Toronto Subway Air Quality Health Impact Assessment Prepared for: Toronto Public Health City of Toronto November 15, 2019 Toronto Subway Air Quality Health Impact Assessment Project Summary Introduction Toronto’s subway is a critical part of the Toronto Transit Commission’s (TTC) public transportation network. First opened in 1954, it spans over 77 km of track and 75 stations across the city. On an average weekday over 1,400,000 customer-trips are taken on the subway. In 2017, Health Canada reported levels of air pollution in the TTC subway system that were elevated compared with outdoor air. The Toronto Board of Health requested that Toronto Public Health (TPH) oversee an independent study to understand the potential health impacts of air quality issues for passengers in the Toronto subway system - The Toronto Subway Air Quality Health Impact Assessment (TSAQ HIA). The TSAQ HIA takes a holistic approach to assessing how subway use may positively and/or negatively impact the health and well-being of Torontonians. The HIA used a human health risk assessment (HHRA) approach to calculate the potential health risks from exposure to air pollutants in the subway, and the results of the HHRA were incorporated into the HIA. The TSAQ HIA sought to answer three overarching questions: 1. What is the potential health risk to current passengers from air pollutants in the subway system? 2. What are the potential health benefits to mitigation measures that could be implemented to improve air quality in the TTC subway system? 3. What is the overall impact of the TTC’s subway system on the health and well-being of Torontonians? Results of the Toronto Subway Air Qualty Health Impact Assessment The TSAQ HIA assessed the overall impact of subway use on the health and well-being of Torontonians. The TSAQ HHRA calculated the potential health risks from exposure to fine particulate matter (PM2.5) and associated metals for people who regularly use Toronto’s subway system. The following are the conclusions of the TSAQ HIA based on the three overarching study questions posed. Toronto Subway Air Quality Health Impact Assessment i 1. What is the potential health risk to current passengers from air pollutants in the subway system? There have been three monitoring campaigns that have measured airborne concentrations of chemicals in Toronto’s subway system (Van Ryswyk, 2017; TTC, 2019; and Health Canada, 2019). They all indicate that there are elevated concentrations of fine particulate matter (PM2.5) and some metals on subway station platforms and on the trains, as compared to levels found in Toronto’s outdoor air. Long-term exposure to subway air quality increases an individual's overall annual PM2.5 exposure by 5% to 33%. The levels of some metals result in predicted cancer risk above Canadian health authorities risk objectives at times. Short-term exposures to subway air quality, particularly on Line 2, may on occasion, result in transient (i.e., short-lived; passing; not permanent) respiratory symptoms (i.e., coughing, shortness of breath, chest tightness, general asthmatic symptoms) and/or a temporary decline in lung function for children and adults with asthma, adults with chronic obstructive pulmonary disease (COPD), and perhaps even healthy adults. It was also determined that the levels of PM2.5 and associated metals measured in the Toronto subway system were similar to those found in London’s Underground system in the United Kingdom and in subway systems across Europe. Overall, the results of the TSAQ HHRA indicate that the levels of PM2.5 are high enough to warrant mitigation, particularly on Line 2. Any reduction in PM2.5 platform concentrations would also lower concentrations of associated metals. 2. What are the potential health benefits to mitigation measures that could be implemented to improve air quality in the TTC subway system? Fine particulate matter (PM2.5) is a non-threshold contaminant, meaning that there is some potential for health impact at all levels of exposure. The available research has indicated that although the composition of subway PM2.5 is different than that found in outdoor air, its health effects could be similar. The Canadian Council of Ministers of the Environment (CCME) set Canadian Ambient Air Quality Standards (CAAQs) for PM2.5 that uses a continuous improvement philosophy to lower the concentrations in outdoor air. In other words, any decrease in PM2.5 exposure would result in better health outcomes for those exposed. Similarly, the results of the TSAQ HHRA cannot provide a specific target of PM2.5 to achieve negligible health risk, given that it is likely a non-threshold contaminant. Rather, it is clear that Line 2 PM2.5 concentrations are the highest in the subway system and efforts should be made to lower them. Line 1 Toronto Subway Air Quality Health Impact Assessment ii concentrations are also elevated as compared with outdoor air and as such, a continuous improvement approach to lowering them should be taken. Any decrease in PM2.5 levels within Toronto’s subway would also improve potential health risks of associated metals. 3. What is the overall impact of the TTC’s subway system on the health and well-being of Torontonians? The HIA’s assessment of the other environmental and social determinants of health concluded that there are numerous benefits to people’s health and well- being from taking the subway. It provides a safer alternative to driving, reduces outdoor air pollution and greenhouse gases, promotes physical activity and provides better access to employment, schooling and social/community services. Each individual reacts differently to air pollution. Children, seniors and those with heart or lung disease are most sensitive to adverse health effects of air pollution. While mitigation measures are being considered, concerned individuals should self-monitor in determining whether being in the subway is affecting them and decide what mode of transportation best meets their needs at any given time. Recommendations Overall, access to the subway system provides a number of positive health benefits to its users. The City of Toronto should continue to encourage the use of the subway, especially as an alternative to personal vehicles, and seek to expand the system to provide greater access to all Torontonians. A Particulate Matter Reduction Strategy that includes both short and long term measures to improve air quality in the subway is recommended. Further, to reduce the uncertainty in the HHRA it would be beneficial to determine the form of chromium in PM2.5. Although the limited research in the field suggests subway air quality health effects may not be clinically significant, further personal exposure research should be undertaken to reduce the uncertainties identified in the HHRA and to better understand the potential health impacts to Toronto subway users. TPH is encouraged to monitor the scientific literature in this field and continue contact with other health authorities, such as the United Kingdom's Committee on the Medical Effects of Air Pollutants (COMEAP), to determine how new research findings can be applied to Toronto’s subway system. Toronto Subway Air Quality Health Impact Assessment iii Table of Contents 1 INTRODUCTION .............................................................................................. 1 1.1 Scope of the Investigation of the Toronto Subway Air Quality Health Impact Assessment .......................................................................................... 2 2 Toronto Subway System ............................................................................... 4 2.1 Toronto Subway Trains ........................................................................... 5 2.2 Use of the Toronto Subway System ....................................................... 6 2.3 Air Quality Studies Conducted in the Toronto Subway System .......... 7 2.3.1 Urban Transportation Exposure Study (UTES) 2010 to 2013 .............. 7 2.3.2 Toronto Transit Commission Subway Air Quality Study 2017 – 2018 .. 8 2.3.3 Subway Air Quality Initiative (SAQI) 2017-2018 ................................... 9 3 HEALTH IMPACT ASSESSMENT METHODOLOGY .................................. 11 3.1 Steps of an HIA ....................................................................................... 12 3.2 Health Equity .......................................................................................... 13 3.3 Stakeholder Engagement ...................................................................... 15 4 SCREENING .................................................................................................. 15 5 SCOPING ....................................................................................................... 15 5.1 Scope Overview ..................................................................................... 15 5.1.1 The Goal and Anticipated Use of the HIA ........................................... 15 5.1.2 The HIA Team and Roles and Responsibilities .................................. 16 5.1.3 Stakeholder Engagement ................................................................... 16 5.2 Selection of the TSAQ HIA Determinants of Health ............................ 17 5.2.1 Environmental Factors ........................................................................ 17 5.2.2 Social, Economic and Other Factors .................................................. 17 5.3 Temporal and Geographic Boundaries ................................................ 18 5.3.1