Diesel Engine Exhaust

Prevalence Estimate

Results show that approximately 804,000 Canadians are occupationally exposed to diesel engine exhaust; 92% of these workers are male. This accounts for nearly 5% of the working population in Canada. The largest industrial groups exposed to diesel engine exhaust are truck transportation and auto repair and maintenance.

When exposure is examined by occupation, the largest exposed groups are truck drivers (303,000 people exposed), bus drivers (78,000 exposed), and heavy equipment operators (77,000 exposed). Other common groups include couriers, landscaping labourers, and taxi drivers.

Data Sources & Methods

Data Sources

Data used in developing the occupational estimates for diesel engine exhaust were collected from several sources:

1. Canadian and US scientific peer reviewed publications that addressed diesel engine exhaust exposure in Canada and the United States.
2. Grey literature including technical reports from governments and international bodies.

Prevalence Estimate Method

CAREX defines exposure to diesel engine exhaust as inhalation exposure at work above the levels expected in the general environment (i.e. from living close to a highway).

To determine the number of workers potentially exposed to diesel engine exhaust at work, CAREX occupational exposure experts used methods previously established in other peer-reviewed CAREX projects in Europe. A series of steps were taken to assign exposure proportions to occupations and industries at risk of exposure to diesel engine exhaust.

1. Occupations and industries at risk of possible exposure to diesel engine exhaust were identified using any combination of data sources described above.
2. The total number of workers in each identified occupation and industry intersection was obtained from Statistics Canada 2006 census data.
3. A percentage of workers exposed was assigned to that occupation and industry intersection. Percentages were determined by consultation with existing evidence in the data sources, previously established methods from the Europe CAREX estimates and the expert judgement of CAREX occupational hygienists.
4. The number of workers in the identified group is multiplied by the assigned percentage to calculate the prevalence estimate of workers exposed to diesel engine exhaust.