Calculating Workplace WBGT from Meteorological Data: A Tool for Climate Change Assessment

Abstract

The WBGT heat stress index has been well tested under a variety of climatic conditions and quantitative links have been established between WBGT and the work-rest cycles needed to prevent heat stress effects at the workplace. While there are more specific methods based on individual physiological measurements to determine heat strain in an individual worker, the WBGT index is used in international and national standards to specify workplace heat stress risks. In order to assess time trends of occupational heat exposure at population level, weather station records or climate modelling are the most widely available data sources. The prescribed method to measure WBGT requires special equipment which is not used at weather stations. We compared published methods to calculate outdoor and indoor WBGT from standard climate data, such as air temperature, dew point temperature, wind speed and solar radiation. Specific criteria for recommending a method were developed and original measurements were used to evaluate the different methods. We recommend the method of Liljegren et al.

Mapping Occupational Heat Exposure and Effects in South-East Asia: Ongoing Time Trends 1980^|^ndash;2011 and Future Estimates to 2050

“…We had the opportunity to link NOAA data on temperature and humidity with a NASA website data on solar radiation (http://power.larc.nasa.gov). Mathematical formulas for calculating WBGT with and without SR data is available [26][27][28] , and we used these formulas with hourly data to calculate the indoor and outdoor WBGT levels for the four hottest afternoon hours (12.00−15.59 h) when the SR is at its highest level (labeled WBGTmax). Calculations were made for the four indicator stations with the most complete hourly data sets available for 1999, as an example of a year within the time range of this study .…”

“…The basic input data from GSOD on daily mean and maximum temperature (and hourly mean temperatures for indicator weather stations) as well as dew point (a descriptor of absolute humidity) were used to calculate the heat stress indicator WBGT (Wet Bulb Globe Temperature; see ref 1 ) using published mathematical formulas 26,27) . In order to standardise the calculations for indoor workplaces (or in full shade outdoors) it was assumed that wind speed (air movement over the skin) was 1 m/s and there was no heat radiation exposure.…”

Risco de exposição à sobrecarga térmica para trabalhadores da cultura de cana-de-açúcar no Estado de São Paulo, Brasil

“…Existem muitos métodos de estimativa do IBUTG propostos na literatura e testados em várias partes do mundo 39,40,41,42,43,44,45,46,47 . Neste estudo, utiliza-se o método proposto recentemente por Maia et al 48 , o qual utilizou dados meteorológicos observados no Estado de São Paulo para o seu desenvolvimento.…”

Empirical Approach to Outdoor WBGT from Meteorological Data and Performance of Two Different Instrument Designs

“…Lemke and Kjellstrom recently reviewed a range of rational and empirical approaches to predict WBGT from meteorological data 3) . There is utility in being able to predict outdoor WBGT from meteorological data for climate modeling 3) and real-time monitoring for heat stress management 4) .…”

“…Lemke and Kjellstrom recently reviewed a range of rational and empirical approaches to predict WBGT from meteorological data 3) . There is utility in being able to predict outdoor WBGT from meteorological data for climate modeling 3) and real-time monitoring for heat stress management 4) . For general areas (e.g., agriculture and road maintenance) as well as fixed locations that vary with ambient conditions, surrogate measures based on actual or projected meteorological data may be helpful to predict the local WBGT.…”