Human Health Risk Assessment for Gasoline Exhaust

Prepared by: Fuels Assessment Section Water and Air Quality Bureau Healthy Environments and Consumer Safety Branch Health Canada November 2017

http://publications.gc.ca/collections/collection_2017/sc-hc/H144-52-2017-eng.pdf

Excerpt from Executive Summary

Gasoline, or spark ignition, engines are used throughout Canada, representing 92% of on-road vehicles and 87% of off-road engines or equipment. It is reasonable to assume that exposure to gasoline engine exhaust (GE) is nearly ubiquitous, particularly for Canadians living in urban areas or in close proximity to a major roadway: it is estimated that approximately 2 million people live within 50 m of a major road in Canada. GE is a highly variable and complex mixture of particulate and gaseous pollutants, the composition of which depends on numerous factors, including fuel quality, engine and pollution control technologies, vehicle operating conditions and ambient temperature. GE is an important source of criteria air contaminants (CACs) associated with adverse effects on human health, including fine particulate matter (PM2.5), ground-level ozone (O3), nitrogen dioxide (NO2), volatile organic compounds (VOCs) and carbon monoxide (CO). In addition, GE constituents include air toxics that are recognized internationally as carcinogens, such as benzene and polycyclic aromatic hydrocarbons (PAHs).

Gasoline fuel, vehicles and engines are subject to multiple federal regulations that have successfully reduced air pollutant emissions from gasoline mobile sources, representing a major success in the management of air quality in Canada and the protection of human health. However, given the number of vehicles and engines in use, the age structure of the in-use fleets, and the vehicle kilometres travelled by Canadians, gasoline engines remain a key source of air pollution. The adverse health effects of individual pollutants in GE or produced secondarily in the atmosphere from primary GE emissions (e.g. PM2.5, O3, NO2, benzene and PAHs), are well characterized in the scientific literature and include increased risk of cardiorespiratory mortality and morbidity and of cancer, among other outcomes.

This report is a comprehensive review and analysis of the potential adverse health effects associated with gasoline fuel use in Canada. Two distinct approaches are used. Part A provides an evaluation of scientific studies that have examined the health effects associated with exposure to GE as a mixture. Studies on the health effects of individual GE constituents, such as PM2.5 and benzene, were not considered, as these substances have been extensively reviewed by Health Canada elsewhere. Part B provides a quantitative assessment of the contribution of on-road and off-road gasoline mobile source emissions to individual air pollutant concentrations in Canada and the population health impacts associated with that incremental contribution. The health impact analysis in Part B, which is based on well-established quantitative estimates of risk of adverse health impacts associated with incremental changes in air concentrations of individual pollutants, is complementary to the traditional risk assessment approach presented in Part A.

The Canadian Urban Environmental Health Research Consortium – a protocol for building a national environmental exposure data platform for integrated analyses of urban form and health

Jeffrey R. Brook, Eleanor M. Setton, Evan Seed, Mahdi Shooshtari, Dany Doiron and CANUE – The Canadian Urban Environmental Health Research Consortium

BMC Public Health BMC series https://doi.org/10.1186/s12889-017-5001-5 Published: 8 January 2018

Abstract

Background

Multiple external environmental exposures related to residential location and urban form including, air pollutants, noise, greenness, and walkability have been linked to health impacts or benefits. The Canadian Urban Environmental Health Research Consortium (CANUE) was established to facilitate the linkage of extensive geospatial exposure data to existing Canadian cohorts and administrative health data holdings. We hypothesize that this linkage will enable investigators to test a variety of their own hypotheses related to the interdependent associations of built environment features with diverse health outcomes encompassed by the cohorts and administrative data.

Respiratory and cardiovascular responses to walking down a traffic-polluted road compared with walking in a traffic-free area in participants aged 60 years and older with chronic lung or heart disease and age-matched healthy controls: a randomised, crossover study

Rudy Sinharay, MBBS^†, Jicheng Gong, PhD^†, Benjamin Barratt, PhD, Pamela Ohman-Strickland, PhD, Sabine Ernst, MD, Prof Frank Kelly, PhD, Prof Junfeng (Jim) Zhang, PhD, Prof Peter Collins, MD, Prof Paul Cullinan, MD, Prof Kian Fan Chung, DSc

^†Co-first authors contributed equally

The Lancet.  DOI: http://dx.doi.org/10.1016/S0140-6736(17)32643-0 Published: 05 December 2017

Summary

Long-term exposure to pollution can lead to an increase in the rate of decline of lung function, especially in older individuals and in those with chronic obstructive pulmonary disease (COPD), whereas shorter-term exposure at higher pollution levels has been implicated in causing excess deaths from ischaemic heart disease and exacerbations of COPD. We aimed to assess the effects on respiratory and cardiovascular responses of walking down a busy street with high levels of pollution compared with walking in a traffic-free area with lower pollution levels in older adults.

Evaluation of daily time spent in transportation and traffic-influenced microenvironments by urban Canadians

Carlyn J. Matz ,David M. Stieb, Marika Egyed, Orly Brion, Markey Johnson

Air Quality, Atmosphere & Health pp 1–12|  First Online: 30 November 2017 https://doi.org/10.1007/s11869-017-0532-6

Abstract

Exposure to traffic and traffic-related air pollution is associated with a wide array of health effects. Time spent in a vehicle, in active transportation, along roadsides, and in close proximity to traffic can substantially contribute to daily exposure to air pollutants. For this study, we evaluated daily time spent in transportation and traffic-influenced microenvironments by urban Canadians using the Canadian Human Activity Pattern Survey (CHAPS) 2 results. Approximately 4–7% of daily time was spent in on- or near-road locations, mainly associated with being in a vehicle and smaller contributions from active transportation. Indoor microenvironments can be impacted by traffic emissions, especially when located near major roadways. Over 60% of the target population reported living within one block of a roadway with moderate to heavy traffic, which was variable with income level and city, and confirmed based on elevated NO₂ exposure estimated using land use regression. Furthermore, over 55% of the target population ≤ 18 years reported attending a school or daycare in close proximity to moderate to heavy traffic, and little variation was observed based on income or city. The results underline the importance of traffic emissions as a major source of exposure in Canadian urban centers, given the time spent in traffic-influenced microenvironments.