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EFFECTS OF AIR POLLUTANTS ON MATERIALS

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Presentation on theme: "EFFECTS OF AIR POLLUTANTS ON MATERIALS"— Presentation transcript:

1 EFFECTS OF AIR POLLUTANTS ON MATERIALS
Peter Brimblecombe University of East Anglia Norwich UK EFFECTS OF AIR POLLUTANTS ON MATERIALS

2 FACTORS THAT DAMAGE MONUMENTS AND CULTURAL HERITAGE
War and vandalism Urban development Architectural styles Poor restoration Earthquakes and storms Climate and weathering Air pollution Appear as: impulses cycles cumulative doses

3 PAST AND FUTURE CENTRAL ENGLAND TEMPERATURES
HOTTEST MONTH HADCM3 CETR COLDEST MONTH

4 FREEZE THAW CYCLES Czech Republic Central England
Central England/Europe FREEZE THAW CYCLES Czech Republic Central England Frost shattering of porous stone

5 CALCIUM ALUMINOSILICATES
GYPSUM FORMATION SO2 gas SO4= Atmosphere Catalysts aerosol SO4= SO3= Damage layer GYPSUM Catalysts material CALCIUM CARBONATE CALCIUM ALUMINOSILICATES Material Cristina Sabbioni

6 SULFATION GYPSUM  S-compounds from the atmosphere
CARBONACEOUS PARTICLES Cristina Sabbioni

7 ARCHITECTURAL IMPACTS
Sulfation by SO2 - limestone to gypsum Gypsum: - more soluble - larger molecular volume Building dissolves and explodes...

8 ATMOSPHERIC DAMAGE TO LIMESTONES
TIME OF WETNESS IMPORTANT Natural weathering important SO2 sorption and oxidation hard black sulfate crusts Acid rain - white areas SO2 CO2 Acids HNO3 Reddy et al, 1986

9 ARCHITECTURAL IMPACTS
Modern urban atmospheres deposit less sulfur (phytotoxic) more nitrate (nutrient) Encourage biological damage

10 ARCHITECTURAL IMPACTS
Modern crusts from diesel are rich in organics - crusts may be polymers POTENTIAL PHOTOSENSITIZERS

11 ENDING GOTHIC ARCHITECTURE
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, (2000)

12 DAMAGE TO METALS Surface must be wet High corrosion after dry spells
CORROSION OF MILD STEEL Surface must be wet High corrosion after dry spells NO2 did increase SO2 attack No chloride effect Lloyd, 1995

13 IRON DAMAGE How does SO2 enhance corrosion rate? Sulfation
FeSO4 FeOOH permeable to oxygen 3Fe3O O H2O = 9FeOOH Fe3O4 an electronic conductor Fe FeOOH Fe3O4 8FeOOH + Fe e- = 3Fe3O4 + 4H2O FeSO4 solution a Fe2+ conductor Fe = Fe e-

14 Estimated from Netherlands
CLIMATE INPUT Estimated from Netherlands van Engelen et al., 2001 Instrumental CETR Heat Island HadCM3a2 Kew Lamb Wet/Dry Indices HadCM3a2

15 CARBON DIOXIDE CONCENTRATION

16 POLLUTANT CONCENTRATION FUEL IMPORTS TO LONDON
BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)

17 MODELLED RECESSION LIPFERT
KARST WET DRY μ m/year PREDICTED BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)

18 WESTMINSTER ABBEY "… 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)

19 COMPARING THE MODEL WITH DATA
The model suggests ~ 8 mm of weathering on Westminster accumulated up to Wren’s time. “…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) BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)

20 RECESSION RATES (1718–1987) ST 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, (2008)

21 MODERN MEASUREMENTS DECLINING RECESSION IN LONDON
Reasonable agreement with model St Paul’s balustrade horizontal (green) – rapid recession so poor agreement St Paul’s PREDICTED μ m/year BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)

22 COAL-BLACK LONDON “…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.

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

24 CORROSION OF IRON corroding 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).

25 KUZNETS RELATIONSHIP INDUSTRIALIZATION POLLUTION INCOME PER CAPITA INEQUALITY 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. BRIMBLECOMBE & GROSSI Millennium-long damage to building materials in London, Science of the Total Environment 407, 1354 (2009).

26 MODERN 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.

27 NEW 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...

28 OTHER METALS Carlota/Alessandra/TSW
BRIMBLECOMBE & GROSSI Potential damage to modern building materials from 21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.

29 POLYMERS – EFFECT OF OZONE
BRIMBLECOMBE & GROSSI Potential damage to modern building materials from 21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.

30 BLACKENING IN 21st C Coal black buildings of the past with gypsum crusts Contemporary soots Managing building perceptions Blackening a public pressure

31 WHITE TOWER like most great buildings often referred 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”

32 COLOUR Treated Limestone sheltered exposure t/days Soiling (black) t-folding 160 days (i) b-parameter (yellow) t-folding 93 days (ii) A hint of different processes: soiling and colour change may have different rates: (i) soiling reflects soot deposition (ii) yellow faster sulphation (?) Esbert el al 1997

33 Light coloured European buildings >900 visitors Dirty? Tone?
PERCEPTION OF CRUSTS Light coloured European buildings >900 visitors Dirty? Tone? 1 7 8 9 10 11 12 3 4 5 6 2

34 THRESHOLDS PERCEIVED REFLECTANCE vs ELEMENTAL CARBON Desired/Perceived
Math Desired/Perceived Statistical Admin U Admin P

35 Soiling perception: Disquiet over the appearance of facades increases with the amount of soiling. Darkening Loss of reflectance lighter or darker, but not like that

36 PATTERNS OF SOILING Sixteen in all…
Group A: Soiling in and around the window Group B: Soiling more dispersed on the wall Sixteen in all…

37 PREFERENCE

38 More acceptable patterns: those which delineate the architecture
FRACTALS More acceptable patterns: those which delineate the architecture

39 PATINA AESTHETICS Surface changes over time may not all be negative
PATINATION DAMAGE TIME Kari Kivisalo

40 INDOORS

41 PERSIAN LEATHER SADDLE BAGS
Iron or green copper pigment at leather surface may catalyze sulfuric acid formation 100m CROSS-SECTION S Fe Cu DAMAGED SADDLE BAGS Deutsches Leder und Schuhmuseum

42 HISTORIC INDOOR SULPHUR DIOXIDE
British Museum London Assumed I/O ratios of A very low value because these were storage rooms with little circulation and highly absorbent rooms with high surface areas. Nat’l Library Wales Aberystwyth

43 CUMULATIVE SULPHUR DEPOSITION
British Museum London The units here are gram/square metre. It is probably too high as it assumes that the deposition velocity does not decline over time. (Vd 3mm/s) Some detailed thoughts on the real book bindings. Over the exposure period of the leathers at the libraries (60 years from the 1930s) it is estimated that 5g/m2 and 99 g/m2 were deposited at NLW and BM. In terms of leather this means 1% and 19.8% S should be present in NLW and BM. Analysis of leather suggests 1.1% and 7.6% at NLW and BM. It looks as of deposition at BM has slowed down. Enabled standards to be set on the basis that at NLW the books were servicable, but at BM they were not. Nat’l Library Wales Aberystwyth

44 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

45 LEAD CORROSION …a long departed pollutant?
A lead weight severely corroding, due to chipboard bottom of show case. from an Austrian museum …a long departed pollutant? photo © Christoph Waller, 2001

46 MECHANISMS & UNEXPECTED PRODUCTS
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

47 REACTIONS IN MUSEUM CASES
Lead in a formaldehyde atmosphere only corrodes on oxidation to formic acid... Michele Raychaudhuri HCHO Oxidation potential not concentration relevant to damage… HCHO + H2O2 SYNERGISMS

48 SULFIDES AND SILVER COS + Ag2O = AgS + CO2
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

49 PEROXIDE ATTACK - PHOTOGRAPHS
Right print was pinned to a chipboard notice board for six months, Morten Ryhl-Svendsen

50 IMPACT OF VISITOR NUMBERS on DUST DEPOSIT
HCP OPH AEH

51 CLOTHING AS A SOURCE OF DUST

52 BOOKTEAM OBSERVATIONS in FELBRIGG LIBRARY
VERY DUSTY FAIRLY BIT EAST WEST SOUTH VISITORS AT EAST WALL SHEDDING DUST

53 DUST – THE MOVIE (RATED R)
Ickworth House Dining room for 1 week

54 PROBLEM OF CEMENTATION
WHAT HAPPENS WHEN DUST IS LEFT Biological Chemical Physical is humidity the unifying driver?

55 BACTERIAL EXOPOLYMERS
Silk fibers and bacteria after two months of growth in high humidity. SEMs: A. Tarnowski & C. McNamara Appl.Bio. DEAS Harvard University

56 CHEMICAL CEMENTATION Cement microcrystalline calcites Humidity and pollutants may bind dust to underlying surfaces

57 SPEED of CEMENTATION House dust tends to be more “hygroscopic”
Knole Dust Soil Dust House dust tends to be more “hygroscopic” Even dust without any added materials, the amount of dust adhesion at 98% high humidity is much higher than that of 35% low humidity condition. It shows that there is a clear relationship between the mass of particulate material which becomes attached to fibres and relative humidity.

58 DIRTY DANCING

59 AESTHETICS BOOKTEAM SURVEY
Assessed shelves as: Clean Bit Dirty Fairly Dirty Very Dirty Caroline Bendix

60 BOOKTEAM OBSERVATIONS
VERY DUSTY FAIRLY BIT EAST WEST SOUTH VISITORS AT EAST WALL SHEDDING DUST

61 LOCATION OF STICKY SAMPERS
EAST WEST SOUTH X X X X X X

62 RELATING PERCEPTIONS TO MEASUREMENTS
VERY DUSTY above 7% bookshelves seem to demand cleaning… 3% in rooms? FAIRLY DUSTY BIT DUSTY CLEANEST DUSTIEST Measurements Ranking by Book team

63 CONCLUSIONS 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….


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