Respiratory health effects of occupational exposure to charcoal dust in Namibia.
Charcoal processing activities can increase the risk of adverse respiratory outcomes.



To determine dose-response relationships between occupational exposure to charcoal dust, respiratory symptoms and lung function among charcoal-processing workers in Namibia.



A cross-sectional study was conducted with 307 workers from charcoal factories in Namibia. All respondents completed interviewer-administered questionnaires. Spirometry was performed, ambient and respirable dust levels were assessed in different work sections. Multiple logistic regression analysis estimated the overall effect of charcoal dust exposure on respiratory outcomes, while linear regression estimated the exposure-related effect on lung function. Workers were stratified according to cumulative dust exposure category.



Exposure to respirable charcoal dust levels was above occupational exposure limits in most sectors, with packing and weighing having the highest dust exposure levels (median 27.7 mg/m3, range: 0.2-33.0 for the 8-h time-weighted average). The high cumulative dust exposure category was significantly associated with usual cough (OR: 2.1; 95% CI: 1.1-4.0), usual phlegm (OR: 2.1; 95% CI: 1.1-4.1), episodes of phlegm and cough (OR: 2.8; 95% CI: 1.1-6.1), and shortness of breath. A non-statistically significant lower adjusted mean-predicted % FEV1 was observed (98.1% for male and 95.5% for female) among workers with greater exposure.



Charcoal dust levels exceeded the US OSHA recommended limit of 3.5 mg/m3for carbon-black-containing material and study participants presented with exposure-related adverse respiratory outcomes in a dose-response manner. Our findings suggest that the Namibian Ministry of Labour introduce stronger enforcement strategies of existing national health and safety regulations within the industry.
a Department of Health Sciences , Namibia University of Science and Technology , Windhoek , Namibia.
Ndinomholo
0000-0002-6397-8597
N
Hamatui
b Discipline of Occupational and Environmental Health , University of KwaZulu-Natal , Durban , South Africa.
Rajen N
0000-0002-2318-4004
RN
Naidoo
c Department of Civil and Environmental Engineering , Namibia University of Science and Technology , Windhoek , Namibia.
Nnenesi
N
Kgabi
D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000032:analysis; D002606:Charcoal / Q000009:adverse effects* / Q000032:analysis; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects* / Q000032:analysis; D008297:Male; D009276:Namibia / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D016017:Odds Ratio; D012120:Respiration Disorders / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D013147:Spirometry; D014797:Vital Capacity / Q000187:drug effects; D055815:Young Adult
D000395:Air Pollutants, Occupational; D004391:Dust; D002606:Charcoal
Exposure; Lung impairment and respiratory symptoms; Namibia; Respirable charcoal dust
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