Pearson Accountability Alliance

Exhibit E: WHO Night Noise Evidence & Health Impacts

This page summarizes the key findings of the World Health Organization (WHO), Toronto Public Health, and international research on the health impacts of nighttime environmental noise. It is intended as a reference exhibit for elected officials, investigators, journalists, and residents.

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1. How WHO treats night noise and health

The World Health Organization does not consider night noise merely an annoyance. It is treated as a public-health exposure with measurable consequences for cardiovascular, metabolic, and cognitive health.

WHO guidelines explicitly recommend a night noise limit of 40 dBA (L_night) to protect public health, with an interim value of 55 dBA where 40 dBA cannot yet be achieved.

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2. Documented health impacts (Adults)

The strongest evidence for adult health impacts comes from the HYENA Study (Hypertension and Exposure to Noise near Airports) and WHO reviews.

• Hypertension: Statistically significant associations between night-time aircraft noise and high blood pressure.
• Cardiovascular effects: Long-term exposure is linked to increased risks of ischemic heart disease and stroke.
• Stress response: Repeated noise events elevate stress hormones (cortisol) and sympathetic nervous system activity, even during sleep.

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3. Children, Schools, and Generational Impacts

The impact on children is well-documented by two landmark studies: the RANCH Study and the Munich Airport Study.

The RANCH Study (The Lancet, 2005)

This cross-national study (UK, Spain, Netherlands) proved a linear relationship between aircraft noise and cognitive impairment.
Key finding: A 5 dB increase in aircraft noise exposure was associated with a 2-month delay in reading comprehension age in children.

The Munich Airport Study (Evans et al., 1998)

This was a “natural experiment” that studied children before and after the relocation of Munich’s airport. It is the strongest proof of causality.
Key finding: Children near the new airport rapidly developed stress deficits and reading delays. Children near the old airport (where noise stopped) showed recovery. This proved the noise itself was the cause of the harm.

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4. Local validation: Toronto Public Health (2017) & Board of Health

In its 2017 report “How Loud is Too Loud? Health Impacts of Environmental Noise in Toronto”, Toronto Public Health reviewed the updated science and concluded:

• “Newer evidence confirms that health impacts can occur at levels between 42 and 60 dBA outdoors”.
• “The available evidence suggests that environmental noise in Toronto occurs at levels that could be detrimental to health”.
• This contradicts older benchmarks (70 dBA) that were previously thought to be safe.

Embedded for reference: How Loud is Too Loud? Health Impacts of Environmental Noise in Toronto (Toronto Public Health, 2017).

The Toronto Board of Health has since unanimously supported a motion acknowledging environmental noise — including aircraft noise — as a public-health concern and referencing WHO-style health-based thresholds. In other words, local health authorities have accepted the evidence, even if federal aviation regulation has not.

→ Read the full Toronto Public Health Report (Exhibit F)

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5. Thresholds and guidance levels

International guidance on night noise has moved toward protective limits, especially in Europe.

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6. How far behind Canada is

Compared with Europe, Canada is lagging behind in treating aircraft noise — and related pollution — as a serious health issue.

• No Pearson-specific health assessment: There is no dedicated, public, Pearson-focused health risk assessment that applies WHO night-noise thresholds (40 dB L_night) to actual night operations in the way European airports have been studied.
• Noise treated as a planning nuisance, not a biological stressor: Federal and provincial frameworks still largely treat noise as a land-use or annoyance problem, even though WHO, Toronto Public Health, and major cohort studies treat it as a cardiovascular risk factor.
• Nanoparticles and ultrafine particles (UFPs): Around major European airports, researchers and regulators are now studying ultrafine particles from jet exhaust (nanoparticles that penetrate deep into the lungs and bloodstream). In Canada, public reporting has focused mainly on PM_2.5 and NO₂, with little systematic, airport-specific work on UFPs around Pearson that is visible to residents.
• Fragmented responsibility: Health Canada, Transport Canada, Environment and Climate Change Canada (ECCC), the GTAA, and Ontario’s own ministries — including the Ontario Ministry of Health, the Chief Medical Officer of Health, and the Ministry of the Environment, Conservation and Parks (MECP) — each oversee only one part of the issue. Municipalities and regional governments around Pearson (Toronto, Mississauga, Brampton, and the surrounding regions) sit closest to affected residents, but have limited formal tools beyond motions, resolutions, and advocacy. In several cases, councils and boards of health have not replied to formal correspondence or have deferred responsibility upward to other levels of government. As a result, no federal, provincial, regional, or municipal body has assumed ownership of a comprehensive, health-based assessment of aircraft noise and air-pollution exposure for the communities living under the Pearson flight paths.
• Result: Residents are living with noise and pollution levels that international health agencies already consider harmful, while federal systems in Canada continue to rely on outdated metrics and modeling tools (e.g., NEF contours) that were never designed to reflect WHO-style health thresholds.

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7. Source notes & further reading

• WHO Guidelines: WHO Night Noise Guidelines for Europe (2009) and Environmental Noise Guidelines for the European Region (2018).
• Toronto Public Health: How Loud is Too Loud? Health Impacts of Environmental Noise in Toronto (2017).
• HYENA Study: Hypertension and Exposure to Noise near Airports (aircraft noise and hypertension).
• The RANCH Study: Stansfeld et al., The Lancet (2005) – aircraft noise and children’s reading/comprehension.
• Munich Airport Study: Evans et al., Psychological Science (1998) – natural experiment before/after airport relocation.
• Further reading (Spanish): BBC Mundo – “El ruido de los aviones y la salud”.
  Prefer English? Open the article in Chrome/Edge and use “Translate to English”, or any browser translation tool, to read it in English.

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