Data on who is affected, how MCS compares to other conditions, and what the numbers mean for policy and care. Multiple Chemical Sensitivity (MCS) affects more than 1.1 million Canadians — the data tells a consistent story.
Multiple Chemical Sensitivity (MCS) is one of the more common chronic conditions in Canada, yet it remains underrecognized in clinical practice, policy, and the built environment. Understanding its scale is essential to advancing recognition, accommodation, and research.
Note: Provincial figures are approximate, based on CCHS 2020 data. Exact breakdowns available in the full CCHS report. Lime bars indicate key reference values (national and Québec). ▶ Data from the CCHS Report (PDF) ↗
Certain patterns emerge in the data. Women are more frequently diagnosed than men. MCS often co-occurs with other chronic conditions, including fibromyalgia, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and asthma.
People living with Multiple Chemical Sensitivity (MCS) experience substantially higher rates of poor health and greater barriers to accessing health services compared to the general population.
People living with Multiple Chemical Sensitivity (MCS) experience significantly greater financial hardship and food insecurity than the general population. Across Canada, 3.8% have no income at all, and nearly 65% earn less than $40,000 a year — compared to 52% of the general population.
have no income at all — vs. general population
earn less than $40,000/yr vs. 52% of general population
live below the poverty line (<$20K/yr) vs. 26% of general population
earn over $80,000/yr — half the rate of the general population (16%)
more likely to experience severe food insecurity
more likely to be unable to afford balanced meals
lost weight due to insufficient funds for food vs. 13% of general population
Multiple Chemical Sensitivity (MCS) affects quality of life across multiple dimensions. Social participation, community access, and daily activities are all impacted when environments are not accessible.
ASEQ-EHAQ's landmark study tested indoor air quality in 32 Canadian office buildings — half with fragrance-free policies, half without. Buildings with scent-free policies met the recommended TVOC threshold of 500 µg/m³. Buildings without policies did not, with levels reaching 2–3× higher in meeting rooms and offices.
Focus group participants (n=50) were asked to identify their most challenging physical barriers. Cleaning products topped the list at 100% — every participant reported them as a barrier. Multiple selections were permitted.
Among the 17 fragrance-free buildings assessed against CCOHS criteria, implementation scores ranged widely. Scope and communication scored highest, while monitoring, enforcement, and adaptability showed critical gaps.
Across all 17 buildings with a fragrance-free policy, not one scored above zero on adaptability — meaning no building continuously revised its policy based on feedback. Monitoring was in place in only 27% of buildings. A policy that exists on paper but is not monitored or enforced does not constitute accessible accommodation.
When asked what would most improve accessibility, 60% of focus group participants named education as the foundational driver of change — a prerequisite for any effective policy or environmental improvement.
Awareness of what fragrance-free truly means — and that scent is chemical, not cosmetic — is the prerequisite for any policy to work. 67% of occupants in fragrance-free buildings received no training.
Better ventilation, low-VOC materials, and reduced shared air systems directly lower chemical concentrations. Source control — eliminating the product — is more effective than ventilation alone.
Fragrance-free signage without monitoring or enforcement does not create accessible environments. Policies require complaint mechanisms, accountability, and continuous improvement to be effective.
“Everyone deserves the right to know.“
