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[Music]
okay our next
talk is numerical air quality modeling
systems uh our two speakers will explain
to us how scientific methods can be used
to model the quality of of um pollution
or air quality in general uh our
speakers are Martin Raa uh he is with
the Hol Centum for hon and his main
research subject is the um exposure of
pollution
concentrations and um on his um on his
left there is johanes beer main research
interest is the meta transport of in the
ecosystem um and he's with the hams
Institute as well please welcome them
both with a huge round of
[Applause]
applause check check ah okay hi everyone
we are johanes Biza and auto Po and
today we will take you on a journey um
on numerical air quality modeling
systems from emission to exposure
actually we realized that it's more like
a roller coaster ride because there are
so many topics that we have to cover
that um we need to be really quick and
will be bumpy but the idea is that after
our presentation you have a
general understanding of what we are
doing why this is important uh what are
state-of-the-art Concepts and
applications and what it can bring for
the future so let's dive into it and we
will cover all of these topics we will
talk about air pollution where it comes
from why is it important measurements
then of course the numer iCal air
quality modeling systems applications
exposure we have a little finale and
then you can ask us anything if there's
still time
left so we dive right into the first
topic which is air pollution and we will
start with a little lesson in history so
this is a picture of the great smok of
London in
1952 and as you can see you can't see
[ __ ] it's very foggy so uh this is
basically the smoke that happened and it
happened because um it was Winter it was
cold there was not much wind and on top
of it literally there was a warm layer
of air so if you have a warm layer of
air on top of a cold layer of air you
have something we call inversion in
Metrology and that means basically that
all the emissions are trapped below this
warm layer of air so we have all these
pollutants trapped inside and what
happened here was that there was lot
lots of coal burning so people burn coal
to eat their houses and for industry and
this resulted in
Smoke um as a result of this smck many
people died so um there are some
estimates from 20 2009 from the UK Met
Office that correlated the the smoke
that happened to uh the death that
occurred during these days which you can
see here on the left and the actual
numbers are estimates of 10 to 12,000
people that died due to smoke and many
more got sick but the big question here
of course is what is smoke because smoke
can be a lot that looks like smoke or
fog um and in this particular case we
are talking about winter smoke which I
said it already due to the burning of
coal there were a lot of emissions and
in particular these were emissions of
sulfur dioxide so you see here so SO2
sulfur dioxide keep that in mind because
we will have all these little um
pictures of the the pollutants we will
have them reappearing in the
presentation often so there was sufur
dioxide and there was parate meta but
that was not everything because both of
these are in high concentrations already
toxic but what happened here was that
also the air was saturated with water so
we had a lot of high humidity and a lot
of sulfur dioxide and in combination
this leads to the formation of sulfuric
acid and as the term acid says already
it's acidic so it's you shouldn't
breathe it it's just it's dangerous for
your health um another thing that
happened during the 1950s were
situations like this uh in Los Angeles
so you had this um also smoke again but
that's a different kind of smoke because
this happens when there's a lot of
sunlight when you have cars and Industry
and also trees all of these they
emitting lots of substances and in
combination with sun again you have the
formation of smoke and if you breathe it
it's dangerous for your health actually
it's so dangerous that you are gathering
with your friends and basement wearing
gas masks and asking yourself what is
this smoke and as I said it already in
this case it's summer smoke so sosm is
basically a product of nitrogen dioxide
which is mainly happening due to
combustion in cars but also in industry
and other combustion sources uh plus
volatile organic compounds which is
actually a huge range of compounds which
um Biza will introduce to to you later
and under the influence of sunlight you
have the formation of ozone and ozone in
high concentration is toxic and can
endanger your health so as a result of
these events and many other events
around the globe there have been some
clean air acts so-called and the first
one was in 1956 that was a direct
consequence of the smoke in London and
it was a milestone in legislator air
quality regulation or regulation of such
things in general um and some of these
measures like regulation of fuels and
smoke free zones are still measur
measures that we are applying today to
regulate air
pollution um in
1970 there was the uh Us Clean Air Act
and at the same time there was also the
establishment of United States
Environmental Protection Agency that's
not a
coincidence and today uh the the EPA
does a lot of other things and not just
regulating air quality so very two
important acts that happened in history
with respect to air
pollution so when I talk about
regulating air pollution we are we can
come from two different perspectives
here uh we have for example the the
guideline values which are international
guideline values these are concentration
limits or values that you should not
exceed because they endanger your health
and this is based on many studies that
were gathered by the wh it was last
updated a couple of years ago and is
actually um yeah it's it's a guideline
value so we shouldn't exceed these
values then there are limit values for
example the limit values which are
established in the European Union by
European commission they oriented they
are orienting them
um along with the wh values but as you
can see they were last updated in 2008
currently they are under revision but
the existing limit values we have right
now are way higher compared to the ones
we have from the wh nevertheless these
limit and guideline values are success
story because if you look for example
what's happening in the European Union
with the population in urban areas for
so SO2 you can see that less than 1% of
the population living in urban areas is
exposed to values of so SO2 considered
to be dangerous for your health today or
in
2021 but for other pollutants you can
see a clear difference between uh what's
what's going on because you have here
particles in different sizes you have
ozone and you have NO2 and if you apply
the limit values by the EU they are
still a problem for particles and ozone
but if you apply the guideline values by
who it looks like we have a problem
almost everywhere and this is just this
thing that the European commission
values are not updated for a long time
they are envisioned right now and they
will follow probably the wh values but
they will probably not be as strict as
the wh
values although if this is a success
story um if we look in other regions in
the world like where there's no such um
regulation for example here in
Kazakhstan you can see very well we have
winter we have smoke and this is what I
what talked about before this is the
so-called inversion so the clear sky
above is warmer there's warm air masses
below we have cold air masses
everything's trapped inside so it's you
don't want to be there same thing in
China sometimes smok occurs so there are
many regions in the world where this is
still a big problem but not only in
other regions coming back to London we
also um had something very unique again
in London there was a ruling um that a
9-year-old girl from from lsam in South
London she died in 2013 as a direct
result of air pollution and this ruling
stated that air pollution made a
material contribution to her death so
there was the first ruling of that kind
ever and I think this introduces the new
yeah new way of dealing um with air
pollution if we go back from the
individual to the global perspective
today air pollution is considered to be
one of the world's largest environmental
health threats accounting for 7 million
deaths around the world every year by
The
Who and 4.6
attributable to uh ambient air pollution
so I I guess we we can settle that we
have a big problem here that we should
start to tackle and actually there's a
lot of work to
do thank you um and um the thing is most
of the time the idea is you can only
manage what you can measure so we need
measurements how are these measurements
done for regulatory uh purposes so there
are these regulatory measurement
networks and what you can see here is um
an example of such a classic air
monitoring station that is useful such
purposes is an Essence and measuring the
urban background it this um containers
they look more or less the same
everywhere probably you if you're from
Hamburg you have seen some of them they
look similar it's always a container and
there's a lot of equipment inside which
is standard equipment it's calibrated
and maintained and these equipments cost
more than €100,000 so it's very
expensive to do that but they measure
more than 20 pollutants continuously so
it's quite good to have these to get an
idea of what's the air quality situation
like for example in Europe here you see
the network the European air quality
monitoring Network by the European
environment agency and these are results
for p
2.5 um the dots are measurement stations
measuring in annual mean which is
displayed here and on the first side it
looks like um we have a good spatial
coverage so we get an idea of what's
going on here but imagine each of these
points is one station and the size with
respect to the scale of the map you can
get an idea okay there's lots of space
in between so if you zoom in you see all
of these Mees stations are far away
sometimes they are even that far away
that the data comes from Brandenburg and
is instead of searching for Internet
searching for for air quality uh
measurements but can't find them um so
what I want to say here is the coverage
of measurements is sometimes really
sparse so we need more measurements to
fill all these gaps for example um I
will skip this
one so what can help here is for example
do it yourself and locost S on networks
and I'm pretty sure or I hope that some
of you in this room are dealing with
this topic because I would like to get
in touch with you uh there's many
different networks I just named some of
them sensor Community former Lu daten
info um lu D at open cologne and so on
and we did a little study for
Hamburg where we wanted to evaluate um
some modeling we did which I will also
show later but just to get an idea of
the spatial coverage in Hamburg you see
here all these dots are measurement
stations where these um these
measurement pipes are located and they
are giving us um yeah values into a
database of
pm2.5 so it's it's really useful to use
this to get um the spatial distribution
of the pollutant concentrations in a
city like Hamburg better so it's it's
really an update compared to the 16
measurement stations we have um
officially here in Hamburg what's kind
of a problem is um the quality of the
sensors but there's lots of stuff going
on to to improve the quality with some
algorithms and what is also sometimes a
problem is the temporal coverage so not
all of these sensors are really
recording the entire year but some of
them have some some data gaps that we
need to fill them but anyway it's very
useful to have these
measurements um coming back to the
global scale we have here a screenshot
of the world air quality index project
and actually they are gathering all of
the measurements available I think this
is the most comprehensive database um I
know which is accessible all the time
online and you if you zoom in you see
all the lowcost sensors you see the
official monitoring sites you see
everything so it's very nice but what
you can also see on the first side is
that we have a global North bias so us
covered B China India that's all fine
and Japan and Europe and Australia there
are also some measurement stations but
like South America and Africa okay
Siberia too but uh we have some some
gaps here which should be filled
um yeah so coming to an end for
measurements or
observations they are still the gold
standard uh when we talk about high-end
instruments the problem is just that
they are very
expensive um because of Technology
calibration operation maintenance but
they are highly reliable and
compatible problems or things that we
could improve are the limited spatial
and temporal coverage so as I said
there's a global North bias especially
and then for the high-end instruments uh
here do it-yourself sensors can work the
problem is also that we can only measure
what happened and what happens so we
can't predict the future with measur
ments not yet not that I know and we
also have very limited source source
abortion
capabilities which is also um a problem
is that these measurements they have
detection limits so if you have very low
concentrations it's hard to measure it
and also we have errors which are
connected with measurements and these
can deviate from the True Values and
with this I would like
to welcome you to the model
welcome to the
model you made it here I'm amazed after
Martin told you that we have a problem
and that we can measure it I mean you
probably think what what benefit if I
find out if my food is poisoned after I
eat it so wouldn't it be nice to know
beforehand I mean wouldn't it be nice to
know how air pollution is tomorrow or
next year or to know what some policy
decision or some regulation would
actually do once we enact it and huh
lucky we can do models there's just one
problem I mean with the models is that
they're basically all wrong um but
sometimes luckily they're still
useful and then that's the point where
you would start defining what a model is
and that's difficult because basically
anything is a model um
really anything can be a model so now
let's find out which model we actually
want to use to answer our question at
hand and our question is that we want a
model that has everything from the
emission to the exposure so we need
stuff being emitted into the atmosphere
we want things flying through the
atmosphere and move we want them to
react and change become more toxic less
toxic
and then at some point we want to know
is the stuff actually going inside a
human and okay that's our goal so as a
modeler of course we think in the
Box um not outside the box today we're
in the box and so we imagine a box where
we have these processes we have stuff
coming in we have chemical reactions and
we have transport and yeah maybe more
boxes is nice so we start fing the
planet with boxes and our atmosphere is
basically just a huge bunch of boxes of
different sizes and here just let me
deviate a bit on the topic of scale
because it it really depends what do we
want to look at if we want to know like
the global circulation how much
pollutants come over the Atlantic from
the US to Europe you can use crit cells
that have a size of hundreds of
kilometers that works fine um um if you
want to know something about air
pollution in a city you really need to
go to the sub kilometer scale where
you're 10 100 m basically you can see
that on this fancy diagram that shows
you on the
x-axis actual scales distances on the
planet and on the y- AIS you see the
characteristic time scales of different
physical processes and so they basically
see we're between a few meters to a few
hundred kilometers in our crit cells so
let's just say we filled a whole planet
with crit cells and now we want to start
modeling and an air quality modeling
system is is a modeling system because
it's basically just a bunch of different
models getting thrown in a box and
connected to each other and here we
start with the transport so we don't
think transporting so that's in our case
I we call it the hydrodynamic model it
could be an ocean model if you would be
interested in pollution in the ocean but
in our case of course it's an
atmospheric model and there was a really
nice talk on the last chaos Congress so
if you're interested in um climate and
meterological modeling there you can now
if you watch Us online go hop over and
come back um it's just these models
we're using them and we're building upon
them and there's just no time to speak
more about them but in the end it's just
the physics it's the temperature it's
the pressure it's the movement the wind
it's it's the water like the rain and
the water vapor going around and um now
here that that's very are in in 2023 so
you see on the on the left side the
original Apollo picture from the 70s and
on the right side a a recent 1 kilom
resolution Global atmosphere ocean run
with the ion model that's actually the
model that's used for the German by the
German Weather Service for the forecast
so you have seen that and we're really
at a point where personally it starts
being difficult deciding which one is
the
picture and um with that I can take some
breath get the first mesmerizing video
with the supplemental information into
you and so basically we now have things
moving through the
atmosphere check first model is there so
now we want to have stuff coming in so
we need doing emission modeling and EM
Mission modeling is just a nicer way of
being an accountant of everything
because it's everything emits nature
emits plants emits even the planet
itself G geogenic volcanoes emit U of
course I mean the humans are the big
emitters with Mobility energy industry
and agriculture we quite a deal but all
those natural sources a forest might be
nice but in a certain circumstance it
can be an emission source of some
pollutant and then it's not only the
pollutant U this the pollutants
themselves but it's also precursors you
you're not just modeling something it
goes in the air transports really you
need to reproduce at least some basic
atmospheric chemistry which means you
end up with something in the range of a
few tens dozens of species of substances
to really being able to do that and here
are the friends again we keep showing
them so we secretly give you some
chemistry lessons Without You
noticing um those pesky blue things down
there it's
basically hundreds of thousands of
different carbon chains so we try to
somehow not have hundreds of thousands
of difference so we use some estimates
and um
but that that's very high level so how
do we actually do it and there we
basically have have the two general
approaches it's coming from the top down
or from the bottom up and basically it's
a top down approach is when you have
some fancy statistics like imagine you
know exactly how much gasoline was sold
in Germany in the last year you know
exactly how much cars have been sold or
are registered and just from those
numbers you can estimate like how much
nitrogen oxide how much carbon monoxide
did cars emit in Germany then you have
this
number and then you start Distributing
this number into every crit cell into
every time step typically emissions you
look at like hourly
values and then at some point from this
one estimated value you come down to to
actually a map looks a bit like that um
you use some GE reference data
population data socioeconomic data sets
unemployment statistics there's more
pics in SCH hin than humans I found out
um yes really it's true and um and then
you just use Bunches of profiles and
different Tempo distributions to
basically get your big total number into
each and every of your little crit Sals
um the opposite way is that you have no
idea about how much is emitted but you
have a pretty good idea about the
sources and then you just come from each
source and estimate each source and
here's an example for that that's the uh
shipping anti-collision AIS system so
you get a global coverage like every
five minutes of every major ship with
the exception of those Russian black
Fleet oil tankers that turn it off and
then you actually can get it the data
for every oil tanker in the world how
big is it how heavy is it what engine
does it have when was it last rehauled
what what kind of fuel does it use and
you basically model every single ship
and
then equally you end up with an Miss
Mission map I tend to forget
breathing you need a
break okay
um Stay With
Me um let me just give you a little
example that's just a what popped up
when uh it it's basically just an
emission map for vehicle emissions in
Germany for different Road types and the
total emission there's the same amount
of stuff emitted in Germany but you you
can also see that they look similar but
definitely different you can see fancy
artifacts and some strange things in the
top down which shows you that you
Interpol
um and you can see much more detail in
this this detailed model down there
where basically there have been cars and
destinations and people driving on
actual roads and
um yeah that's maybe the first first
time to complain um so you you model
these cars and then of course one thing
is you have an emission Factor so like
look here2 G of NO2 per
kilometer and I mean for a few years all
the modelers knew that we have to
multiply our uh vehicle emissions with
some Factor at least two or three and
then no one was really surprised when it
came out that the emission factors
weren't right because actually models do
work you wouldn't believe it I mean they
say everyone believes the measurement
besides the person who did it No One
Believes the model besides the model and
um yeah trust me
and having now this this monster of an
emission model with all these sources
and species we cannot only have things
transported we actually can have stuff
transported that's from our colleagues
in K the kit and you can see some
Saharan dust that's blown up and here
you can see a nice episode actually the
Saharan dust then is transported up to
us um but it's still not enough remember
we wanted also things to happen so we
want chemistry and all our our species
and pollutants to react with each
other and
um I mean it's mostly nitrogen and
oxygen what what people aren't aware is
like how how few of those air pollution
molecules there actually are we're
talking about a few per million of air
molecules with some toxic substances it
goes even to
billions and so what do we do Martin
said I couldn't do a complete
atmospheric chemistry lecture no one
would like it and we don't get two hours
additionally so um we compromised on two
really interesting examples and I try to
be quick and easily to follow and we
start with tropospheric ozone so you
think also and that's nice we have it in
the stratosphere it takes out the UV but
we also the tropospheric ozone that's
down here where we live and breath and
it's a completely different mechanism
there's basically that's a simplified
thing that tries to convey the message
that you have two circles that interact
so you have this n O2 circles and you
have the big circle in the middle and
here you can just follow like this
little little VC how it's getting into
the circle and then it interacts and now
on the bottom you see oh the first time
the circle went through so we have
produced some ozone and the VC happily
continues it hits the other cycle again
and in in this way the idea behind that
is that it's a highly nonlinear process
break one Circle the other doesn't
matter so one industry in one location
could be a huge problem for oone take
the same thing somewhere else it doesn't
matter
because um if you don't have one doesn't
matter if you add the other and then I
stumbled uh randomly about this picture
on the internet and I thought I mean
it's nice I like trees but poas are
actually one of the highest eocs so I
don't really see a nice tree I see like
a deadly chemical trap no wait wait wait
wait a minute wait a minute boring sight
is coming in because actually we did
some modeling studies on that and uh it
really depends on where you are and when
are there for example in Hamburg and in
the rhin ru area the impact of plants on
formating extra ozone is really low like
2% in Berlin during a heat wave there
was an impact of up to 12% and sometimes
even higher but if you look at the
general findings based on literature you
you can see that it's really important
what kind of tree you have on the left
you have a tree that emits just a few
voc's and on the right a lot of voccs
and then it also depends on the
conditions you have so if there are
already a lot of voc's uh compared to
nox
um it's it's really important how much
there is so if there are a m a lot of
these high VCS and there are a lot of
these trees that emit a lot of VCS there
will be oone formation so just to jump
in here yeah yeah we still have
chemistry to do yeah so um sorry for him
interrupting um because now that that's
the that's really interesting it's
secondary particle formation so isn't it
thrilling just the word and um basically
what you have is that something is
emitted as a gas sticks around in the
atmosphere and once it meets another gas
from a completely different Source they
can actually build particles and that's
the example here with the ammonia on the
one hand and the sulfur and nitrogen
dioxides on the other these are gases
that get emitted let's say there's a
ship emitting NO2 there's a cow emitting
NH3 and the stuff oxidizes and it
basically turns into mini magnets and
then it starts being transported with
the atmosphere and when they actually
meet the mini magnets will engage and
you form
particles and um that's really
interesting and I'll show you a nice
video in a second to show how
interesting it is but um with all the
talk I think I managed to get through
three of our four models so we have
transport we have like a metrological
model the physics and all the transport
we have an emission model that gives us
all the stuff getting into atmosphere
and then we have the things reacting in
the atmosphere so I guess we can start
with some interesting applications that
we did like
randomly we have this video um and again
that shows how nice models are so here
basically you run the model with
everything and then you add a source or
remove a source and by looking looking
at the differences between your runs
here we have the secondary particles
formed from ship emissions so it's only
the emissions from ships and so in the
English Channel you will have all the
NO2 going into the atmosphere and when
the wind gets it over the the coast line
it reacts with the ammonia and then you
can get these nice blobs and that's a
specialty of the pm2.5 because it's so
small it's it's not heavy enough doesn't
fall down
so these blobs basically persist until
they hit a rain and if it doesn't rain
it will just stay there
and oh a 7
microgram blob just bent over Hamburg
that's already like half the limit value
that also shows you that on a given day
a source far May might ruin your air
quality nothing you can do and another
thing with these particles is that
especially with all those diesel
Vehicles a discussion was really
strongly about there's the particles
there's too much NO2 coming from the
vehicles and then with a a student Anna
a few years ago we thought yeah but what
about if we removed the ammonia instead
of the NO2 and basically you just see on
the left side a map for Europe with the
secondary particles in our standard
prediction what it should be and then we
we didn't even make people vegetarians
we some World Health Organization diet
with reduced food consumption and meat
consumption and yeah just having less
manure and animal husbandry some areas
really have the particles already that
was quite interesting we have some
examples Yes actually I would like to
catch up on what you introduced um about
the advantages of modeling because uh as
as you said there is the chance that we
can do Source portion man and we did a
little study here for hurg in 2012 and
you can see the total PM 2.5
concentration on the left and on the
first side you see some hotpots there
but the question is now where is it
coming from so what are the responsible
emission sources and on the right you
see industry Residential Heating ships
and traffing with all their relative
contribution to that and this is
something you can easily do with
models um in this case you can see that
for traffic for example we have a big
problem like everywhere then when it
comes to ships and Industry it focuses
on specific reasons and this maybe you
keep that in mind for a
while um and what we also can do with
models as you introduced uh we can do
future scenarios so uh I know 2020 isn't
the future anymore but at that point
where we did this study that was in 2018
it was published then in
2020 so um this was still the future and
we made some prognosis with scenarios
what happens in 2020 and modeled it and
then if you do the difference of these
you can see what's what's the impact
where is the biggest impact what are the
sources where we can really start to to
regulate and you see again it's
traffic so then um there have been some
traffic bands in Hamburg maybe some of
you know maybe some of you can't
remember and I um yeah these are two
streets here in Hamburg where have been
banned for diesel trucks and banned for
diesel cars and if you exclude some
specific trucks or cars from these roads
to red use the measured concentration
then it might appear that you don't have
a problem anymore but if you would have
run a model you would have seen that the
air pollution would just have shifted to
other regions so it's really a question
how useful are such such meurs in the
entire perspective of a city okay still
alive okay good
um
and yeah we can clearly identify such
such such things with models it doesn't
um
Narrows down the effect that happened
there of course the concentration went
down
um what's going on
M yes okay um coming to an actual idea
for scenario we can model we do often
and we like to do some Maximum Impact
scenarios for example here what would
happen if he would introduce only
electric cars um in the inner city of
Hamburg and and also we fire them with
coal so the dirtiest source of energy we
know right now but still what would
happen if we would do it and you could
see that even if we in the year 2020
would have exchanged all the cars in the
inner city by electric cars there would
have been substantial reductions of NO2
up to minus 20 microgram per cubic meter
and actually that's the uh existing
limit value right now so this would have
a really nice impact and the higher
emissions from power plants at that
point there was still the the power
plant and more Borg active right now
it's not anymore but like the impact of
additional energy to power all these
cars was very small so we are talking
here about ranges of 0 to 2 microG per
cubic meter so also very nice model
application and what we did in the last
year
we um created an urban air quality
forast for the city of Hamburg so up
there is the URL you can all look it up
on your iPhone it's public and it's
based on all the measurements uh all the
models you
introduced um so it's really based on
science we are doing on a daily basis
and it's improved all the time but it's
still very ugly so if some some of you
here might help us with making it a bit
nicer I would happy would be happy to
talk to you after the talk yeah who
thinks that scientists make beautiful
products I don't get it no and we're
also not good talking to people anyway
um okay so I think we now have the full
chain of modeling system the air quality
numeric modeling system almost because
we still have to talk about the exposure
so what is
exposure um basically that's the amount
of air pollutant concentrations that you
are breathing so we are here in the
middle we have now our air quality
modeling system and now we want to know
what are the health effects and there's
a step in between that's the exposure
and I really love this topic because
it's sometimes it's so simple and then
also so there's so many impacts um so
what we actually do is shown here on the
left and it involves some things that
are not happening at home so we are not
at home all the time we go out we are at
the communication Congress we are on our
bikes we are doing whatever inside
outside different locations but the
problems with the established exposure
assessments is that they think we're
doing this so they basically assume that
we are living on our roofs or at our
Windows all the time every day every
hour of our lives and based on this
assumption health effects coming from
Air pollutants are calculated and I'm
pretty sure that each of you now
understood already that there's probably
a big uncertainty and bias in it because
that's simply just not true but of
course there are scientific methods to
tackle this problem and um on the left
you can see again this this distinction
between a static individual staying at
home all the time but the concentration
changes every hour and on the right you
have this mobile individual that moves
through the city so we can identify all
these areas in the city and the
concentrations but it really doesn't
help if we get if we don't get the
population activity right so where are
you and when and there are of course
measurements you can use you can use
mobile phone data agent based modeling
but there's also something called the
time micro environment activity approach
it sounds
really aggressive I would say because
it's whatever um but it's it's easy it's
simple and it's nice I really like to
use it so the idea behind that is you
classify uniform areas in a city you say
these are work environments these are
home environments these are transport
environments and then you can go and say
okay where are these environments then
you use satellite products for example
the Copernicus Urban Atlas you have
satellite images they are produced then
to land use data and then you can just
cluster them and map your environments
so you really know where are all these
environments in any region you can
imagine in Europe and there are also
some other projects for um other
countries in the world of course what
you then do is you do some temporal
mapping so it's basically a bit like a
mission modeling but with the population
so you know a certain fraction of the
population is at work right now at a
specific uh time during the day so or in
traffic or at home or wherever and you
can also focus it on specific spefic
groups of population and so on so you
just combine this information and on top
you also have the chance to take into
account the infiltration of the
concentrations that are outside to
indoor environments based on these
clusters you define so you have
measurements that tell you only 90% is
coming in and you can take this value
and combine it and then you combine all
of this and you get a dynamic population
instead of assuming that we are at home
all the time we now have some
Dynamics and if we compare this now with
is the static assumption that we are at
home all the time um we did again for
Hamburg because we just love Hamburg and
we are close to Hamburg so we just do
everything we do for Hamburg as a test
case um you see here in green
residential areas these are areas in
Hamburg where people live and in red
these are areas where not that many
people live depends on what data you
using um the green shows now um um
reduction so that means we moved the
people away from the green areas to the
red areas and all these red areas have
not been considered before and if you
remember I showed you the sourcer
portion M before like these areas are
the highly polluted areas in hurg so
there's industry and there's shipping so
it's really important to take into
account that people are working there
that they are in transport and so on so
we can imagine that this will have an
impact on the overall exposure and
actually we did many many studies in
Europe in different cities to identify
what's the signal here what's the bias
what are we under estimating and it's
really a significant signal in many
urban areas so we have up to 1% higher
NO2 21% higher
pm2.5 and more recently we did a study
to tackle this Dynamic problem for all
um the European 27 countries and we also
saw a signal there that it will be
underestimated and if you now think
about that um the EA the European
environment agency calculates the
exposure and based on that the health
effects and that they say each year
600,000 people die earlier so premature
death because of um air pollution and
you add these five and
3% probably the health effects are worse
than we when than we know right now so I
think it's really important but also
very easy to take this into
account and there was a great um I
should call it great but for a scientist
was kind of great this pandemic
situation because um was a real real
world experiment so there was a lot of
data collected during it and we had some
kind of a Baseline and and the
difference so we now know because Google
and apple they collected a lot of data
and we use this data to to identify
what's the impact of changing activities
on emissions and air quality and then
eventually exposure so people were less
at uh work more at home there were less
in transport this all has effects on
emissions and many many studies
identified that the concentrations went
down but there were just very few
studies that also took look at the
exposure so how many were we exposed to
how much were we exposed to and we did
this and of course when you are not
assuming that people are still at the
same locations as they were before the
pandemic the exposure goes even lower so
we are happy that this kind of data
exists and that we can use it and we are
pretty sure that there will be more of
these nice data sets that we can use to
improve our emissions that we can use to
improve our exposure and so on and with
that um we we have to come slowly to an
end and this your part my mic working oh
yeah um we're slowly approaching our
destination the cryostatic sleeping
Chambers will be deactivated soon um you
might have noticed we really would have
liked to keep talking and we can lock
the do so there's no way out but
um the thing is I guess we could give
you an overview of what the thing is
this air and this pollution and what
kind of models we use so for last but
not least it's where are we doing that
actually and um so you can run these
models on a workstation so I mean I know
phds that got a workstation and can do
simulations there but we're
approaching a point where really you
need especially if you want longer time
scales you want to do scenarios and go
now higher resol utions a global
coverage like to call it gloal because
there used to be this modeling community
on the high solution scale and This
Global people and with the computational
capacities capabilities it's really uh
basically becoming one where we can
model globally with high resolutions and
um it's actually one thing that's a bit
special about all this this um climate
and chemistry modeling is that it's huge
we we can have a domain with a million
crit cells and then we have tens
hundreds of variables and um it just
means we have crazy uh requirements
concerning the data
um
so we can in theory calculate our stuff
on any HPC machine but uh that's a
really nice thing that um here in
Hamburg we have uh comes on the next
slide we have the the lant system yeah
let me go there um that's that's a super
computer in Hamburg it's a German
climate Computing system where our
Institute is one of the shareholders and
I just checked we 74 on the top 500 list
but um it's as I said not about the the
computational power it's really about
the the space so you
easily fill like 30 50 terabyte with a
year worth of data and then you might
have 10 or 50 and so it gets really huge
and uh our system is actually slowly
approaching the exabyte I'm always
waiting when I get prompt with like an
EB because the PB is still confusing me
and I don't know but that's something I
just want to mention why is there no
16bit floating point in in data formats
like net CDF I I get the suspicion that
half of the dis space is just filled
with insignificant
digit um but then no one wants to
interpolate on some integer uh value and
have an an a scaling factor or stuff
like that um but yeah that's what we're
doing we're calculating uh and using up
space and energy and hope that we
produce less air pollution than we uh
prevent with our work and um
that's
that's he could model that no yeah we
should be there in 10 years though um
yeah with that just so I hope what you
got away is that there's a quite
interesting
multi-disciplinary topic that covers all
kinds of natural science and computer
science but also has strong links to
social science and policy making and um
that is actually relevant and although
people aren't that afraid of briefing
the air like for example some people
flying it's it's what probably will kill
you and um what's now happening is that
I mean we're just wondering that there
was no talk about this subject at all we
thought there something on climate
models but these air pollution models
that there has been really a development
over the last 20 years that these things
are now really getting to a point where
you will probably are already starting
to be confronted with that and I mean
may it be that you're an allergic person
and you get your Poland forecast or um
that maybe you benefit that an urban
development planning project was based
on on a Model study um I'm just very
positive that these things that are now
moving towards Earth system models we
don't only have the atmosphere but we
have the ocean we have ecosystems uh we
have even a model where we have like
fish and um so actually we were coming
to a point where we have like a digital
twin of the complete Earth system where
we can track pollutants where they going
where they coming from and can I go
outside of my house tomorrow
with that thanks for sticking with us
um yeah there are any question well we
we have a big problem um I think we
didn't mention it yeah we are we are no
computer scientists so we apply all of
these models on supercomputers but uh
sometimes it's hard and uh yeah we can
we we need people like you to support us
and we also try to
help people entering this topic so for
example we did a little Heaton here in
2023 and except of us these are all
people who measure stuff so they have no
clue about modeling and we Tred to
explain how to build a model how to run
a model on a HPC and yeah um I think
with this that was fun that was fun yeah
so but now we already done this is our
literature please ask
questions
[Applause]
thank you Martin ra and thank you Jann
bizo um if you have questions please
queue up at the
microphones um and also we take question
from the internet I would start with the
signal
Angel the internet is asking about two
sources of pollution what about vehicle
tires and what about if we all switch to
hydrogen and there's amonia everywhere
how does how do you see that impacting
the world yeah actually that was the
reason why I just showed um results for
NO2 concentrations because for example
when you introduce electric cars or
hybrid electric vehicles you you will
still have Tire where you will have um
particles from breaking from the tires
themselves so by introducing electric
cars we will only partially tackling the
problem of particulate metal pollution
so I think that answers a question yeah
and it's that tire and uh break wear is
I mean there are estimates in the
emission model so we have some factors
for different depending on the size and
weight of cars but these are really
really uncertain
and it's still a big question
mark thank you uh microphone number two
your question hello hello first of all
thank you for a great talk talk very
interesting one uh my question is is
when it comes to modeling air pollution
in Germany one of the biggest topics is
the shutting down of nuclear power
plants and then dependence on gas and
then shutting down of gas pipelines and
depending on coal have you done or have
you experimented with any modeling
around like reintroducing nuclear power
plants and how it would influence the
air pollution in the current climate
where the gas doesn't flow that much
anymore so that's not a study we've done
um let me think a second before I say
silly things but um no we didn't it it's
just that I mean of course I mean Cal
fired power plants it's the it's the
most polluting thing I mean it it emits
more radioactivity than a nuclear power
plant because of the cium in there and
um it is definitely pollution wise and
not wise decision um but I it's nothing
that would affect the German air quality
because the the cold fired power plants
it's it's really the the sulfur and
there uh we've had reduction of like 98%
because all the cold fired power plants
now have sulfur uh desulfuration so they
they reduce it before it gets out of the
thing so the coal is really a climate
thing with the CO2 mainly but it it
shouldn't be like a significant part of
what what's actually polluting you
that's much more from traffic
agriculture thank you thank you uh sign
Andel your question uh the community is
asking how about how are the models
impacted by different measurement cheses
is it better to buy like one very good
measurement station or many small DIY
almost on and can people get involved
helping with that that's actually a good
question and the the an is we need
everything in the end because it's
really important to have these reference
grade uh instruments which are really
expensive uh you can use these to
calibrate your your small DIY sensors so
you get an idea on how they perform and
how well they perform and then you can
distribute them spatially so you get a
better idea of of the spatial coverage
but still there are gaps in between and
then modeling comes into play so if
everything works together and interacts
together nicely then we get a really
good picture of what's actually going on
because as Visa said um sometimes it's
hard to trust models but it's also hard
to trust measurements so we need in the
end we need everything and I think we
can brainstorm about possibilities how
to work together yeah
sure thank you microphone number one
what is your question I by Distributing
the sensors um you get a really good
real time model I think is there any
researches regarding the blobs you call
them blops I think uh how to catch them
or how to clean them up because if they
are in metropoles maybe there is a
technique to to work with them so you
can collect the trash from floor but
maybe you can collect also some trash
from air with the blobs you mean the the
ship emission particle video yeah but
more in the metropoles not on the ocean
um yeah what's happening is that there's
now um I mean it started that so let me
let me start it's really crazy ships
they they drive with heavy fuel oil
mostly and oil it's trick it's it's
basically at room temperature it's not
liquid they they drive with for solid
and it's full with sulfur especially but
um a few years ago the the world
Maritime organization started
introducing sulfur reduction areas where
you were not allowed anymore to drive
with sulfur content and now actually is
that that's upcoming that's not there
yet there's now the nitrogen emission
areas where ships will be forced to
actually switch onto a liquefied
nitrogen gas and it's a super
interesting topic because uh having the
sulfur emissions away from people that's
really good but if we now use the
desized fuel that also means we're not
emitting sulfur above the Atlantic above
the Pacific and there's is a super
effective coolant as a as a particle so
um yeah because that's that's really
something that's again from the polyc
perspective a bit it's I think it's
crazy you have these these areas and
they are I don't know how many miles
away from the coastline but then there's
a point when you exit these these
coastline
this area you can again just burn
whatever you want so the regulation is
just valid when you're close to the
coast and this is as you as you saw that
doesn't make sense because the formation
happens also far away from the coast and
in
land but in the opposite way that you
have something like a smoking room where
they clean the air so you have a area
where you can create some pollution
which is not should not be our future
but um and then they have some technique
to clean to yeah but I mean you're
completely helpless it's gets
transported with the winds and diffusion
and so you could have some fancy
artificial trees everywhere I mean it's
it's really if there wouldn't be that
massive amount of manure and ammonia
emissions from the animal husbandry and
for the nitrogen oxides it's really
mostly the uh Vehicles traffic so if if
your Cloud plume from the ship comes on
coast and there is no pi Farm then also
there would probably be less particles
produced thank you for your answer uh
microphone number two your
question hello thank you for your
interesting talk I also had one of those
sensors in operation that you mentioned
that measure um pm2 and um pm10 2.5 and
pm10 and um what I saw in my data was
also the traffic patterns that you
mentioned it was very clear but um what
I also saw was um the high peak at the
end of the year coming from the
fireworks and I would um um ask you um
what is your position on a um B of
fireworks do you have any opinion on
that and given your knowledge also of
course I have a personal opinion on that
and I I don't like it I would ban it um
from a air quality perspective and EM
Mission modeling perspective it's really
interesting because we just don't take
it into account so whenever we we model
the January and the 1 of January and
also the 31st of the of the the last of
the year then we Al always have this
peak in our models when we not in our
models but in the measurements and when
we compare it we always we are far away
from it because we just don't take into
account because we are using these
temporal profiles to distribute
emissions but such things as holidays
and special occasions or like 500,000
people meeting to grill in the park or
whatever it's just not in our models
because it's so specific that we can't
model it in general well of course you
can do it you can do a specific study
about it but if you look at the whole
city or country or even the world then
such events just
disappear um yeah so no it's not in our
model and it's also very bad for cities
that are shaped like a pit like like
hustle or St and so on definitely yeah
yeah yeah we didn't talk about orography
yeah thank you for your answer Mone
number three your question hi so if you
spend a lot of time online you quickly
read about this new class of pollutants
the per fluorinated ALU substances or
the pasas and I was wondering if that is
relevant at all to your research in air
pollution or if it's rather on the turf
of water pollution and if it's relevant
if you already have the ability to
measure and model them actually we are
running a little group who's dealing
with this topic uh so we we have um did
you pay him to ask the question I didn't
thank you thank you for the question um
so as as we were introduced we are
pollution modelers so we are not
focusing only on air pollution we are
looking at many pollutants and not only
atmosphere but also in the ocean and
yeah so for peas we actually uh
published a global emission model for
pasas into rivers oceans and atmosphere
that covers the whole production period
from the 1950s to uh 2020 that's
available in this echad database where
there is also the ipcc emission um
databases are and I really love the pe's
topic because as modelers it's always
like the initial condition what's the
initial condition and we just start 950
the substance didn't exist it's like I
have an initial condition that thought
it would never happen I can die happy
now and um we we actually just uh we
have two PhD students we're supervising
and one is working on the atmospheric
icon model and the other on the the
ocean icon model and we're just um
kicking them not to have vacation and
finish the model space no no we're nice
supervisors and um so but yes we were
actually working on having an atmosphere
ocean coupled model where we can also
look at things like because there aets
once they're in the ocean they shouldn't
come back but then you can have sea
spray and it actually when the sea spray
evaporates you have a mechanism of
getting it wind driven back into the
atmosphere that's probably a factor in
the long range transport and now there's
like new Europe regulations coming up
that bends like 24 P first and so just
to add one more thing because we also do
measurements on mainly in water but also
some in the atmosphere and there are
some other groups around the world that
are doing that too so actually that's a
big problem with on on the agenda for
measurements and modeling and yeah we're
on it thank you for your answer uh I'm
afraid time's up are you still around
for people to contact you for for
further questions yes awesome you never
stopped
talking yeah
K thanks for your great talk thank
[Applause]
[Music]
you