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

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Presentation on theme: "EFFECTS OF AIR POLLUTANTS ON MATERIALS Peter Brimblecombe University of East Anglia Norwich UK."— Presentation transcript:

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

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

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

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

5 Atmospher e DamagelayerDamagelayer Material SO 2 gas SO 4 = SO 3 = SO 4 = Catalysts aerosol Catalysts material CALCIUM CARBONATE CALCIUM ALUMINOSILICATES CALCIUM CARBONATE CALCIUM ALUMINOSILICATES GYPSUM FORMATION GYPSUM Cristina Sabbioni

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

7 ARCHITECTURAL IMPACTS l Sulfation by SO 2 - limestone to gypsum l Gypsum: - more soluble - larger molecular volume Building dissolves and explodes...

8 ATMOSPHERIC DAMAGE TO LIMESTONES l Natural weathering important l SO 2 sorption and oxidation hard black sulfate crusts l Acid rain - white areas HNO 3 Acids SO 2 CO 2 Reddy et al, 1986 TIME OF WETNESS IMPORTANT

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

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

11 ENDING GOTHIC ARCHITECTURE l Detail attacked by air pollution l Architects favoured neo- classical styles l 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 l Surface must be wet l High corrosion after dry spells l NO2 did increase SO2 attack l No chloride effect CORROSION OF MILD STEEL Lloyd, 1995

13 IRON DAMAGE Fe = Fe e - Fe FeOOH Fe 3 O 4 8FeOOH + Fe e - = 3Fe 3 O 4 + 4H 2 O 3Fe 3 O O H 2 O = 9FeOOH How does SO 2 enhance corrosion rate? Fe 3 O 4 an electronic conductor FeSO 4 solution a Fe 2+ conductor FeOOH permeable to oxygen Sulfation FeSO 4

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

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 μm/year PREDICTED KARST WET DRY 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 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 Wrens time. BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)

20 ST PAULS BALUSTRADE RECESSION RATES (1718–1987) ST PAULS 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 l Reasonable agreement with model l St Pauls balustrade horizontal (green) – rapid recession so poor agreement St Pauls 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 Ackeroyds novel Hawksmoor.

23 BLAKNENING OF LONDON FACADES 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)

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 l Inverted U-shape curves of pollutants over time seen as economically driven l Pollutant concentrations in London follow a Kuznets curve l 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).

26 MODERN METALS l Although in the past copper formed slow well structured patinas - these were less stable when urban air was acidic l It may be in the 21 st 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 l 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 21 st C l Coal black buildings of the past with gypsum crusts l Contemporary soots l Managing building perceptions l Blackening a public pressure

31 WHITE TOWER like most great buildings often referred to as magnificent l However, creates a specific problem of perception… Its not white l Its old, ancient, naturally aged has the patina of time

32 COLOUR 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 (?) b-parameter (yellow) t-folding 93 days (ii) t/days Soiling (black) t-folding 160 days (i) Treated Limestone sheltered exposure

33 PERCEPTION OF CRUSTS l Light coloured European buildings l >900 visitors l Dirty? l Tone?

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

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

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

37 PREFERENCE

38 FRACTALS More acceptable patterns: those which delineate the architecture

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

40 INDOORS

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

42 HISTORIC INDOOR SULPHUR DIOXIDE British Museum London Natl Library Wales Aberystwyth

43 CUMULATIVE SULPHUR DEPOSITION British Museum London Natl Library Wales Aberystwyth

44 OPERATIONAL THRESHOLDS l Damage by the pollutant gas is slower than damage by other processes l Damage by the pollutant gas leads to an acceptable loss over planned survival

45 LEAD 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?

46 MECHANISMS & UNEXPECTED PRODUCTS Lead formate expected, but carbonates often found… especially plumbonacrite, Pb 10 (CO 3 ) 6 (OH) 6 O hydrocerussite, Pb 3 (CO 3 ) 2 (OH) 2 Pb(HCOO) 2 + H 2 O + CO 2 = 2HCOOH (g) + PbCO 3 Carbonate stabilised at low formic acid pressures HCHO + H 2 O 2

47 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 + H 2 O 2

48 SULFIDES AND SILVER Wool and many other materials generate sulfides which tarnish silver…. often not H 2 S! COS + Ag 2 O AgS + CO 2 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 AEH OPH

51 CLOTHING AS A SOURCE OF DUST

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

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

54 PROBLEM OF CEMENTATION l WHAT HAPPENS WHEN DUST IS LEFT l Biological l Chemical l 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 Humidity and pollutants may bind dust to underlying surfaces Cement microcrystalline calcites

57 SPEED of CEMENTATION Knole Dust Soil Dust House dust tends to be more hygroscopic

58 DIRTY DANCING

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

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

61 LOCATION OF STICKY SAMPERS EASTWEST SOUTH X X X X X X

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

63 CONCLUSIONS l Defining the appropriate materials is complicated by: l pollutant identification synergisms... and monitoring l what is damage issues l many targets l timescales and acummulation l This continues to be a challenge….


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