Exposure of Taxi Drivers to Ultrafine Particles and Black Carbon Within Their Vehicles

Study Overview
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Brief Summary
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Brief Summary Short description of the protocol intended for the lay public. Include a brief statement of the study hypothesis. (Limit: 5000 characters) Example: The purpose of this study is to determine whether prednisone, methotrexate, and cyclophosphamide are effective in the treatment of rapidly progressive hearing loss in both ears due to autoimmune inner ear disease (AIED). This project is part of a research field on the role, not yet fully understood, of atmospheric pollution, especially from road traffic, on respiratory health and allergies, particularly on the development / onset of symptoms and functional disturbances. The ultrafine fraction of particles (UFPs - particles smaller than 100 nm in diameter) is of recent interest because of their ability to induce inflammatory effects, oxidative stress and may contribute to the exacerbation of asthma symptoms in susceptible individuals. UFPs, with their high number concentration and surface area and their small diameter are able not only to convey other contaminants, but also to contribute to a high deposition efficiency, into the alveoli in the lungs. Recently it appeared relevant to be interested in black carbon (BC), components of PM2.5 (particulate matter with a diameter less than 2.5 micrometers), suspected of being responsible for their toxicity. Current epidemiological knowledge of the effects of UFPs and BC are few as compared to those on fine particles. Some professionals, such as police, drivers (taxis, truckers ...), delivery men, postal workers, workers on roads and highways, etc. are heavily exposed, during their working hours, to air pollution due to road traffic. These occupational groups appear to be at greater risk for developing respiratory, cardiovascular and neurological diseases than the general population. Occupational exposure to diesel exhaust has been associated with an increased risk of lung cancer mortality and chronic obstructive pulmonary disease. Occupational exposure to UFPs and BC has rarely been measured due to a lack of suitable devices. Therefore, this project's originality consists in measuring UFPs and BC by using portable devices developed in the recent years. The use of these devices, linking their recordings with ventilatory measures and repeating them, offers the rare opportunity to study the short-term respiratory health impact of this occupational exposure, which has never been described in the literature. Our research aims to: 1/ quantify the occupational exposure of taxi drivers to UFP, BC, oxides of carbon (CO, CO2) and to nitrogen dioxide (NO2), 2/ identify spatio-temporal variability and patterns of exposure related to occupational tasks, 3/ study the impact of this occupational exposure to UFP and BC on ventilation performances and respiratory symptoms.

Detailed Description
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The study is based on a random sampling of 100 taxi drivers, working full-time day shift, in Paris, members of three Trade Unions. It will be conducted over a period of two years in warm and cold season. The research will begin with an inclusion clinical examination. It consists on determining the overall health status of the participants by administering a standardized questionnaire and performing spirometry test, prick test and FENO measurement. The exposure assessment will be based on continuous measurement of UFP, BC, carbon monoxide (CO) and NO2, by portable devices during a working day (± 11 hours). On the same day, two spirometry tests and two measurements of exhaled carbon monoxide will be performed at the beginning and at the end of the shift, using handheld devices. Multivariate analysis will provide spatio-temporal distributions of individual exposures and their determinants. Generalized Estimating Equations (GEE) multivariate models will be used to determine the relation between exposure (UFP, BC) and respiratory symptoms, ventilation performances, adjusting for potential confounding/modifying factors.

Official Title
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Exposure of Taxi Drivers to Ultrafine Particles and Black Carbon Within Their Vehicles: Determinants of In-vehicle Exposure and Short Term Respiratory Impact.

Conditions
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Pulmonary Ventilation

Intervention / Treatment
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* Other: Exposure measurement
* Other: Spirometry test
* Diagnostic Test: Exhaled carbon monoxide test
* Diagnostic Test: Skin allergy test
* Diagnostic Test: Spirometry test
* Diagnostic Test: Fractional Exhaled Nitric Oxide Testing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 years Full time licensed taxi driver Subjects with more than 6 months of job tenure (as a taxi driver) Subjects affiliated to a social security scheme Subjects must have signed an informed consent and are willing to participate in the study Exclusion Criteria: Subjects having difficulty to understand the French language Subjects with less than 6 months of job tenure (as a taxi driver)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Exposure measurement|2 measurements per subject (in warm season and in cold season) Devices placed inside taxi vehicles on the passenger seat in a sampling bag|
|Other: Spirometry test|2 measurements per subject - before and after the work shift - in warm and cold seasons Subject will inhale and exhale in the device|
|Diagnostic Test: Exhaled carbon monoxide test|2 measurements per subject - before and after the work shift - in warm and cold seasons Subject will exhale in the device|
|Diagnostic Test: Skin allergy test|- Performed by a physician during the inclusion clinical examination|
|Diagnostic Test: Spirometry test|- Performed by a physician during the inclusion clinical examination|
|Diagnostic Test: Fractional Exhaled Nitric Oxide Testing|- Performed by a physician during the inclusion clinical examination|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean number of ultrafine fraction of particles (UFP) | per cm3 of air [from 1000 to 1000000 particles (pt)/cm3] - 8-11 h recording on 1 working day for each subject - repeated measurement in cold and warm seasons (6 months apart) | 6 months | 
| Mean concentration of black carbon (BC) | measurement of BC exposure concentrations per cubic meter (ng/m3) by the microAeth AE51 - 8-11 h recording on 1 working day for each subject - repeated measurement in cold and warm seasons (6 months apart) | 6 months | 
| Difference between the values of the forced vital capacity (FVC) measured before and after work shift | measurement of FVC in liters by a portable spirometer before and after the work shift according to procedures described by The European Respiratory Society and the American Thoracic Society (2005) - 2 measurements per subject - before and after the work shift - 1 working day Repeated measurement in cold and warm seasons (6 months apart) Overall period: 2 working days (one in each season) - 36 months | 36 months | 
| Difference between the values of the forced expiratory volume in one second (FEV1) measured before and after work shift | measurement of FEV1 in liters by a portable spirometer before and after the work shift according to procedures described by The European Respiratory Society and the American Thoracic Society (2005) -2 measurements per subject - before and after the work shift - 1 working day Repeated measurement in cold and warm seasons (6 months apart) Overall period: 2 working days (one in each season) - 36 months | 36 months | 
| Difference between the values of the forced expiratory flow between 25 and 75 % of FVC (FEF25-75) measured before and after work shift | measurement of FEF25-75 in liters by a portable spirometer before and after the work shift according to procedures described by The European Respiratory Society and the American Thoracic Society (2005). -2 measurements per subject - before and after the work shift - 1 working day Repeated measurement in cold and warm seasons (6 months apart) Overall period: 2 working days (one in each season) - 36 months | 36 months | 
| Difference between the rates of the peak expiratory flow (PEF) measured before and after work shift | measurement of PEF in liter per second (L.s-1) by a portable spirometer before and after the work shift according to procedures described by The European Respiratory Society and the American Thoracic Society (2005)-2 measurements per subject - before and after the work shift - 1 working day Repeated measurement in cold and warm seasons (6 months apart) Overall period: 2 working days (one in each season) - 36 months | 36 months | 
| Acute respiratory symptoms through self-administered questionnaire | by means of a self-completion questionnaire, participants report their acute respiratory symptoms felt during the measurement day - Reported before and after the work shift per subject - In cold and warm seasons (6 months apart)- Overall period: reported during 2 working days (one in each season) - 36 months | 36 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Characteristics of vehicles recorded by a self-administered questionnaire | fuel, age and type of the vehicle, air conditioning, air cabin filter reported by a self-administered questionnaire - after the work shift per subject - In cold and warm seasons (6 months apart) Overall period: reported during 2 working days (one in each season) - 36 months | 36 months | 
| Characteristics of the trips recorded by a self-administered questionnaire | speed, opened/closed windows, smoking, breaks, etc. reported by a self-administered questionnaire - after the work shift per subject - In cold and warm seasons (6 months apart) Overall period: reported during 2 working days (one in each season) - 36 months | 36 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ultrafine particles, black carbon, taxi drivers, respiratory function test, occupational exposure