Noise Pollution

Noise briefing sheet


In a week when the London Mayor, Boris Johnson, warned of ‘dire public health impacts from Runway 3’ and health costs that could spiral to £25 billion, Monika Holdak, research consultant for CHATR, examines the noise impacts of Heathrow’s Third Runway. 


Imagine you have returned home, exhausted, after a busy day, grabbed a quick bite and have gone to bed for an early night only to find that you are experiencing the noise equivalent to a vacuum cleaner in your bedroom being switched on and off approximately every 90 seconds. You lie in bed waiting for the 11 pm cut off, only to find that flights continue until well past midnight. Although their frequency decreases, their noise is accentuated by the absence of other sounds at that time of night. Shortly after you have finally fallen asleep, flights resume again from 4.30 am - if you are unlucky enough to live under the glide path of the daily flight from Hong Kong.

At present, a staggering 725,000 people are affected by the noise of Heathrow’s 490,000 aircraft movements:  28% of all people affected by aircraft noise across Europe. This number is projected to increase to over a million if the 3rd runway is built. These are the people exposed to an average (Lden) daily noise level of 55 decibels or more, which is threshold for noise being considered “annoying” and entitlements to compensation.   

Heathrow has not revealed the new flightpaths that would serve the 3rd Runway, but  several forecasts show that areas of Chiswick that have never been previously overflown would be under a new flightpath. The planes would be at a height of around 2,000 feet, producing noise of up to 70 decibels on a landing approach, which is the equivalent to the noise of a vacuum cleaner a metre away. This is likely to be unrelenting as planes could run every 60-90 seconds or so, up to 12 hours a day with a mere four hour respite, or 16 hours a day for three weeks with then a week's respite. Those areas already under existing flightpaths could lose respite and many parts of Chiswick could experience the noise of two flightpaths simultaneously

Although there are currently regulations in place restricting the number of night-flights permitted between 11 pm and 6 am, London residents frequently report being disturbed by flights sometimes as late as 1 am and starting as early as 4.30. This situation is likely to get exponentially worse given the number of flightpaths that would converge over Chiswick.


You may feel, of course, that you might be able to put up with this stoically and carry on,  but your health, and that of your children, is likely to suffer. Scientific studies show noise annoyance and noise irritation can lead to serious health detriments including hypertension, cardiovascular disease and stroke.

Long term aircraft noise exposure is associated with ‘chronic noise stress’ and this, in turn, is significantly associated with prevalence of high blood pressure. Exactly what you need to keep your heart in tip-top shape.

Aircraft noise also affects child development. The Ranch studies (Road Traffic and Aircraft Noise and children’s Cognition and Health) tested almost 3,000 primary school age children living near Heathrow, Amsterdam and Madrid airports and found negative effects on children’s learning, including their reading, comprehension and recognition memory. A West London Schools Study concluded “High noise exposed children also had higher rates of hyperactivity than those exposed to low noise.” 

Tasks which involve central processing and language comprehension, such as reading, attention, problem solving and memory, appear to be most affected by exposure to aircraft noise. Language based tasks are more affected by noise exposure than non-language based tasks. However noise level is also significantly related to mathematical performance. As noise increases by contour band, performance drops by 0.73 of a mark.   High levels of aircraft noise may impact on everyday activities such as homework, schoolwork and even playing.

A South African study found that “68.7% of people residing near the airport presented with hearing loss, compared to 6.5% of those living further away. Investigation of the influence of high-frequency aircraft noise on the function of the auditory system in school age children confirmed damage to the peripheral cochlear mechanism in the group living close to the airport.” 


There is a real danger of complacency arising from the published projections for average noise levels around Heathrow, after construction of a 3rd runway. Average figures for sound levels simply don’t reflect how noise is perceived by the human ear and brain and, as a consequence, figures such as those in the Airports Commission Report, do not give a true picture of what life will be like if Heathrow is expanded.

For example, it would seem logical to expect that if the number of overflights in a time period increases by 50% (approximately the projected overall increase if a third runway is built), one might expect a sensible metric of noise pollution to increase by 50% as well. Instead, the actual method of calculation results in an increase of only 2decibels in the most commonly-used average. So, if you are a few miles from Heathrow and the current noise level is 57 decibels, a 50% increase in overflights will “only” increase this to 59 decibels! Moreover, that modest increase, in turn, is disguised by assuming that aircraft in the future will be slightly quieter. That decrease will not in reality be anything like sufficient to compensate for the massive increase in flight numbers by several hundred thousand.

CHATR believes that the noise figures used by Heathrow and the Airports Commission are consequently highly misleading.


Transport for London (TfL) has published its research on the noise impact of Heathrow. Their findings closely correlate with CHATR’s own findings.

Using methodology from the World Health Organisation (WHO), which values each lost year of healthy life at £60,000, Tfl’s Chair, Boris Johnson claims the financial impact of increased rates of heart attack, stroke, dementia and other disorders linked to aircraft noise will be “colossal”. Johnson warns expansion at Heathrow would cause “dire public health impacts” and urges the government to “face down vested interests” that support the £18.6bn scheme.

Tfl’s report is also highly critical of the way that the Airports Commission has calculated the population who would be affected by significant levels of noise by 2050 if Heathrow expanded. Currently 766,100 people are affected by an “annoying” level of noise from the airport. The Airports Commission modelled three scenarios and concluded that the number of people suffering such noise would fall. But Tfl points out that this is based on a series of “speculative” future changes to reduce aircraft noise, including steeper landing approaches, landing jets further down the runways and the redrawing of flight paths to avoid homes.

TfL’s analysis indicates that the number of people affected by noise would rise to 986,600. Even under the Airports Commission scenarios, TfL warn that between 98,900 and 277,100 people who do not currently experience significant aircraft noise would do so. “Heathrow has no silver bullet for its noise nightmare,” said Boris Johnson. “You can shift flight routings all you like but you can’t avoid the suffering — you just end up inflicting it on thousands of new people.”  TfL claims that 124 more schools and 42,300 more school children will suffer significant aircraft noise as a result of the proposed expansion at Heathrow.

Last year, the Department for Transport published guidance for putting a financial value on premature deaths caused by medical conditions linked to prolonged exposure to noise. Using World Health Organisation methodology, TfL calculated that the “harm” of a third runway was worth between £20bn and £25bn over 60 years. The biggest cost is related to the health impact of sleep disturbance, which under one scenario is valued at £10.7bn. The dementia cost is estimated at £1.4bn, heart attacks at £400m and strokes at £900m.

If you, your parents and your children are insomniacs, have learnt how to withstand extended periods of sleep deprivation from a former member of the SAS, are unconcerned by your rising blood pressure or your children falling behind at school and are passionate plane spotters with 740,000 to choose from, then there is nothing in this article that is cause for any worry. If you are not, then it would perhaps be wise to consider the options available to head off this impending nightmare for you and your family sooner rather than later.

Monika Holdak joined CHATR at its inception as a research consultant, especially on health related issues. She lives in Chiswick and has recently established a family dental health centre in Richmond.

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