Presentation on theme: "EFFECTS OF AIR POLLUTANTS ON MATERIALS"— Presentation transcript:
1EFFECTS OF AIR POLLUTANTS ON MATERIALS Peter BrimblecombeUniversity of East AngliaNorwich UKEFFECTS OF AIR POLLUTANTS ON MATERIALS
2FACTORS THAT DAMAGE MONUMENTS AND CULTURAL HERITAGE War and vandalismUrban developmentArchitectural stylesPoor restorationEarthquakes and stormsClimate and weatheringAir pollutionAppear as:impulsescyclescumulative doses
3PAST AND FUTURE CENTRAL ENGLAND TEMPERATURES HOTTEST MONTHHADCM3CETRCOLDEST MONTH
4FREEZE THAW CYCLES Czech Republic Central England Central England/EuropeFREEZE THAW CYCLESCzech RepublicCentral EnglandFrost shattering of porous stone
10ARCHITECTURAL IMPACTS Modern crusts from diesel are rich in organics - crusts may be polymersPOTENTIALPHOTOSENSITIZERS
11ENDING GOTHIC ARCHITECTURE Detail attacked by air pollutionArchitects favoured neo-classical stylesBasil Champneys’ late Gothic John Rylands Library (1900)- restrained the external design- dark coloured materials- Gothic interiors rather than exteriorsBOWLER, C & BRIMBLECOMBE, P.Journal of Design History, 13, (2000)
12DAMAGE TO METALS Surface must be wet High corrosion after dry spells CORROSION OF MILD STEELSurface must be wetHigh corrosion after dry spellsNO2 did increase SO2 attackNo chloride effectLloyd, 1995
13IRON DAMAGE How does SO2 enhance corrosion rate? Sulfation FeSO4FeOOH permeable to oxygen3Fe3O O H2O= 9FeOOHFe3O4 an electronic conductorFeFeOOHFe3O48FeOOH + Fe e-= 3Fe3O4 + 4H2OFeSO4 solution a Fe2+ conductorFe = Fe e-
14Estimated from Netherlands CLIMATE INPUTEstimated from Netherlandsvan Engelen et al., 2001Instrumental CETRHeat IslandHadCM3a2KewLamb Wet/Dry IndicesHadCM3a2
16POLLUTANT CONCENTRATION FUEL IMPORTS TO LONDON BRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)
17MODELLED RECESSION LIPFERT KARSTWETDRYμm/yearPREDICTEDBRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)
18WESTMINSTER 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)
19COMPARING 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)
20RECESSION RATES (1718–1987) ST PAUL’S BALUSTRADE observed lead plugs 81 μm/yearmodel 32 μm/yearAgain as with the Karst landscapes the horizontal surfaces are likely to recede at a greater rateBRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)
21MODERN MEASUREMENTS DECLINING RECESSION IN LONDON Reasonable agreement with modelSt Paul’s balustrade horizontal (green) – rapid recession so poor agreementSt Paul’sPREDICTEDμm/yearBRIMBLECOMBE & GROSSI Millennium-long recession of limestone facades in London Environmental Geology 56, (2008)
22COAL-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.
23BLAKNENING 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).
24CORROSION 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).
25KUZNETS RELATIONSHIPINDUSTRIALIZATIONPOLLUTIONINCOME PER CAPITAINEQUALITYInverted U-shape curves of pollutants over time seen as economically drivenPollutant concentrations in London follow a Kuznets curveSuch 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).
26MODERN METALSAlthough in the past copper formed slow well structured patinas - these were less stable when urban air was acidicIt may be in the 21st C that copper and aluminium are sensitive to ozone.
27NEW MATERIALSModern materials, especially the wide use of polymers and fillers may need us to consider other pollutants - most importantly the oxidants which attack double bondsRelatively few contemporarystudies...
28OTHER METALS Carlota/Alessandra/TSW BRIMBLECOMBE & GROSSI Potential damage to modern building materials from 21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.
29POLYMERS – EFFECT OF OZONE BRIMBLECOMBE & GROSSI Potential damage to modern building materials from 21st century air pollution, TheScientificWorldJOURNAL (2010) 10, 116–125.
30BLACKENING IN 21st CCoal black buildings of the past with gypsum crustsContemporary sootsManaging building perceptionsBlackening a public pressure
31WHITE 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”
32COLOURTreated Limestonesheltered exposuret/daysSoiling (black)t-folding160 days(i)b-parameter (yellow)t-folding93 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
33Light coloured European buildings >900 visitors Dirty? Tone? PERCEPTION OF CRUSTSLight coloured European buildings>900 visitorsDirty?Tone?178910111234562
34THRESHOLDS PERCEIVED REFLECTANCE vs ELEMENTAL CARBON Desired/Perceived MathDesired/PerceivedStatisticalAdmin UAdmin P
35Soiling perception:Disquiet over the appearance of facades increases with the amount of soiling. Darkening Loss of reflectancelighter or darker, but not like that
36PATTERNS OF SOILING Sixteen in all… Group A: Soiling in and around the windowGroup B: Soiling more dispersed on the wallSixteen in all…
41PERSIAN LEATHER SADDLE BAGS Iron or green copper pigment at leather surface may catalyze sulfuric acid formation100mCROSS-SECTIONSFeCuDAMAGED SADDLE BAGSDeutsches Leder und Schuhmuseum
42HISTORIC INDOOR SULPHUR DIOXIDE British MuseumLondonAssumed 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 WalesAberystwyth
43CUMULATIVE SULPHUR DEPOSITION British MuseumLondonThe 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 WalesAberystwyth
44OPERATIONAL THRESHOLDS Damage by the pollutant gas is slower than damage by other processesDamage by the pollutant gas leads to an acceptable loss over planned survival
46MECHANISMS & UNEXPECTED PRODUCTS Lead formate expected, but carbonates often found… especially plumbonacrite, Pb10(CO3)6(OH)6O hydrocerussite, Pb3(CO3)2(OH)2Pb(HCOO)2 + H2O + CO2= 2HCOOH(g) + PbCO3Carbonate stabilised at low formic acid pressuresHCHO + H2O2
47REACTIONS IN MUSEUM CASES Lead in a formaldehyde atmosphere only corrodes on oxidation to formic acid...Michele RaychaudhuriHCHOOxidation potential not concentration relevant to damage…HCHO + H2O2SYNERGISMS
48SULFIDES AND SILVER COS + Ag2O = AgS + CO2 Wool and many other materials generate sulfides which tarnish silver…. often not H2S!COS + Ag2O = AgS + CO2Pollutants not the same as those that impact healthEarly silverbicycle trophy
49PEROXIDE ATTACK - PHOTOGRAPHS Right print was pinned to a chipboard notice board for six months,Morten Ryhl-Svendsen
50IMPACT OF VISITOR NUMBERS on DUST DEPOSIT HCPOPHAEH
52BOOKTEAM OBSERVATIONS in FELBRIGG LIBRARY VERYDUSTYFAIRLYBITEASTWESTSOUTHVISITORS AT EASTWALL SHEDDING DUST
53DUST – THE MOVIE (RATED R) Ickworth House Dining room for 1 week
54PROBLEM OF CEMENTATION WHAT HAPPENS WHEN DUST IS LEFTBiologicalChemicalPhysicalis humidity the unifying driver?
55BACTERIAL EXOPOLYMERS Silk fibers and bacteria after two months of growth in high humidity.SEMs: A. Tarnowski & C. McNamara Appl.Bio. DEAS Harvard University
56CHEMICAL CEMENTATIONCement microcrystalline calcitesHumidity and pollutants may bind dust to underlying surfaces
57SPEED of CEMENTATION House dust tends to be more “hygroscopic” Knole DustSoil DustHouse 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.
62RELATING PERCEPTIONS TO MEASUREMENTS VERYDUSTYabove 7% bookshelves seem to demand cleaning…3% in rooms?FAIRLY DUSTYBIT DUSTYCLEANEST DUSTIESTMeasurementsRanking byBook team
63CONCLUSIONS Defining the appropriate materials is complicated by: pollutant identification synergisms... and monitoringwhat is damage issuesmany targetstimescales and acummulationThis continues to be a challenge….