
How Amsterdam’s Airport Is Fighting Noise Pollution with Land Art - jath2
https://www.amusingplanet.com/2017/06/how-amsterdams-airport-is-fighting.html
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gumby
There are a lot of opportunities to make functional structures attractive
(even attractions in themselves) but this approach seems to have fallen into
abeyance, in particular in the USA and the UK, for some reasons over the past
50 years.

For example instead of brutalist bollards and jersey barriers, pedestrian ways
could be set aside via grade elevation or attractive, gapped structures that
invite walking instead of looking threatening. Water plants could have "water
temples" again.

It seems like some theory that doing anything beyond the functional minimum is
a waste of the taxpayer's money. But isn't a crude structure also a tax on the
psyche?

~~~
enra
I think in US culture there isn't generally much regard for taste or
aesthetics for some reason. You can see in cities, public places, transport,
offices, people's homes, clothing, packaging. Aesthetics or function is either
not considered at all, or done with a horrible taste (think most airports,
government offices).

In general, at least in Northern Europe, we have beautiful well kept and
functioning cities, libraries and I think it's some kind pride or attitude in
the culture, that while things are necessary, they can be also be beautiful,
it doesn't necessarily have to cost more.

~~~
erikpukinskis
This is so wrong. America is full of beauty, and many have great taste.

Maybe America is not to _your_ taste.

~~~
huntertwo
There is something to be said about beauty being exclusively secondary to a
place’s purpose in the US though. This is evidenced by the fact that when
American cities champion creative efforts, it’s seen as special. For example,
street art in Chicago is seen as something positive but different. All of
America’s buildings aren’t brutalist and ugly, but clearly aren’t looking at
aesthetics as a primary concern.

~~~
paulie_a
I've yet to find any street art in Chicago that is beautiful. This is
obviously subjective, but I just think it looks trashy.

~~~
erikpukinskis
Of the three explanations:

1) you’re in the wrong neighborhoods

2) you have bad taste

3) there is no good street art in Chicago

... I don’t think #3 is the most likely.

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Anechoic
I'd really like to see a technical analysis of this project - I've checked the
usual spots (JASA, INCE Journal, Journal of Sound & Vibration, etc) and
couldn't find anything. Google searches just lead to Paul De Kort's writeup,
and similar articles.

A little background about issues involved: if you have a noise source on (or
just above) the ground, and a receiver on (or just above) the ground with
line-of-sight to one another, there are three paths that noise can take from
the source to the receiver:

1\. The source can emit sound that goes up into the atmosphere, but under
certain atmospheric conditions, that sound can be reflected back down to the
receiver.

2\. The sound travels directly, in straight line, between the source and
receiver.

3\. The source emits sound that travels downward at a shallow angle into the
ground, and is reflected up to the receiver.

For path #3, if the ground is acoustically "hard" (generally meaning non-
porous), the reflected ground path adds to the noise heard at the receiver. If
the sound is acoustically "soft", generally porous, the sound is absorbed [0]
so the reflected sound does not add to the direct sound, and the resulting
total noise is quieter compared to the situation with hard ground. This
explains the reduction in sound level when the land was plowed - the hard
ground (dense, packed soil) was transformed into soft ground (loose, tilled
soil). This also explains why background noise levels drop when snow is on the
ground.

It looks like the Schiphol landscaping addresses mostly #3, possibly #2 (by
blocking direct LOS between the source and receiver). This is interesting, but
the same can also be achieved by a noise wall at the airport taxi and run-up
areas (which is the typical solution), or creating a wide, dense tree belt.
The claim is that spacing the berms by the wavelength of the (presumably
dominant) airport frequency creates greater reduction, but I'd really like to
view technical data to see how well that works.

The articles claims the berms have "reduced noise levels by more than half" \-
is that in terms of sound pressure, sound power, or sound perception?

If sound perception, that's ~10 dB and that's _really_ impressive.

If sound power, that's around 6 dB, which is decent.

If sound pressure, that's 3 dB, which is strictly in the "meh" category.

[0] Technically the sound isn't absorbed, it goes through a phase change so
that the reflected sound cancels out part of the direct sound.

~~~
DoreenMichele
My thinking is this is strongly influenced by the polder landscape. Polders
are how the Dutch reclaimed so much land from areas that should be under
water.

So, it is basically a lake bed that was drained and then stuff built on it.
This means it lacks a lot of the usual natural baffles of irregular ground and
various types of plant growth.

They are basically creating baffles on, apparently, previously essentially
flat terrain with little to no natural baffles.

I'm thinking given that context, it wouldn't take much to make a dramatic
difference.

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jws
Noise power and perceived volume are nonlinear. When the article says: _These
simple ridges have reduced noise levels by more than half._ they are speaking
of power. This means a reduction in perceived noise of about 1/6th. It is
about the minimum change at which a person says "Oh yeah, that's quieter."

Later in the article they mention including more measures from the airlines'
planes and operating procedures to achieve a total of a 10db reduction, which
gets rid of 90% of the energy and people will say "Oh yeah, that's about half
as loud."

~~~
sandworm101
I work with aircraft (big helicopters) and field noise complaints. I find time
of day and weather mean far more than actual noise energy. 7pm, sunset, calm
wind, sunday = noise complaint. We never get complaints at 11am on a windy or
rainy tuesday.

I am very polite on the phone, but if you choose to retire beside an AIRBASE!
Our helicopters have been flying over your house decades before it was ever a
house. Sue your real estate agent for not telling you exactly why zoning
limits your neighbourhood to two-story non-commercial structures.

~~~
dingaling
> but if you choose to retire beside an AIRBASE!

The problem with that position, at least in the UK, is that the social
contract between the airport operator and the local residents was never
revisited.

Most of the UK's airports and airbases date from the 1920s and 30s and are
named after the nearest postal village, which are centuries old.

But a Dragon Rapide or a Bristol Bulldog from that period had a very small
noise profile. When the big-props and the jets arrived the noise levels
increased hugely, but the residents weren't given any concession. Society was
required to adapt to the new noise and pollution levels in the name of
progress.

And now the operators have the audacity to complain about local residents
complaining. If you really want to operate 24/7 in a drone-free environment,
go and build an offshore island airport.

~~~
sandworm101
Our helos are over 55 years old. Not many residents have been here that long.

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namenotrequired
Funny to see this here :) Born and raised right next to what is now
Buitenschot, lived there until 3 years ago. For the last few years, my brother
and I had the unusual habit of going for a run over these ridges and ditches
every Sunday.

There are in fact at least two listening ears, a few hundreds of meters apart,
but they’re not exactly opposite each other so they don’t communicate. Also we
never realized the meaning of that weird pond haha.

AMA

~~~
gpvos
When was Buitenschot built? (I grew up a few 100 m further away, but left
about 30 years ago; I had no idea they had built this there now.)

~~~
namenotrequired
Hi fellow Hoofddorper :)

It’s relatively new, it was built between 2011 and 2013.

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jadbox
Is it just me or has Amsterdam/Netherlands been on Hacker News (and other
outlets) more and more... almost feels like a weekly occurrence now. I've
visited Netherlands last year and was fully impressed with their entire
culture.

~~~
jacquesm
NL is small, densely populated and wealthy. That makes it an ideal testbed for
lots of stuff so you will see a relatively large number of experiments taking
place here some of which are newsworthy.

It's also why we have an enormous offering of car brands and models none of
which are produced domestically. It's a good market to try new stuff in.

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adamnemecek
Speaking of Amsterdam Airport and noise pollution, through the whole airport
there are speakers that repeat the phrase "Mind your step" every 10 seconds of
so.

[https://www.youtube.com/watch?v=0uTySV1Gkh4&t=28s](https://www.youtube.com/watch?v=0uTySV1Gkh4&t=28s)

I've had to spend quite a bit of time at the airport unfortunately (say 6
hours each time) and it felt almost like Chinese water torture. I could hear
it for the next day after leaving the airport.

I find it very hostile.

~~~
jacquesm
These are typically at the exits of the moving walkways to warn people that
they are about to hit terra firma, and face first if they are not paying
attention which is pretty easy given the length of some of them.

~~~
maxxxxx
Hearing "Mind your step" all the time won't help with this. I was at Amsterdam
airport and hearing this hundreds of times drove me crazy while at the same
time wondering what it means. They should put up signs at the end of each
walkway so you get a warning in context. Hearing "Mind your step" while
sitting at the gate doesn't help.

~~~
adamnemecek
Haha yeah even 20 minutes is too much.

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oh5nxo
Article did not spesifically mention air layers, temperature inversion and
downward refracted sound waves. Curved waves in the images imply this
condition, no? Tropospheric propagation in hamspeak.

Changing the color of the landscape might also have a small effect on how the
area heats up on sunlight and so how often unusual sound propagation develops.
silly...

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Mizza
This could have been made into an awesome BMX/skate park. In terms of usage, I
don't know what gets better return for public land.

Next time you're at a park with a skatepark, I bet you'll see it's packed, and
generally there is a totally disused baseball diamond next to it.

~~~
Improvotter
There aren't that many people willing to go to a skate park next to an
airport, it's way too far.

~~~
Mizza
I once flew to China to skate SMP outside of Shanghai. Every year thousands of
people go to Rutland, Ohio for Skatopia. If the airport is accessible by
transit, of course people will go to use it. At least more people than would
go to visit "land art".

Anyway, the point is that you're building it anyway and it looks super
skate/bikeable because it's just a bunch of ridges. Add a few more obstacles
and bam, awesome skatepark.

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Hydraulix989
I wish SJC could do something more about the noise pollution. At every hour of
the day starting at 6 AM sharp (and often at night past the "curfew"), there
are deafeningly loud jets taking off and landing overhead to the point where
it even disrupts indoor conversation. When I lived there in Santa Clara, I had
to wear earplugs to sleep at night, and needless to say, I was out of there
once my lease was up.

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trumped
> The plan is to achieve a noise reduction of up to 10 decibels.

If they can achieve that goal, it sounds very good [1].

1\.
[https://en.wikipedia.org/wiki/Decibel](https://en.wikipedia.org/wiki/Decibel)

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userbinator
Looks like the same design as in a
[https://en.wikipedia.org/wiki/Anechoic_chamber](https://en.wikipedia.org/wiki/Anechoic_chamber)

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amelius
> These simple ridges have reduced noise levels by more than half.

Great, now we can increase air traffic by a factor of two! /s

