Occupational Tasks Influencing Lung Function and Respiratory Symptoms Among Charcoal-Production Workers: A Time-Series Study

BACKGROUND: Tasks involved in traditional charcoal production expose workers to various levels of charcoal dust and wood smoke. This study aimed to identify specific tasks influencing lung function and respiratory symptoms. METHODS: Interviews, direct observation, and task/symptom checklists were used to collect data from 50 charcoal-production workers on 3 nonwork days followed by 11 workdays. The peak expiratory flow rate (PEFR) was measured four times per day. RESULTS: The PEFR was reduced and the prevalence of respiratory symptoms increased over the first 6–7 workdays. The PEFR increased until evening on nonwork days but not on workdays. Loading the kiln and collecting charcoal from within the kiln markedly reduced the PEFR and increased the odds of respiratory symptoms. CONCLUSION: Tasks involving entry into the kiln were strongly associated with a short-term drop in the PEFR and the occurrence of respiratory symptoms, suggesting a need for the use of protective equipment and/or the operation of an effective kiln ventilation system.

Low-Oxygen Atmosphere and its Predictors among Agricultural Shallow Wells in Northern Thailand

BACKGROUND: In 2006, three farmers died at the bottom of an agricultural shallow well where the atmosphere contained only 6% oxygen. This study aimed to document the variability of levels of oxygen and selected hazardous gases in the atmosphere of wells, and to identify ambient conditions associated with the low-oxygen situation. METHODS: A cross-sectional survey, conducted in June 2007 and July 2007, measured the levels of oxygen, carbon monoxide, hydrogen sulfide, and explosive gas (percentage of lower explosive limit) at different depths of the atmosphere inside 253 wells in Kamphaengphet and Phitsanulok provinces. Ambient conditions and well use by farmers were recorded. Carbon dioxide was measured in a subset of wells. Variables independently associated with low-oxygen condition (2 days vs. 25,000 ppm) in seven wells with a low oxygen level. CONCLUSION: Oxygen concentrations in the wells vary widely even within a small area and decrease with increasing depth.