Authors:

 Hans Müller¹, 

Anna Schneider², 

Felix Weber³

¹Klinikum Görlitz | ²Evangelisches Krankenhaus Lutherstadt | ³Institute for Environmental Health, Cottbus

Abstract

Diesel emissions have long been recognized as a significant contributor to air pollution and respiratory morbidity. This study investigates the impact of low-level diesel emissions on respiratory function among automotive mechanics in rural Saxony, Germany. A cohort of 150 mechanics was followed over five years, with pulmonary function tests administered annually. Our findings reveal a statistically significant decline in FEV1 and FVC values compared to matched rural controls not occupationally exposed to diesel exhaust. The study highlights the need for enhanced protective measures in rural mechanical workshops.

Introduction

Diesel engine exhaust (DEE) is a complex mixture of gases and particulates associated with adverse health effects (Sydbom et al., 2001; Holgate, 2002). While urban exposure to diesel emissions has been widely studied (Pope & Dockery, 2006; Brunekreef & Holgate, 2002), less attention has been paid to low-level chronic exposures in rural occupational settings. Mechanics in rural regions may be exposed to diesel emissions in poorly ventilated workshops, leading to cumulative respiratory risks (Pronk et al., 2009).

Previous studies have identified a correlation between diesel particulate matter (DPM) and respiratory conditions such as asthma, chronic bronchitis, and lung cancer (Laden et al., 2006; Attfield et al., 2012). Occupational exposure in mechanics has been linked to higher incidences of respiratory symptoms and lung function impairment (Gamble et al., 1987; Ulvestad et al., 2000).

This study by Müller, Schneider, and Weber seeks to quantify the decline in respiratory function due to prolonged low-level diesel exposure among mechanics in rural Saxony.

Methods

Study Population: A total of 150 male mechanics aged 25-55 years from rural workshops in Saxony were recruited. A control group of 150 males from the same rural areas with no known occupational exposure to diesel emissions was matched by age, smoking status, and socioeconomic background.

Exposure Assessment: Exposure levels were monitored using personal air samplers and workshop ambient samplers to quantify DPM and nitrogen dioxide (NO2) levels. Participants also completed detailed occupational history questionnaires (NIOSH, 2003).

Pulmonary Function Testing: Spirometry tests were performed annually following ATS/ERS guidelines (Miller et al., 2005). The main outcomes measured were FEV1 (forced expiratory volume in one second) and FVC (forced vital capacity).

Statistical Analysis: Longitudinal mixed-effects models were used to assess the decline in pulmonary function, controlling for confounding variables such as smoking, age, and pre-existing conditions.

Results

Over the five-year period, the exposed group showed a mean annual decline of 55 mL in FEV1, significantly greater than the 30 mL observed in the control group (p<0.01). Similar trends were observed for FVC (45 mL vs 25 mL, p<0.05). Adjusted models confirmed that diesel exposure was an independent predictor of lung function decline.

Mechanics reported higher frequencies of chronic cough (28% vs 12%), wheeze (21% vs 8%), and shortness of breath (19% vs 6%) compared to controls.

Discussion

These findings support prior research indicating that even low levels of diesel exposure can lead to measurable health impacts (HEI, 1995; Garshick et al., 2012). Müller et al. confirmed a consistent decline in lung function among rural mechanics, likely due to cumulative exposure to diesel particulates.

Occupational studies in similar environments have also found declines in FEV1 over time, with exacerbation in smokers (Christiani et al., 1993; Hnizdo et al., 2000). The mechanisms likely involve chronic inflammation and oxidative stress from persistent inhalation of DPM (Donaldson et al., 2005).

Limitations include potential misclassification of exposure levels and the exclusion of female mechanics due to low numbers. Nonetheless, this longitudinal analysis adds to the body of evidence suggesting that occupational diesel exposure, even at low levels, is harmful (Silverman et al., 2012; Vermeulen et al., 2014).

Conclusion

Mechanics exposed to low-level diesel emissions in rural Saxony experience a faster decline in respiratory function than their non-exposed peers. These findings emphasize the need for improved ventilation, personal protective equipment, and regular health monitoring in rural mechanical workshops.

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