution and health). Under climate change, heat waves are expected to be more frequent and severe ( Meehl and Tebaldi 2004).
2003), as well as increased risk of hospitalizations and adverse birth outcomes (e.g., Anderson et al. Heat waves can produce catastrophic death tolls, including > 14,000 excess deaths during the 2003 French heat wave ( Hémon et al. Research that addresses health effects of weather-related heat exposure is critical both to limit present-day dangers from heat and also to prepare for future weather. Methods to calculate the heat index as an exposure metric in environmental health research. Careful choice of a heat index algorithm can help ensure reproducible and consistent environmental health research.Ĭitation: Anderson GB, Bell ML, Peng RD. Our analysis demonstrated that methods to calculate heat index are inconsistent across studies. National Weather Service’s algorithm.Ĭonclusion: We identified 21 separate heat index algorithms used in environmental research.
ET WEATHER CALCULATOR SOFTWARE
To aid environmental health researchers, we have created open-source software in R to calculate the heat index using the U.S.
However, a few algorithms are potentially problematic, especially in certain weather conditions (e.g., very low relative humidity, cold weather).
Additionally, most different algorithms generate closely correlated heat index values. Results: Although environmental studies differ in how they calculate heat index values, most studies’ heat index algorithms generate values consistent with apparent temperature.
Objective and Methods: We investigated 21 separate heat index algorithms found in the literature to determine a) whether different algorithms generate heat index values that are consistent with the theoretical concepts of apparent temperature and b) whether different algorithms generate similar heat index values. However, the method of calculating heat index varies across environmental studies, which could mean that studies using different algorithms to calculate heat index may not be comparable. To measure heat exposure, environmental health studies often use heat index, which incorporates both air temperature and moisture. Background: Environmental health research employs a variety of metrics to measure heat exposure, both to directly study the health effects of outdoor temperature and to control for temperature in studies of other environmental exposures, including air pollution.
0 kommentar(er)
