Trabalho a céu aberto: passado, presente e futuro sobre exposição ocupacional ao calor / Outdoor work: past, present, and future on occupational heat exposure

Resumo Considerando as mudanças climáticas e o impacto das temperaturas elevadas na saúde humana, especialmente devido ao aquecimento global, são relevantes as ações de prevenção ao calor voltadas aos trabalhadores que laboram a céu aberto. Neste ensaio, são apresentados resultados de recentes pesquisas, bem como destacadas inovações tecnológicas para monitoramento do calor no Brasil. Também são expostas reflexões sobre o futuro do trabalho a céu aberto diante das mudanças climáticas. O trabalho a céu aberto é em geral caracterizado por atividades pesadas, que geram elevado calor metabólico. Contudo, são escassos os esforços no campo da Saúde e Segurança do Trabalho para a busca de alternativas que minimizem ou eliminem os efeitos do calor para os trabalhadores. Além disso, as alternativas de proteção dos trabalhadores são reduzidas. O Monitor IBUTG é apresentado como inovação tecnológica de monitoramento remoto do calor em ambiente a céu aberto. Apesar das medidas de controle previstas em lei para proteção dos trabalhadores submetidos ao calor, em razão do aquecimento global, serão necessários intervenções inovadoras e controles especiais da exposição ao calor nos ambientes externos. Portanto, é desejável maior empenho na produção de conhecimento com vistas a fomentar a elaboração ou o aprimoramento de políticas públicas.

Abstract Given the current climate change and high-temperature impact on human health, especially due to global warming, actions for heat prevention focused on outdoor workers are relevant. This essay presents the results of recent research and highlights technological innovations for heat monitoring in Brazil. Also, it reflects on the future of outdoor work given climate change. Outdoor work is generally characterized as heavy, leading to higher metabolic heat production. However, Occupational Safety and Health have made few efforts to find alternatives to minimize or eliminate heat impact on workers. Moreover, the worker's protection alternatives are reduced. WBGT Monitor is presented as a technological innovation for remote heat monitoring in outdoor environments. Despite the control measures provided to workers subjected to heat, global warming demands innovative interventions and special exposure controls at outdoor workplaces. Thus, an increased commitment to knowledge production to elaborate or improve public policy is desirable.

Heat stress monitoring based on heart rate measurements.

Currently, occupational heat exposure is usually measured using environmental variables such as the wet bulb globe temperature index. The costs of heat stress monitoring include the acquisition of specialized equipment and the recruitment of trained personnel. In rapidly changing environments, such as outdoor settings, these assessments must be conducted on a daily basis. The wet bulb globe temperature index has been criticized as a measure of heat stress for its failure to account for individual differences in susceptibility to heat stress, age, body mass index, physical fitness, clothing, illnesses and use of alcohol or drugs. The objective of this study was to assess the relationship between heart rate and body temperature in heat-exposed workers to determine whether heart rate can be used to monitor and prevent heat stress and physiological strain. This study was based on previous literature as well as physiological and environmental data collected from 10 individuals engaged in heavy physical labor. Heart rate, which has been recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) as a possible measure of heat stress, follows a similar trend to body temperature with a slight temporal delay. Heart rate monitors with alarm systems could be developed to notify workers when to slow down their activities or take a break for thermal recovery, thereby contributing to the prevention of heat-related illness.

[Risk of exposure to heatstroke in sugarcane workers in São Paulo State, Brazil]. / Risco de exposição à sobrecarga térmica para trabalhadores da cultura de cana-de-açúcar no Estado de São Paulo, Brasil.

Environmental heat is an aggravating factor for sugarcane workers, and manual cane cutting is one of the heavy work activities that favor the generation of metabolic heat. This can combine with other precarious working conditions to produce heatstroke, potentially leading to serious complications and even death. The study aimed to quantify the risk of overheating in sugarcane cutters in São Paulo, Brazil. Drawing on a specific methodology, the study used four years of data to estimate the Globe Thermometer Wet Bulb Index based on light, moderate, and heavy activities. The results showed that the legal limit was exceeded for continuous activity in periods from 1 to 8 hours, which requires control measures in order to continue working. The principal observation was the risk of heatstroke in the three types of activity: light, moderate, and heavy. The limits were exceeded throughout the work shift on 7% of the days for heavy activity and on 3% of the days for moderate activity. In addition, the areas with the highest risk of heatstroke coincide with predominant cane-growing.

Risco de exposição à sobrecarga térmica para trabalhadores da cultura de cana-de-açúcar no Estado de São Paulo, Brasil / Risk of exposure to heatstroke in sugarcane workers in São Paulo State, Brazil / Riesgo de exposición a la sobrecarga térmica para trabajadores de plantaciones de caña de azúcar en el estado de São Paulo, Brasil

Resumo: O calor ambiental é um agravante às atividades dos trabalhadores da cultura de cana-de-açúcar, sendo o corte manual uma das atividades pesadas que favorece a elevada geração de calor metabólico. Isso associado com outras condições precárias de trabalho favorece o estresse térmico, podendo provocar graves doenças ou até levar à morte. O objetivo deste estudo é quantificar o risco de sobrecarga térmica que os cortadores de cana-de-açúcar de São Paulo, Brasil, são expostos. Por meio de metodologia específica, foram utilizados quatro anos de dados para estimar o Índice de Bulbo Úmido - Termômetro de Globo sob a consideração das atividades leve, moderada e pesada. Os resultados mostram extrapolação do limite legal de exposição para atividade contínua em períodos de 1 a 8 horas, o que requer medidas de controle para continuidade do trabalho. A principal constatação é a observância do risco de sobrecarga térmica para os três tipos de atividade: leve, moderada e pesada. Os limites de tolerância são ultrapassados durante todo o turno de trabalho em cerca de 7% dos dias, para atividade pesada, e em cerca de 3%, para atividade moderada. Além disso, percebeu-se que as áreas com maior risco de sobrecarga térmica são as mesmas onde há predominância da cultura de cana-de-açúcar.

Abstract: Environmental heat is an aggravating factor for sugarcane workers, and manual cane cutting is one of the heavy work activities that favor the generation of metabolic heat. This can combine with other precarious working conditions to produce heatstroke, potentially leading to serious complications and even death. The study aimed to quantify the risk of overheating in sugarcane cutters in São Paulo, Brazil. Drawing on a specific methodology, the study used four years of data to estimate the Globe Thermometer Wet Bulb Index based on light, moderate, and heavy activities. The results showed that the legal limit was exceeded for continuous activity in periods from 1 to 8 hours, which requires control measures in order to continue working. The principal observation was the risk of heatstroke in the three types of activity: light, moderate, and heavy. The limits were exceeded throughout the work shift on 7% of the days for heavy activity and on 3% of the days for moderate activity. In addition, the areas with the highest risk of heatstroke coincide with predominant cane-growing.

Resumen: El calor ambiental es un agravante para las actividades de los trabajadores de plantaciones de caña de azúcar, siendo el corte manual una de las actividades pesadas que favorece la elevada generación de calor metabólico. Esto, asociado con otras condiciones precarias de trabajo, favorece el estrés térmico, pudiendo provocar graves enfermedades o incluso llevar a la muerte. El objetivo de este estudio es cuantificar el riesgo de sobrecarga térmica a la que los cortadores de caña de azúcar de São Paulo, Brasil, están expuestos. Mediante una metodología específica, se utilizaron cuatro años de datos para estimar el Índice de Bulbo Húmedo-Termómetro de Globo, considerando a las actividades como: leves, moderadas y pesadas. Los resultados muestran la extrapolación del límite legal de exposición para la actividad continua en períodos de 1 a 8 horas, lo que requiere medidas de control para la continuidad del trabajo. La principal constatación es la observancia del riesgo de sobrecarga térmica para los tres tipos de actividad: leve, moderada y pesada. Los límites de tolerancia se sobrepasan durante todo el turno de trabajo en cerca de un 7% dos días, en el caso de la actividad pesada, y en cerca de un 3% en la actividad moderada. Además, se percibió que las áreas con mayor riesgo de sobrecarga térmica son las mismas donde hay predominancia de plantaciones de caña de azúcar.

Wet-bulb globe temperature index estimation using meteorological data from São Paulo State, Brazil.

It is well known that excessive heat exposure causes heat disorders and can lead to death in some situations. Evaluation of heat stress on workers performing indoor and outdoor activities is, nowadays, conducted worldwide by wet-bulb globe temperature (WBGT) index, which calculation parameters are dry-bulb, natural wet-bulb, and globe temperatures, which must be measured at the same time and in location where the worker is conducting his/her activities. However, for some activities performed in large outdoor areas such as those of agricultural ones, it is not feasible to measure directly those temperatures in all work periods and locations where there are workers. Taking this into account, this work aims to introduce a WBGT index estimation using atmospheric variables observed by automatic meteorological stations. In order to support our estimation method, we used, as a test-bed, data recorded in the State of São Paulo (SP), Brazil. By adding the cloudiness factor in the calculation through measurement of solar radiation, the algorithm proved to be as efficient as those mentioned in this work. It was found that this method is viable, with WBGT-estimated values obtained from meteorological data measured by stations with a distance of less than 80 km. This estimate can be used for monitoring heat stress in real time as well as to investigate heat-related disorders and agricultural work.

[Analysis of the contribution of meteorological variables to thermal stress associated with death among sugarcane cutters]. / Análise da contribuição das variáveis meteorológicas no estresse térmico associada à morte de cortadores de cana-de-açúcar.

Sugarcane cutters perform heavy work under adverse conditions. Environmental factors can be an aggravating factor for thermal stress among these workers. This study analyzed the atmospheric conditions on the day of death of 14 sugarcane cutters in São Paulo State, Brazil. Historical data for temperature, humidity, wind, and sunlight were compared with the same meteorological variables on the days the deaths that occurred. The meteorological data were obtained from a reanalysis of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). In 10 of the 14 cases, the temperature on the day of death was higher than or equal to the mean plus the standard deviation. In six of these cases, the temperature reached or came close to record levels. These findings suggest that atmospheric conditions can be an important factor in the analysis of overall work conditions for sugarcane cutters.

Análise da contribuição das variáveis meteorológicas no estresse térmico associada à morte de cortadores de cana-de-açúcar / Analysis of the contribution of meteorological variables to thermal stress associated with death among sugarcane cutters

Os cortadores de cana-de-açúcar exercem atividade muito pesada e em condições precárias de trabalho. Além disso, fatores ambientais podem ser um importante agravante à sobrecarga térmica desses trabalhadores. Neste artigo, analisa-se a condição atmosférica no dia da morte de 14 trabalhadores do corte de cana-de-açúcar no Estado de São Paulo, Brasil. Compara-se valores estatísticos históricos da temperatura, umidade, vento e radiação com os valores destas variáveis meteorológicas observadas no dia de cada óbito. Os dados atmosféricos foram obtidos da reanálise do National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). Em 10 dos 14 casos analisados, as temperaturas observadas nos dias dos óbitos foram maiores ou iguais à média somada ao desvio-padrão. Em seis desses casos o valor da temperatura atingiu ou ficou muito próxima do recorde histórico. Constatou-se que a condição atmosférica pode ser um fator importante a ser considerado na análise das condições gerais de trabalho dos cortadores de cana-de-açúcar.

Sugarcane cutters perform heavy work under adverse conditions. Environmental factors can be an aggravating factor for thermal stress among these workers. This study analyzed the atmospheric conditions on the day of death of 14 sugarcane cutters in São Paulo State, Brazil. Historical data for temperature, humidity, wind, and sunlight were compared with the same meteorological variables on the days the deaths that occurred. The meteorological data were obtained from a reanalysis of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). In 10 of the 14 cases, the temperature on the day of death was higher than or equal to the mean plus the standard deviation. In six of these cases, the temperature reached or came close to record levels. These findings suggest that atmospheric conditions can be an important factor in the analysis of overall work conditions for sugarcane cutters.

Associação de variáveis meteorológicas com os afastamentos do trabalho devido a doenças respiratórias: um estudo entre trabalhadores dos Correios de Santa Catarina / Meteorological variables association with sick leave due to respiratory diseases a study involving post-office workers in the state of Santa Catarina, Brazil

Introdução: As doenças do aparelho respiratório (DAR) em trabalhadores são, com frequência, atribuídas ao ambiente de trabalho ou ao tipo de atividade. Poucos estudos relacionam as DAR com as condições de tempo. Objetivo: Este artigo tem como objetivo identificar a existência desta relação através da comparação da taxa de afastamento do trabalho com as médias mensais de variáveis meteorológicas. Métodos: Para tanto, calculou-se a correlação dos afastamentos com as médias mensais de temperatura e umidade, com os valores mínimos mensais de temperatura e umidade e com a maior queda de temperatura em 24h ocorrida no mês. A série de dados meteorológicos com melhor correlação foi dividida em quartis (25%) para identificar os valores típicos de afastamento em situações extremas de temperatura ou umidade. Os afastamentos por DAR foram calculados em trabalhadores dos Correios de Santa Catarina e os dados meteorológicos foram obtidos da reanálise de modelos numéricos. O período analisado compreendeu janeiro de 2001 a dezembro de 2007, totalizando 84 meses. Resultados: Os afastamentos do trabalho devido às DAR obtiveram melhor associação, em ordem de importância, com a temperatura média do mês, a temperatura mínima do mês e o maior declínio de temperatura do mês. Todas essas correlações obtiveram significância estatística de 0,1%. A umidade do ar não demonstrou associação com a taxa de afastamento. Conclusão: Conclui-se que as maiores taxas de afastamento do trabalho devido às DAR ocorrem nos meses mais frios e secos.

Introduction: Workers respiratory diseases are frequently accounted for either their labor environment or sort of activity. Few studies relate them to weather conditions. Objectives: This article aims at identifying this relation by comparing sick leave rates with meteorological variables monthly averages. Methods: Calculating statistically the correlation between sick leave and the following factors: monthly average temperatures and humidity; monthly minimum temperatures and humidity; the highest temperature drop in 24 hours in a month. A series of the best correlated meteorological data was divided into quartiles (25 %) to identify typical sick leave values in extreme temperature and humidity situations. Rates of sick leave due to respiratory diseases were determined in post-office workers in the state of Santa Catarina, Brazil, and meteorological data were obtained from reanalysis of numeric models. The investigated period lasted from January 2001 to December 2007, amounting to 84 months. Results: As far as importance is concerned, sick leave due to respiratory diseases was mostly related to the monthly average temperature, the lowest monthly temperature and the highest monthly temperature drop. All these correlations obtained 0.1% statistical significance. Humidity has not been related to sick leave rates. Conclusion: The highest sick leave rates due to respiratory diseases occur mostly in the coldest and driest months of the year.