Airway effects of traffic-related air pollution on outdoor workers

Short-term association of in-vehicle ultrafine particles and black carbon concentrations with respiratory health in Parisian taxi drivers

INTRODUCTION

Professional drivers are exposed inside their vehicles to high levels of air pollutants due to the considerable time they spend close to motor vehicle emissions. Little is known about ultrafine particles (UFP) or black carbon (BC) adverse respiratory health effects compared to the regulated pollutants.

OBJECTIVES

We aimed to study the short-term associations between UFP and BC concentrations inside vehicles and (1) the onset of mucosal irritation and (2) the acute changes in lung function of Parisian taxi drivers during a working day.

METHODS

An epidemiological study was carried out on 50 taxi drivers in Paris. UFP and BC were measured inside their vehicles with DiSCmini® and microAeth®, respectively. On the same day, the frequency and the severity of nose, eye, and throat irritations were self-reported by each participant and a spirometry test was performed before and after the work shift. Multivariate analysis was used to evaluate the associations between in-taxis UFP and BC concentrations and mucosal irritation and lung function, after adjustment for potential confounders.

RESULTS

In-taxis UFP concentrations ranged from 17.9 to 37.9 × 10³ particles/cm³ and BC concentrations from 2.2 to 3.9 μg/m3, during a mean of 9 ± 2 working hours. Significant dose-response relationships were observed between in-taxis UFP concentrations and both nasal irritation and lung function. The increase of in-taxis UFP (for an interquartile range of 20 × 10³ particles/cm³) was associated to an increase in nasal irritation (adjusted OR = 6.27 [95% CI: 1.02 to 38.62]) and to a reduction in forced expiratory flow at 25-75% by -7.44% [95% CI: -12.63 to -2.24], forced expiratory volume in one second by -4.46% [95% CI: -6.99 to -1.93] and forced vital capacity by -3.31% [95% CI: -5.82 to -0.80]. Such associations were not found with BC. Incident throat and eye irritations were not related to in-vehicle particles exposure; however, they were associated with outdoor air quality (estimated by the Atmo index) and in-vehicle humidity, respectively.

CONCLUSION

To our knowledge, our study is the first to show a significant association, within a short-period of time, between in and vehicle UFP exposure and acute respiratory effects in professional drivers.

Does occupational air pollution threaten the lung health of indoor workers more than those of bus drivers?: a cross-sectional study

AIM

This study aimed to evaluate the lung health between professional bus drivers and white collar workers in metropolis municipality from Turkey.

MATERIAL AND METHODS

Out of 126 bus drivers and 1100 office employees, data were analyzed from 243 indoor employees and 57 bus drivers. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, forced expiratory flow (FEF) 25-75% were measured, some data were collected with a questionnaire (work and environmental anamnesis, symptoms, smoking).

RESULTS

The mean (±SD) values for FVC, FVC percent predicted value, FEV1, FEV1 percent predicted value, FEV1/FVC were 4.33 ± 0.99L, 96.5 ± 18.2%, 3.31 ± 0.87L, 84.5 ± 18.2%, 76.30 ± 9.23%, respectively. Sixty-six participants (22%) had FEV1/FVC proportions of less than 70%. After weighing for the propensity scores, there was a significant difference between bus drivers and indoor workers concerning FEV1/FVC grouping; while 65 (26.1%) indoor workers had FEV1/FVC proportions less than 70%, there were only two (3.9%) bus drivers (Chi-Square = 12.009, p = .001). The mean spirometry values were significantly different between the two groups in favor of the bus drivers (p < .05). Night cough was much more seen in the indoor workers (Chi-Square test = 9.019, p = .003).

CONCLUSION

We conclude that there are no health risks associated with bus driving in a metropolitan city, concerning lung functions.

Effect of Implementing Electronic Toll Collection in Reducing Highway Particulate Matter Pollution

Highway vehicle emissions can result in adverse health problems to nearby residents and workers, especially during traffic congestion. In response, the policy to implement electronic toll collection (ETC) has helped alleviate traffic congestion, as compared to manual toll collection (MTC) and has led to reduced air pollution and improved public health. However, the effect of ETC in reducing particulate matter polluting the air is not well understood, especially in the ultrafine particle (UFP) range (particle diameter <100 nm). To the best of our knowledge, this is the first study to investigate how ETC affects the traffic pattern and air quality, especially UFP and PM_2.5. We selected a site in Tainan, Taiwan, and measured UFP and PM_2.5 concentrations before and after the construction of the ETC system. The computed traffic volumes during peak travel periods (7:00 AM to 9:00 AM and 4:00 PM to 6:00 PM) respectively, accounted for approximately 23-25% and 14-18% before and after the implementation of ETC, indicating that peak traffic volumes were more homogeneous after ETC. Moreover, the results indicate that the full implementation of ETC can help reduce UFP number concentrations and PM_2.5 mass concentrations in the highway downwind area by 4 × 10³ #/cm³ and 20.5 μg/m³, respectively. After the full implementation of the ETC, significant reductions in both the UFP number concentration and PM_2.5 mass concentration were seen. Furthermore, excessive lifetime cancer risks (ELCR) from exposure to PM_2.5 and UFP together were reduced 49.3% after the implementation of the ETC. Accordingly, ETC not only helps alleviate traffic congestion but also reduces traffic emissions and lifetime cancer risk for people living or working near highways.

Health Risks Associated with Occupational Exposure to Ambient Air Pollution in Commercial Drivers: A Systematic Review

Ambient air pollution is a major global health problem and commercial drivers are particularly exposed to it. As no systematic assessment of the health risks associated with occupational exposure to ambient air pollution in this population had yet been carried out, we conducted a systematic review using a protocol-driven strategy. Papers published from inception to April 20, 2018 in MEDLINE, EMBASE, CINAHL, African journals online, the Cochrane library, ISRCTN WHO ICTRP, and the Web of Science and Scopus databases were screened for inclusion by two independent reviewers. Original articles with at least an available abstract in English or French were included. The initial search retrieved 1454 published articles of which 20 articles were included. Three studies reported a significant difference in white blood cells (10⁶/L) among commercial motorcyclists compared to rural inhabitants (5.041 ± 1.209 vs. 5.900 ± 1.213, p = 0.001), an increased risk of lung cancer (RR = 1.6, 95%CI 1.5–1.8) in bus drivers and an increased standardized mortality ratio (SMR) in bus drivers from Hodgkin’s lymphoma (SMR 2.17, 95%CI 1.19–3.87) compared to white-collar workers. Other studies also found that drivers had more oxidative DNA damage and chromosome breaks. Four papers failed to demonstrate that the drivers were more exposed to air pollution than the controls. Three other studies also reported no significant difference in lung function parameters and respiratory symptoms. The genetic polymorphisms of detoxifying enzymes were also not homogeneously distributed compared to the controls. There is some evidence that occupational exposure to ambient air pollution among commercial drivers is associated with adverse health outcomes, but the existing literature is limited, with few studies on small sample size, methodological weaknesses, and contradictory findings—thus, further research is recommended.

Are metals and pyrene levels additional factors playing a pivotal role in air pollution-induced inflammation in taxi drivers?

This study aimed to evaluate which xenobiotic (As, Hg, Pb or pyrenes) is primarily responsible for the inflammatory process in taxi drivers. Multiple regression analysis showed that Hg is the main xenobiotic responsible for the increase of cytokine levels. These associations suggest that co-exposure to pollutants could be a risk factor for health effects.

A cross-sectional study with an improved methodology to assess occupational air pollution exposure and respiratory health in motorcycle taxi driving

INTRODUCTION

Motorcycle taxi driving is common in many African cities. This study tested whether this occupation is associated with more respiratory disorders in a context of widespread urban air pollution with an improved methodology.

METHODS

In a cross sectional study we compared 85 male motorcycle taxi drivers in the capital city of the Republic of Benin (Cotonou) with an age and neighborhood matched control group. All participants carried a portable carbon monoxide data logger for 8 hours per day to assess exposure to air pollution. Respiratory symptoms were obtained using a standardized questionnaire and pulmonary function was assessed by spirometry.

RESULTS

The two groups did not differ significantly (p>0.10) in their age, height, educational level, and exposures to smoke from biomass fuels and tobacco products. The taxi drivers were exposed to higher mean (SD) levels of carbon monoxide (7.6±4.9ppmvs. 5.4±3.8ppm p=0.001). They reported more phlegm and tended to have slightly lower levels of lung function, although these differences were not statistically significant.

CONCLUSION

In this cross sectional study of young motorcycle taxi drivers with substantial exposure to urban traffic and a matched control group, we found no evidence for respiratory impairment. A follow-up of such study population with other pollution exposure surrogate and other clinical endpoint may provide a more robust conclusion regarding the exposure response in this professional group.