Cities, Climate and Inequalities

Clearing the air: Barriers to improving air quality and reducing environmental inequity along Vancouver’s Clark-Knight corridor truck route

March 2024

Nancy Lai-Chu Chan, SFU, Masters of Urban Studies


Based on a thesis completed for the Masters of Urban Studies program at Simon Fraser University, this research summary focuses on the investigation of barriers to implementing policies and programs to improve air quality and reduce environmental inequity related to traffic-related air pollution (TRAP) exposure along the Clark-Knight corridor, home to a six-lane arterial road and one of the busiest, most polluted truck routes in the Metro Vancouver region (Metro Vancouver, 2017; Metro Vancouver, 2018; Metro Vancouver, 2019; Wang et al., 2018). Exposure to the increased health hazards of TRAP along this corridor is inequitable insofar that it affects visible minority groups, children and lower income populations more so than other segments of the population (City of Vancouver, 2022; Statistics Canada, 2016). As we experience more extreme heat events due to climate change, the interacting and compounding effects of air pollution, heat and urban density can be expected to intensify and lead to higher mortality rates. Despite these known risks, planning practices and policies continue to allow residential densification along busy truck routes, particularly for rental and below-market housing. At the same time, the Province of British Columbia and Metro Vancouver have stalled their attempts to address air pollutant emissions from heavy-duty diesel trucks that are older and poorly maintained or whose emissions control systems have been illegally tampered with.

This qualitative, mixed-methods case study approach features a primary case study on the Clark-Knight corridor as well as a secondary contrast case on the Province of Ontario’s DriveON Emissions and Safety Inspection Program. The findings lead to insights about: the impacts of planning decisions that have increased truck traffic volumes and residential density along the corridor; the trucking industry’s lobby efforts and how the Province of British Columbia’s prioritization of greenhouse house gas emissions reductions have inhibited policy innovation and the ratification of stricter policies to manage air pollutant emissions from trucks in British Columbia. Findings also underscore the importance of mitigating climate change through both reducing greenhouse gas emissions and improving air quality.

State of the scientific literature on the action modality studied

To contextualize the research and guide data collection, a conceptual framework was developed based on the following three bodies of literature: 1) the health impacts of TRAP exposure; 2) environmental inequity related to TRAP in Canada; and 3) the need for a paradigm shift towards sustainable transportation practices where goods can be moved through the road network without causing harm to human health or the environment. These areas of literature show that a problem exists and why change is needed.  

Up to 74 percent of Vancouverites live within TRAP exposure zones, meaning that they live within 250 meters of a major urban road or within a 500-meter range of a highway (Brauer et al., 2013; Southern Ontario Centre for Atmospheric Aerosol Research, 2019). According to population health researchers and government agencies, breathing in this polluted air has negative health impacts related to respiratory health, pregnancy outcomes, cardiovascular disease, cancer, new onset cases of asthma in children, and mental health issues (Carey et al., 2018; Ho et al., 2018; Zhang et al., 2018; Braithwaite et al., 2019; Brauer et al., 2019; Health Canada, 2019). There is also “no evidence of an exposure threshold: that is, any incremental increase in air pollutant concentration is associated with an increased risk of adverse health outcomes” (Health Canada, 2019, p. 6). According to Health Canada, annual premature deaths attributable to exposure to air pollution in Canada hovers around 15,300 people, or 42 deaths per 100,000 people, an estimate that other sources even consider to be understated (Health Canada, 2021; Anonymous Informant B). As the impacts of climate change intensify, so too will heat waves and air stagnation, which are conditions that worsen air quality and increase ozone exposure (Climate Change, Air Contaminants, and Your HealthCanada.Ca, n.d., para 5; Pfister et al., 2014; Canadian Association of Physicians for the Environment, 2021). Ground-level ozone, which is created when TRAP reacts with sunlight and heat, is known to cause acute respiratory, cardiovascular and central nervous system impacts as well as an “increased number of cardiopulmonary-related deaths” (Metro Vancouver, 2014, p. 14). During the 2021 heatwave, British Columbia recorded 815 sudden deaths, 610 of which were deemed as heat-related (British Columbia Coroners Service, 2022). Although no study to date has analyzed how many of those sudden deaths can be attributed to air pollution, data on the causes of death during the 2003 European heat waves show that heat, poor air quality and ozone exposure are a deadly mix (Climate Change, Air Contaminants, and Your HealthCanada.Ca, n.d.; Garcia-Herrera et al., 2010).

Research has also shown that TRAP exposure in Vancouver is inequitable. This strand of research, which refers to the inequitable exposure to environmental harms and benefits as environmental racism, environmental injustice or environmental inequality, “promotes the concept that environmental harms and environmental benefits should be equality distributed, without discrimination on the basis of socio-economic status, race, ethnic origin, or residence on a First Nations reserve” (Mitchell and D’Onofrio, 2016, p. 307‒308). This present study drew on research conducted by Amram et al. (2010), Doiron et al. (2020), Kirby-McGregor et al. (2023) and Su et al. (2010) to help frame what seemed unfair and confirm that inequitable exposure to TRAP exists in Canada. According to Amran et al. (2010), in Vancouver, schools located in lower-income neighbourhoods were more likely to be located in a TRAP exposure zone. And according to Dorion et al. (2020), areas of lower socioeconomic status were 23 percent more likely to experience high TRAP exposure and 57 percent less likely to have high urban greenery when compared to city-wide averages. This latter study is particularly relevant as its spatial data reveals clusters of areas along the Clark-Knight corridor as being high in material deprivation, low in greenness and high in TRAP. Together, these findings align with air quality data coming from other sources that identifies the corridor as having consistently higher levels of air pollutants due to influence from traffic emissions, particularly from older, heavy-duty diesel trucks (Doiron et al., 2020; Metro Vancouver, 2017; Metro Vancouver, 2018; Metro Vancouver, 2019; Southern Ontario Centre for Atmospheric Aerosol Research, 2019; Wang et al., 2018). 

Another body of literature that informed this study focuses on a paradigm shift towards sustainable transportation practices. This provided a lens to assess whether policymaking and planning processes occurring in British Columbia are sustainable and helped identify opportunities for change. Markers of an unsustainable business-as-usual approach to transportation planning includes a tendency for things to occur in silos “disconnected from environmental and social planning areas” and a lack of consideration for “environmental and social equity impacts,” which stems from a “lack of integrated planning, flawed policy-making and excluding effective public participation” (Schiller & Kenworthy, 2017, p. 3, 14, 252). A shift towards a new paradigm to make trucking and transportation practices more sustainable could be accomplished through integrated and coordinated policymaking; making goods movement practices more efficient through land-use solutions or increased use of other transportation modes; and the regeneration, repair and renewal of what has been degraded (Schiller & Kenworthy, 2017). The academic literature also stresses that meaningful engagement with a diverse range of stakeholders, including people who live along truck routes, is needed to better balance private and public interests (Cui, Dodson & Hall, 2015; Knoepfel, Grant & Perl, 1999).

Original research case, methodology and data 

To identify the barriers to implementing policies and programs to improve air quality and reduce environmental inequity related to TRAP exposure along the Clark-Knight corridor, this study employed a qualitative, mixed-methods case study approach. A secondary contrast case on the Province of Ontario’s DriveON Emissions and Safety Inspection Program served to disprove the conclusion reached by some in the case of the Clark-Knight corridor that policy barriers to sustainable mobility could not be overcome, hence condoning the inhibiting barriers that were identified to exist in British Columbia. 

An analysis of government documents, news media coverage, and semi-structured interviews with key informants was conducted. For the Clark-Knight corridor case, documents from 2003 to 2022 were reviewed, including air quality strategies, community plans, transportation plans, and regional land use plans. Similarly, news media articles were analyzed to capture community concerns, political dynamics and governmental efforts to address air quality. For the Ontario contrast case, the study reviewed media releases issued by the Government of Ontario and the Ontario Trucking Association between 2018 to 2020 that mentioned work to reduce emissions from heavy-duty diesel trucks along with program information on their website.

A total of 16 semi-structured interviews were conducted: 12 with key informants who have previously worked or currently work within different levels of government or government agencies in British Columbia; one with a resident who lives within 250 meters of the Clark-Knight corridor; one with a citizen scientist volunteer who is working to actively improve air quality along the corridor; one with a representative from the British Columbia Trucking Association; and one with a representative from the Ontario Trucking Association. 

This study also applied principles derived from Schiller & Kenworthy (2017) pertaining to sustainable transportation and urban mobility policymaking in order to assess opportunities and policy practices for making planning and policymaking more sustainable. Finally, to better understand barriers to policy innovation, this study also drew on Harrison’s (1996) work, which explained the role of electoral incentives in a democratic government’s process of deciding whether or not to pursue more stringent environmental policies.


While there is extensive research related to the use of private automobiles, public transportation and active transportation, a knowledge gap exists regarding how urban freight transport intersects with “transport planning, land-use and wider urban planning” (Cui, Dodson & Hall, 2015, p. 2). This study fills a gap related to the institutional landscape and state of sustainable planning and policy practices related to urban planning and freight movement within a Canadian context. Findings fell within two categories: 1) planning decisions that increased truck traffic volumes and residential density along the Clark-Knight corridor; and 2) political factors that inhibited policy innovation and the ratification of stricter environmental policies for heavy-duty diesel trucks in British Columbia. 

1) Planning decisions that increased truck traffic volumes and residential density

Based on this study’s analysis of land use and transportation planning decisions surrounding the Clark-Knight corridor, decisions related to industrial land supply, zoning for residential areas, truck routes, port growth and planning decisions from various levels of government reinforce environmental inequity. The findings highlight how pressures on a limited land base can create ripple effects and barriers to more sustainable approaches to planning; specifically, constrained land supply in the region and pressures on industrial land. 

The conversion of industrial land for housing and commercial use, along with growth in demand has pushed the industrial land vacancy rate down to near 0 percent. This, in turn, has engendered the urban sprawl of logistics operations, resulting in trucks having to travel farther distances through urban neighbourhoods with less direct routes (Vancouver Fraser Port Authority, n.d.; Business in Vancouver, 2021; CBRE, 2021). Metro Vancouver and the port authority both attribute this state of affairs to a fractured regulatory landscape, overlapping jurisdictions, competition between municipalities and a “lack of collaboration and coordination between government agencies” (Metro Vancouver, 2020, p. 25; Vancouver Fraser Port Authority, 2020). An additional contributing factor is the intensification of trade through the Port of Vancouver, particularly through container terminals located on the south shore of the Burrard Inlet. Two recently launched expansion projects at Centerm and Vanterm Container Terminals are expected to lead to at least 53 percent more container truck traffic along the Clark-Knight corridor (Vancouver Fraser Port Authority, 2016). 

Figure 1. Locations of Centerm and Vanterm container terminals.
Adapted from VanMap by City of Vancouver, n.d. 

Yet why, we might ask, is growth so intensely concentrated along the Clark-Knight corridor? According to interviewees, there is no other place to accommodate more shipping containers in the region (Anonymous informant E; Vancouver Fraser Port Authority, 2020). Opposition to heavy-duty truck traffic from residents of Nanaimo Street, a municipal truck route that runs adjacent to the Clark-Knight corridor was also a factor. In response to this opposition during a municipal election year, the City of Vancouver and the port authority launched an initiative to restrict and concentrate port-destined container trucks to truck routes within the TransLink’s regional Major Roads Network (MRN) (Vancouver is Awesome, 2011; Vancouver is Awesome, 2012; CBC News, 2011; CTV News, 2011; Hall, 2015).

Figure 2. The major road network, provincial highways and municipal road networks (in the City of Vancouver). (Translink, 2017, p. 14)

While this restriction provided relief for Nanaimo Street residents, it led to a loss of environmental quality for Clark-Knight corridor residents: with the diversion, trucks were spending at least 15 more minutes on Clark-Knight, releasing more greenhouse gases and air pollutants, and generating more truck traffic. However, while elected officials acknowledged that we cannot keep shifting the problem (CBC News, 2011), there was no organized opposition among corridor residents to counteract the diversion (Hall, 2015). 

Another barrier to reducing inequitable exposure is the existence of policies that encourage housing densification along arterial roads. Specifically, the City of Vancouver’s Secure Rental Policy now allows for rental housing buildings of up to six storeys along arteries that are currently zoned for low-density residential uses as well as buildings of up to four storeys one block in on either side of these arteries (City of Vancouver, 2022). While this promises to increase the stock of affordable rental housing options, it will also draw even more people to live within TRAP exposure zones along arterial roads. In addition, it will attract a higher proportion of lower income people to live along these arteries, as these are the people who rely on affordable and below-market housing (City of Vancouver, 2022b). 

 According to Statistics Canada census data, the Clark-Knight corridor is home to higher proportions of visible minority groups, toddlers, renters and lower income populations. As a result, the negative impacts of decisions related to trade growth, land use and transportation planning in this area reinforce and intensify inequitable exposure to air pollution (Statistics Canada, 2016).

Figure 3. Concentration of visible minority residents in the City of Vancouver. (Statistics Canada, 2016)

Figure 4. Toddlers per square kilometer in the City of Vancouver. (Statistics Canada, 2016)

2) Political factors that inhibited policy innovation and the ratification of stricter environmental policies

To make sense of the political dynamics at play and the failed attempts by various government agencies to ratify policies that address air pollutant emissions from heavy-duty trucks, this research draws on Harrison’s (1996) assessment of the federal and provincial role in the development of Canadian environmental policy. Specifically, this researcher highlights that while environmental regulation delivers widespread benefits, it generally does so at a concentrated cost on industry, a group that is more likely to organize effective opposition to such regulations. For example, industry is, by and large, better able to make campaign contributions and contribute to job creation, as a result of which politicians are generally eager to keep them onside. Meanwhile, the public, who are the main beneficiaries of environmental regulation, can hardly offer similar perks to the political arena and are generally unaware of the benefits, to themselves, of increased regulation. This combination of limited public attention to environmental issues and strong opposition from potentially regulated industries yields significant political costs and limited political benefitsa recipe for government reluctance to impose environmental regulations (Harrison, 1996).

The trucking industry’s history of lobbying efforts and strike action in British Columbia have been successful in:

  • shifting the provincial government’s focus from mandatory programs to voluntary incentive programs that increase fuel efficiency; 
  • delaying the implementation of the port authority’s truck age requirement by more than  5 years; 
  • shifting the port authority’s requirement for trucks to be no more than 10 years old to being no more than 12 years old; and
  • interfering with Metro Vancouver’s efforts laid out in their Clean Air Plan to reduce TRAP from heavy-duty diesel trucks.

The looming threat of strike action, likely to halt the national economy, was instrumental to this success. According to anonymous informants, the trucking industry was also able to persuade the Province of British Columbia to abstain from addressing illegal emissions system tampering, namely with the argument that this would reveal higher actual fuel use (and thus greenhouse gas emissions) and, as a result, that climate action targets are being missed by an even wider margin (Anonymous Informant F, Anonymous Informant G). To date, voluntary measures for heavy-duty diesel trucks focus on reducing fuel use and costs for truckers. Key informants also pointed to siloed decision-making as a contributing factor, explaining that initiatives tended to lose their thrust and disappear whenever they were passed on to another government department (Anonymous Informant G, Anonymous Informant I).

 While British Columbia has no measure in place for ensuring that high-polluting diesel trucks get taken off the road or are properly maintained for lower pollutant emissions, the Province of Ontario has an integrated mandatory emissions and safety inspection program for heavy-duty diesel trucks. In effect since June 2021, the program includes anti-emissions control system tampering checks for all trucks and emissions testing for trucks seven years or older (Government of Ontario, 2018; Government of Ontario, 2019). The successful implementation of this program is attributed to factors such as:

  • A lack of industry pushback; in fact, the Ontario Trucking Association lobbied for such a program as a way to counteract cost undercutting enabled by illegal emissions system tampering within its own industry.
  • The Province of Ontario saw it as a win-win situation; the province sought to push back on the federal carbon tax and thus welcomes made-in-Ontario ways to address air quality and climate change.
  • Industry fear of municipal efforts to reroute truck routes due to air quality concerns, which could create inefficient routes. 

Based on Harrison’s work, in the case of Ontario, the provincial government was able to position itself as being supportive of industry and the environment and as being responsive to air quality concerns raised by municipalities and Ontario residents—a win-win situation. The program also allowed the government to “diffuse benefits on the public” without the usually anticipated political backlash in the form of organized opposition from industry to regulation (Harrison, 1996, p. 13).

Findings of this study clearly show how land use and transportation planning practices can reinforce environmental inequity, and how political barriers such as a lack of electoral incentives and industry lobbying can inhibit policy innovation and the ratification of stricter environmental policies for heavy-duty diesel trucks in British Columbia. 


As Metro Vancouver’s population grows, it is imperative that we work to ensure growth does not come at the cost of the health and wellbeing of communities. This study’s findings underscore the need for action across all levels of government and industry to take a bold stance on improving air quality and reducing environmental inequity along not only the Clark-Knight corridor but also other truck routes and major arterial roads in the region. Although there is a widespread political desire to increase housing supply so as to accommodate more residents and make housing more affordable, projects to improve air quality along arterial roads and truck routes must coincide with plans to increase residential density and mitigate against the impacts of climate change.

Based on the findings and observations, this study proposes the following policy recommendations: 

  • the development of a nation-wide emissions testing program to counteract poor maintenance and tampering of all heavy-duty diesel trucks;
  • aggressive incentives, subsidies and targets to stimulate technological breakthroughs, innovation and a transition to heavy-duty zero emission vehicles;
  • work with health authorities and the BC Centre for Disease Control to adopt a shared understanding and framework of health equity to assess actions and inactions;
  • short-term TRAP exposure mitigation by planting hedges alongside arteries; and
  • complementing the existing requirement that large new buildings include air filtration systems with the requirement to retrofit the air filtration systems of already existing residences along arteries.

Areas of future research could include the feasibility of using waterways for goods movement, the reduction of truck traffic within a Metro Vancouver context, the true death toll from poor air quality in Canada and updated research on the impacts of emissions control system tampering.

To cite this article

Chan, N. (2024). Clearing the air: Barriers to improving air quality and reducing environmental inequity along Vancouver’s Clark-Knight corridor truck route. In Cities, Climate and Inequalities Collection. VRM – Villes Régions Monde.

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