EFFECTS EFFECTS OFOF AIR POLLUTANTS AIR POLLUTANTS ONON MATERIALSMATERIALS

Peter BrimblecombePeter Brimblecombe

University of East AngliaUniversity of East Anglia

Norwich UKNorwich UK

FACTORS THAT DAMAGE FACTORS THAT DAMAGE MONUMENTS AND CULTURAL MONUMENTS AND CULTURAL HERITAGEHERITAGE

War and vandalism Urban development Architectural styles Poor restoration Earthquakes and storms Climate and weathering Air pollution

Appear as:

impulses

cycles

cumulative doses

-5

0

5

10

15

20

25

30

1600 1700 1800 1900 2000 2100

Tem

per

atu

re/C

HOTTEST MONTH

COLDEST MONTH

CETRHADCM3

PAST AND FUTUREPAST AND FUTURECENTRAL ENGLAND TEMPERATURES CENTRAL ENGLAND TEMPERATURES

0

10

20

30

40

50

1950 2000 2050 2100

cycl

es/y

ear

Central England/Europe

FREEZE THAW CYCLESFREEZE THAW CYCLES

Frost shattering of porous stone

Central England

Czech Republic

Atm

osp

he

reAtm

osp

he

re

Dam

age

Dam

age

layer

layer

Dam

age

Dam

age

layer

layer

Mate

rial

Mate

rial

SO2

gas SO4=

SO3=SO3= SO4

=SO4=

Catalysts aerosol Catalysts aerosol

Catalysts material Catalysts material

CALCIUM CARBONATECALCIUM ALUMINOSILICATES

CALCIUM CARBONATECALCIUM ALUMINOSILICATES

GYPSUM FORMATION

GYPSUMGYPSUM

Cristina Sabbioni

SULFATIONSULFATIONSULFATIONSULFATION

GYPSUM S-compounds from the

atmosphere

GYPSUM S-compounds from the

atmosphere

CARBONACEOUS PARTICLESCARBONACEOUS PARTICLES

Cristina Sabbioni

ARCHITECTURAL IMPACTSARCHITECTURAL IMPACTS

Sulfation by SO2

- limestone to gypsum Gypsum:

- more soluble

- larger molecular

volume

Building dissolves and explodes...

ATMOSPHERIC DAMAGE TO ATMOSPHERIC DAMAGE TO LIMESTONESLIMESTONES

Natural weathering important

SO2 sorption and oxidation hard black sulfate crusts

Acid rain - white areas HNO3

Acids

SO2

CO2

Reddy et al, 1986

TIME OF WETNESS IMPORTANT

ARCHITECTURAL IMPACTSARCHITECTURAL IMPACTS

Modern urban atmospheres deposit less sulfur (phytotoxic) more nitrate (nutrient)

Encourage biological damage

ARCHITECTURAL ARCHITECTURAL IMPACTSIMPACTS

Modern crusts from diesel are rich in organics - crusts may be polymers

POTENTIAL PHOTOSENSITIZERS

ENDING GOTHIC ENDING GOTHIC ARCHITECTUREARCHITECTURE

Detail attacked by air pollution Architects favoured neo-classical

styles Basil Champneys’ late Gothic

John Rylands Library (1900) - restrained the external design

- dark coloured materials

- Gothic interiors rather than exteriors

BOWLER, C & BRIMBLECOMBE, P. Journal of Design History, 13, 175-191 (2000)

DAMAGE TO METALSDAMAGE TO METALS

Surface must be wet

High corrosion after dry spells

NO2 did increase SO2 attack

No chloride effect 0 0.05 0.1 0.15

Industrial

Town

Rural

mm/year

1987-81933-60

CORROSION OF MILD STEEL

Lloyd, 1995

IRON DAMAGEIRON DAMAGE

Fe = Fe2+ + 2e- Fe

FeOOH

Fe3O4

8FeOOH + Fe2+ + 2e-

= 3Fe3O4 + 4H2O

3Fe3O4 + 0.75O2 + 4.5H2O

= 9FeOOH

How does SO2 enhance corrosion rate?

Fe3O4 an electronic

conductor

FeSO4 solution a Fe2+ conductor

FeOOH permeable to oxygen

Sulfation

FeSO4

8

12

16

1100 1300 1500 1700 1900 2100

Year

T/ C

.

500

550

600

650

1100 1300 1500 1700 1900 2100

Rai

nfa

ll/m

m .

CLIMATE INPUTCLIMATE INPUTEstimated from Netherlands

van Engelen et al., 2001Instrumental CETR

HadCM3a2

HadCM3a2

Lamb Wet/Dry IndicesKew

Heat Island

CARBON DIOXIDE CARBON DIOXIDE CONCENTRATIONCONCENTRATION

250

350

450

550

650

750

1100 1300 1500 1700 1900 2100

Year

CO

2/p

pm

.

POLLUTANT CONCENTRATIONPOLLUTANT CONCENTRATIONFUEL IMPORTS TO LONDONFUEL IMPORTS TO LONDON

0

100

200

300

400

1100 1300 1500 1700 1900 2100

Year

SO

2-H

NO

3/p

pb

.

SO2

HNO3*100

BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, 463-471 (2008)

MODELLED RECESSIONMODELLED RECESSIONLIPFERTLIPFERT

μμm/yearm/year

PREDICTED

KARST WET

DRY

BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, 463-471 (2008)

WESTMINSTER WESTMINSTER ABBEYABBEY

"… you rather behold the skeleton of a church than any great comeliness in her appearance, being so shrivelled and parcht by the continual blasts of the northern winds, to which she stands exposed, as also the continual smoaks of the sea-coal which are of a corroding and fretting quality…".

Keepe (1682)

COMPARING THE COMPARING THE MODEL WITH DATAMODEL WITH DATA

“…the unhappy choice of materials: the stone is much decayed four inches (~100 mm) deep and falls off perpetually in great scales.”

Wren Report on Westminster Abbey to Francis Atterburg (1713)

The model suggests ~ 8 mm of weathering on Westminster accumulated up to Wren’s time.

BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, 463-471 (2008)

RECESSION RATES (1718–1987)ST PAUL’S BALUSTRADEST PAUL’S BALUSTRADE

observed lead plugs 81 μm/year

model 32 μm/year

Again as with the Karst landscapes the horizontal surfaces are likely to recede at a greater rate

BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, 463-471 (2008)

MODERN MEASUREMENTSMODERN MEASUREMENTSDECLINING RECESSION IN LONDONDECLINING RECESSION IN LONDON

Reasonable agreement with model St Paul’s balustrade horizontal (green) –

rapid recession so poor agreement

St Paul’sSt Paul’s

PREDICTED

μμm/yearm/year

BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, 463-471 (2008)

COAL-BLACK COAL-BLACK LONDONLONDON

“…from what Purse are we building these churches, Walter?”“From the Imposicion on Coles.”“And are the Coles not the blackest Element,

which with their Smoak hide the Sunne?”Peter Ackeroyd’s novel Hawksmoor.

BLAKNENING OF LONDON FACADESBLAKNENING OF LONDON FACADES

0

10

20

30

40

1100 1300 1500 1700 1900 2100

Year

Bla

cken

ing

%p

er m

on

th

BRIMBLECOMBE & GROSSI Millennium-long damage to building materials in London, Science of the Total Environment 407, 1354 (2009).

“For smoke, which is the London ivy, had so wreathed itself round Peffer's…dwelling-place that the affectionate parasite quite overpowered the parent tree.”

Charles Dickens Bleak House (1852/3)

CORROSION OF IRONCORROSION OF IRONcorroding the very Iron-bars… with those piercing and acrimonious Spirits which accompany its Sulphure; and executing more in one year, than expos'd to the pure Aer of the Country … in some hundreds” Fumifugium (1661)

BRIMBLECOMBE & GROSSI Millennium-long damage to building materials in London, Science of the Total Environment 407, 1354 (2009).

KUZNETS RELATIONSHIPKUZNETS RELATIONSHIP

Inverted U-shape curves of pollutants over time seen as economically driven

Pollutant concentrations in London follow a Kuznets curve

Such curves particularly evident for pollutants creating localised problems that offer local benefits via regulation. INCOME PER CAPITA

INEQUALITY

INDUSTRIALIZATION

POLLUTION

BRIMBLECOMBE & GROSSI Millennium-long damage to building materials in London, Science of the Total Environment 407, 1354 (2009).

MODERN METALSMODERN METALS

Although in the past copper formed slow well structured patinas - these were less stable when urban air was acidic

It may be in the 21st C that copper and aluminium are sensitive to ozone.

NEW MATERIALSNEW MATERIALS

Modern materials, especially the wide use of polymers and fillers may need us to consider other pollutants - most importantly the oxidants which attack double bonds

Relatively few contemporary studies...

OTHER METALS OTHER METALS

Carlota/Alessandra/TSW

BRIMBLECOMBE & GROSSI Potential damage to modern building materials from

21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.

POLYMERS – POLYMERS – EFFECT OF OZONEEFFECT OF OZONE

BRIMBLECOMBE & GROSSI Potential damage to modern building materials from

21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.

BLACKENING IN 21BLACKENING IN 21stst C C

Coal black buildings of the past with gypsum crusts

Contemporary soots Managing building

perceptions Blackening a public

pressure

WHITE TOWERWHITE TOWERlike most great buildings often like most great buildings often

referred to as magnificentreferred to as magnificent

However, creates a specific problem of perception…

“It’s not white”

“It’s old, ancient, naturally aged” has the “patina of time”

COLOURCOLOUR

Esbert el al 1997

A hint of different processes: soiling and colour change may have different rates: (i) soiling reflects soot deposition (ii) yellow faster sulphation (?)

8.5

9

9.5

10

10.5

11

11.5

0 100 200 300 400

b-parameter (yellow)

t-folding 93 days

(ii)

72

74

76

78

80

82

84

86

88

0 100 200 300 400t/days

Soiling (black)

t-folding 160 days

(i)

Treated Limestone sheltered exposure

PERCEPTIONPERCEPTIONOF CRUSTS OF CRUSTS Light coloured European

buildings >900 visitors Dirty? Tone?

1 7 8 9 10 11 123 4 5 62

THRESHOLDSTHRESHOLDSPERCEIVED REFLECTANCE vs PERCEIVED REFLECTANCE vs ELEMENTAL CARBONELEMENTAL CARBON

Math

0

20

40

60

80

100

0 2 4 6 8 10 12

EC ug/m3

Lp%

Desired/PerceivedStatistical

Admin UAdmin P

lighter or darker, but not like that

Soiling perception:

Disquiet over the appearance of facades increases with the amount of soiling. Darkening Loss of reflectance

PATTERNS OF SOILINGPATTERNS OF SOILING

Group A: Soiling in and around the window

Group B: Soiling more dispersed on

the wall

Sixteen in all…

PREFERENCEPREFERENCE

FRACTALSFRACTALS

0

2

4

6

8

1 1.1 1.2 1.3 1.4Fractal dimension

Ra

nk

av

era

ge

(a

-im

ag

es

)More acceptable patterns: those which

delineate the architecture

PATINA AESTHETICSPATINA AESTHETICS

-1.5

-1

-0.5

0

0.5

1

1.5

0 20 40 60 80 100

PATINATION

DAMAGE

TIME

Surface changes over time may not all be negative

Kari Kivisalo

INDOORSINDOORS

PERSIAN LEATHER SADDLE BAGSPERSIAN LEATHER SADDLE BAGS Iron or green copper pigment

at leather surface may catalyze sulfuric acid formation

Cu Fe S

CROSS-SECTION

DAMAGED SADDLE BAGS

Deutsches Leder und Schuhmuseum

HISTORIC INDOOR HISTORIC INDOOR SULPHUR DIOXIDESULPHUR DIOXIDE

British MuseumLondon

Nat’l Library WalesAberystwyth

CUMULATIVE CUMULATIVE SULPHUR DEPOSITIONSULPHUR DEPOSITION

British MuseumLondon

Nat’l Library WalesAberystwyth

OPERATIONAL THRESHOLDS OPERATIONAL THRESHOLDS

Damage by the pollutant gas is slower than damage by other processes

Damage by the pollutant gas leads to an acceptable loss over planned survival

LEAD CORROSIONLEAD CORROSION

photo © Christoph Waller, 2001

A lead weight severely corroding, due to chipboard bottom of show case.

from an Austrian museum

…a long departed pollutant?

MECHANISMS & UNEXPECTED MECHANISMS & UNEXPECTED PRODUCTSPRODUCTS

Lead formate expected, but carbonates often found… especially

plumbonacrite, Pb10(CO3)6(OH)6O

hydrocerussite, Pb3(CO3)2(OH)2

Pb(HCOO)2 + H2O + CO2

= 2HCOOH(g) + PbCO3

Carbonate stabilised at low formic acid

pressures

HCHO + H2O2

REACTIONS IN MUSEUM CASES REACTIONS IN MUSEUM CASES

Lead in a formaldehyde atmosphere only corrodes on oxidation to formic acid...

HCHO

Michele Raychaudhuri

SYNERGISMS

Oxidation potential not concentration relevant to

damage…

HCHO + H2O2

SULFIDES AND SILVER SULFIDES AND SILVER Wool and many other materials generate

sulfides which tarnish silver….often not H2S!

COS + Ag2O AgS + CO2

Pollutants not the same as those that impact health

Early silver bicycle trophy

http://www.juliaauctions.com/

PEROXIDE ATTACK - PEROXIDE ATTACK - PHOTOGRAPHS PHOTOGRAPHS

Right print was pinned to a chipboard notice board for six months,

Morten Ryhl-Svendsen

IMPACT OF VISITOR NUMBERSIMPACT OF VISITOR NUMBERSon DUST DEPOSITon DUST DEPOSIT

0

2

4

6

0 50000 100000

Visitors/exposure period

/Gs

HCP

AEH

OPH

CLOTHING AS A SOURCE OF DUSTCLOTHING AS A SOURCE OF DUST

BOOKTEAM OBSERVATIONS in BOOKTEAM OBSERVATIONS in FELBRIGGFELBRIGG LIBRARY LIBRARY

EAST WEST

SOUTH

VERYDUSTY

FAIRLYDUSTY

BITDUSTY

VISITORS AT EAST WALL SHEDDING DUST

DUST – THE MOVIE DUST – THE MOVIE (RATED R)(RATED R)

Ickworth House Dining room for 1 week

PROBLEMPROBLEM OF CEMENTATION OF CEMENTATION

WHAT HAPPENS WHEN DUST IS LEFT

Biological Chemical Physical

is humidity the unifying driver?

BACTERIAL EXOPOLYMERSBACTERIAL EXOPOLYMERS

Silk fibers and bacteria after two months of growth in high humidity.

SEMs: A. Tarnowski & C. McNamara Appl.Bio. DEAS Harvard University

CHEMICAL CEMENTATION CHEMICAL CEMENTATION

Humidity and pollutants may bind dust to underlying surfaces

Cement microcrystalline calcites

0

0.4

0.8

1.2

1.6

0 5 10 15 20

Exposure time (days)

Du

st o

n fib

re (m

g)

SPEED of CEMENTATIONSPEED of CEMENTATION

Knole Dust

Soil Dust

House dust tends to be more “hygroscopic”

DIRTY DANCINGDIRTY DANCING

100

200

300

400

30 35 40 45 50 55 60 65

RH

Ope

ning

/mic

rons

AESTHETICSAESTHETICSBOOKTEAM SURVEYBOOKTEAM SURVEY

Assessed Assessed shelves as:shelves as:

CleanCleanBit DirtyBit DirtyFairly DirtyFairly DirtyVery DirtyVery Dirty

Caroline Bendix

BOOKTEAM OBSERVATIONSBOOKTEAM OBSERVATIONS

EAST WEST

SOUTH

VERYDUSTY

FAIRLYDUSTY

BITDUSTY

VISITORS AT EAST WALL SHEDDING DUST

LOCATION OF STICKY SAMPERSLOCATION OF STICKY SAMPERS

EAST WEST

SOUTH

X

X

X

X

X X

VERYDUSTY

above 7% bookshelves seem to demand cleaning…

3% in rooms?

FAIRLY DUSTY

BIT DUSTY

4

6

8

10

12

14

0 1 2 3 4 5 6 7 8

Rank

% C

ove

rag

e

CLEANEST DUSTIEST

RELATING PERCEPTIONS TO RELATING PERCEPTIONS TO MEASUREMENTSMEASUREMENTS

Ranking byBook team

Me

as

ure

men

ts

CONCLUSIONSCONCLUSIONS

Defining the appropriate materials is complicated by:

pollutant identification synergisms... and monitoring

what is damage issues many targets timescales and acummulation

This continues to be a challenge….