Cost of aircraft noise
June 2016
These notes follow from the Airports Commission’s report, Business Case and Sustainability Assessment – Heathrow Airport Northwest Runway, July 2015.
Our conclusion is that the damaging effect of aircraft noise has been grossly underestimated and that the cost may destroy the business case for the third runway.
The Commission’s report.
Paragraph 3.55 of the Commission’s report provides:
“The noise contours and population estimates in the local assessment have been used to monetise the noise impacts at Heathrow, for inclusion in the economic appraisal. The effect of noise in terms of annoyance, sleep disturbance, acute myocardial infraction (AMI) and hypertension on the Quality Adjusted Life Years (QALYs) of the population living within the noise contours have been considered. These calculations are based on World Health Organization (WHO) Environmental Burden of Disease guidelines and the ERCD report 120930. This approach values the noise impacts by estimating the number of years of life lost or spent with a disability, to get the number of QALYs lost, and uses established values for each QALY lost to arrive at the total monetised noise impact. The quantified and monetised impacts of noise cannot fully reflect people’s individual experience of noise. Some of the qualitative impacts are discussed in the Noise section, and the Quality of Life assessment also includes noise impacts on peoples’ wellbeing”.
And at Para 3.56 “The noise impacts with Heathrow Airport Northwest Runway in the Commission’s assessment of need carbon-traded demand scenario is £1 billion (PV, 2014 prices). This figure does not take into account the Commission’s recommendation to end scheduled flights in the core night period between 23:30 and 06:00”.
We comment; the £1bn represents the loss from the 60 year evaluation period. It equates to less than £100 per flight, or to fractions of a penny per person per disturbance. All those values seem entirely trivial.
In any case, the use of “QALYs” is at variance with transport studies where time saved or lost is the metric, a metric which can be criticised since time on a train or when travelling generally is not lost in the pure sense. Instead such time may be used and enjoyed, e.g. working, reading, resting or simply enjoying the passage. In contrast, noise from an aircraft may completely destroy the effective use or enjoyment of time.
In the following we make estimates of the financial loss to those on the ground using a time loss approach. In principle we multiply the Air Traffic Movements (ATMs) by a disturbance time, the value of time and by the number of people disturbed. That provides an annual cost which may be summed and discounted in the usual way to represent the Present Value of the lost time for comparison with the scheme’s benefits. The price and discount base is 2014.
Paragraph 2.9 of the Commission’s Report says that there are currently circa 470,000 Air Traffic Movements pa at Heathrow, close to capacity. Para 2.19 provides a limit with expansion of 740,000 ATMs – presumably as a result of the new runway. The implication is that the runway enables an additional 270,000 ATMs. We will use 250,000 in calculations. If those are spread over the year and over 16 hours a day we have roughly one ATM every 1.5 minutes. That may represent a minimum disturbance duration due to overlap. A maximum may be 5 minutes, allowing two for the over-flight and three to refocus, but only if there were fewer ATMs.
The HACAN clear skies blog provides the following:
“The numbers under the Heathrow flight paths are well-known: currently over 725,000; a third runway would add around another 150,000. What is much less clear is how many of these people are, or will be, deeply disturbed by aircraft noise”
“However, there is some research to help us find that answer. It is estimated that about one in ten people are particularly noise-sensitive. According to the German psychologist, Rainer Guski, these people are likely to become more annoyed by noise than the general population”.
Hence a starting point for calculations is a population of 150,000.
In calculations, available here, we use the DfT WEBTAG discount rates of 3.5% for the first 30 years from the base year (2014) and 3% thereafter, a value of time consistent with “other” non-working time, at £6.81 per hour for 2014, and a growth factor of 2.1% pa; all consistent with the DfT’s WEBTAG data book. We set the opening year to 2026, as reported.
On that basis the discounted value of disturbing 150,000 people for 1.5 minutes for 250,000 ATMs pa for 60 years amounts to £270 billion, vastly more than the £1 billion provided by the Commission.
If each ATM affects only one third of the people in the noise envelope at any time (due to varying flight paths etc) then the loss on the ground falls by a factor of three to £90 billion.
If, at one extreme, there are those who lose no focus at all and at the other there are those who lose the full 1.5 minutes, according to noise sensitivity, then, instead of a £270 billion, or £90 billion loss we should halve those values to £135 billion and £45 billion. If the £45 billion is the more realistic number it may then be halved, on the basis that the use and enjoyment of time is never completely destroyed. Even then the value lost, £22.5 billion, would be overwhelming. It would reduce the net present values in the Commission’s report table 3.23 (ranging from £1.4 billion to £11.8 billion) to heavily negative numbers, namely, and after adding back the study estimates of the impact of noise, to the range minus £19.6 billion to minus £9.7 billion.
Possible criticisms of the above include (a) properties may be insulated, so mitigating the effect, to which we rejoin, windows may then never be opened (b) people may adjust, to which we rejoin – some will, some will not; in any case, at what cost.
Conclude
The value of time lost on the ground, due to aircraft noise, may be very much greater than the net present values estimated by the Commission’s economic analysis. The effect may be to destroy the business case for the third runway.
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