Data and publications on MCS
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Data and Publications on Multiple Chemical Sensitivity (MCS)
Evidence supporting ASEQ-EHAQ’s Québec Election 2026 priorities
This page brings together selected Canadian data, ASEQ-EHAQ research, reports and peer-reviewed publications relevant to Multiple Chemical Sensitivity (MCS), accessibility and public policy. It is intended as a concise evidence resource for decision-makers, candidates, organizations, journalists and members of the public.
MCS in Canada: how many people are affected?
Prevalence of Multiple Chemical Sensitivity in Canada Between 2000 and 2020
This peer-reviewed study examined 20 years of Canadian Community Health Survey (Statistics Canada) data to assess changes in diagnosed MCS prevalence in Canada. Reported diagnosed MCS increased from 1.8% in 2000–2001 to 3.5% in 2020, demonstrating that MCS affects a substantial and growing number of people in Canada.
Published: International Journal of Environmental Research and Public Health, 2026, 23(2), 236. https://doi.org/10.3390/ijerph23020236
Preliminary 2025 Canadian Community Health Survey data indicate that 9.4% of Canadian adults report MCS — approximately 3.1 million people. The prevalence is substantially higher among women: 12.8% of women report MCS, compared with 5.9% of men. Approximately 900,100 adults, or 2.7%, report having been diagnosed with MCS.
Resource: ASEQ-EHAQ — MCS Statistics.https://aseq-ehaq.ca/en/mcs-statistics/
https://aseq-ehaq.ca/wp-content/uploads/2026/06/2025-Statistics-Canada-MCS-Data_june.pdf
Accessibility and lived experience
Fragrance-Free Policies in Practice: Identifying Perceived Implementation Gaps Through Lived Experience in a Qualitative-Dominant Mixed-Methods Study
This 2026 peer-reviewed study examined accessibility barriers and the lived experience of fragrance-free policies among 60 participants across ten focus groups. Participants described continuing barriers in workplaces, healthcare settings and other public environments, including gaps in implementation, enforcement, education and accommodation.
Published: International Journal of Environmental Research and Public Health, 2026, 23(8), 1077. https://doi.org/10.3390/ijerph23081077
Accommodation and socioeconomic barriers
When Disability Recognition Fails: Accommodation Refusals and Socioeconomic Challenges Among Canadians with Multiple Chemical Sensitivity
This 2026 peer-reviewed publication examines accommodation refusals and socioeconomic challenges experienced by Canadians living with MCS. It supports the need for clearer accommodation pathways, disability recognition and measures that prevent environmental barriers from excluding people from employment, services and participation.
Published: International Journal of Environmental Research and Public Health, 2026, 23(8), 1076. https://doi.org/10.3390/ijerph23081076
Healthcare access
Healthcare Access for Adults with Multiple Chemical Sensitivity in Canada: A Cross-sectional Survey
This 2026 peer-reviewed study examined healthcare access among Canadian adults with MCS. Participants reported barriers associated with fragranced and disinfectant products in healthcare settings, as well as difficulties related to access and accommodation. The findings support practical measures to reduce exposure-related barriers and improve accessibility in healthcare.
Published: International Journal of Environmental Research and Public Health, 2026, 23(9), 1193. https://doi.org/10.3390/ijerph23091193
Chemical exposures and symptom provocation
Self-Reported Chemical Exposures at Onset and Symptom Provocation in Adults with Multiple Chemical Sensitivity: A Descriptive Cross-Sectional Survey
In this 2026 peer-reviewed study of 119 Canadian adults with MCS, participants most frequently identified fragranced products, air fresheners, cleaning products, disinfectants, construction materials and laundry products among exposures associated with onset or subsequent symptom provocation. The study highlights the importance of exposure reduction and source-control approaches in public policy and accessibility.
Published: International Journal of Environmental Research and Public Health, 2026, 23(9), 1092. https://doi.org/10.3390/ijerph23091092
Accessible indoor air and source control
Accessible Indoor Air in the Built Environment — Research Report
ASEQ-EHAQ’s real-world indoor air quality research compared workplaces with fragrance/scent-free policies with workplaces without such policies. The research found substantially lower total volatile organic compound (TVOC) concentrations in policy environments, with an approximately 70% reduction overall. The research also found that source control and ventilation address different pollutant sources; for some product-derived VOCs, substantially greater ventilation would be required to produce reductions comparable to source-control measures.
The report also documents product-testing and policy-implementation findings, reinforcing that fragrance-free labelling alone does not necessarily mean emission-free and that procurement, training, implementation and accountability matter.
Published by ASEQ-EHAQ, 2026. Research funded by Accessibility Standards Canada. https://aseq-ehaq.ca/en/executive-summary-report-iaq/
Fragrance-free policy evidence
Fragrance-Free Policies: A Scoping Review of Definitions, Implementation, and Gaps
This 2026 peer-reviewed scoping review examined 63 fragrance-free policies and guidance documents across workplaces, healthcare, education and public settings. It found substantial variation in definitions, scope, enforcement and implementation. Many policies relied heavily on voluntary compliance, while structural supports such as procurement controls, staff training, facilities integration and evaluation were less consistently included.
The findings support stronger policy design with clear definitions, institutional responsibility, source-control measures, accommodation pathways, education and accountability.
Published: International Journal of Environmental Research and Public Health, 2026, 23(8), 1089. https://doi.org/10.3390/ijerph23081089
Scent-free policy resources in Canada
ASEQ-EHAQ Database of Scent-Free Policies in Canada
ASEQ-EHAQ maintains a database of scent-free and fragrance-free policies and practices identified across Canada, including healthcare, government, workplace, educational and community settings. The database demonstrates that fragrance-reduction measures are already used by many Canadian institutions and provides examples that can inform policy development.
https://aseq-ehaq.ca/en/database-of-scent-free-policies-in-canada/
Employment and socioeconomic impact
ASEQ-EHAQ has compiled Canadian data on employment, income, missed work, unmet needs and other socioeconomic consequences associated with MCS. These data show that MCS can have serious consequences for workforce participation and economic security despite comparable or higher levels of education among many affected people.
ASEQ-EHAQ’s 2026 Socioeconomic Impact report https://aseq-ehaq.ca/wp-content/uploads/2026/08/Socioeconomic-Impact-of-MCS-in-Canada.pdf
Website resource: ASEQ-EHAQ MCS Statistics. https://aseq-ehaq.ca/en/mcs-statistics/
Housing and the built environment
Accessible housing is a critical issue for people with MCS because exposures can arise from neighbouring units, common areas, cleaning and maintenance products, pesticides, renovation materials, new furnishings and building materials. ASEQ-EHAQ’s built-environment work supports source control, lowest-emission materials and products, fragrance-free practices and the development of housing that can meet MCS-related accessibility requirements.
Website resource: https://ecoasisquebec.ca/
MCS Special Issue
To view all articles in the Special Issue, Understanding Multiple Chemical Sensitivity (MCS): Interdisciplinary Insights into Science, Policy, and Lived Experience:
Why this evidence matters in the 2026 Québec election
Taken together, the evidence shows that MCS is not a marginal issue. Millions of Canadian adults report MCS, women are disproportionately affected, and environmental barriers can restrict access to healthcare, employment, housing and public life. The evidence also points to practical responses: source control, well-designed fragrance-free policies, accessible accommodation processes, professional education, healthier procurement and building practices, and meaningful inclusion of people with MCS in decisions that affect them.
Download the full PDF: Data and Publications on MCS