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Figure5Exposurechambersandculturedishes productive to least productive: ABS>Urethane >Nylon.From the second row to end in Table 2 shows gas composition measured by the gas detector tube systems were used with short-termquick-measuringdetectortubes.COandHCHOof UrethanewaslargerthanNylon，whileHCNproductionby NylonwaslargerthanUrethane.
The toxic gas composition is both scenario and material dependen.t HCN production exhibits 仕ong temperaturedependence.HCN ofUrethane increases with tempera加 re，whereasHCNofMelaminehasapeakat7000Cin air[12].Wearenowplaningtoin-sUumonitoringofHCNor toxicgasbyFTIRtocorelate白regastoxicityforA549
3.2 Morphologicalchangeandcelviability
Long-termexposureFigure6and7showthemorphological changeofA549a白erexposuretothredi汀erentgases;95%air with5%CO2 (controlcelcultureatmosphericcondition)，ai仕r (79% nitrogen and 21% oxygen) and the combustion ga出S
periodsぱ0f2μ4，48担 d72hours.TheA549celswereexposedto thee白 uentsproduced企omABS.Folowingexposureto95% airwith5%CO2，afterthetirneperiodsof24，48and72h，no morphologicalchange，asshowninFig.6(a)andFig.7(a)，was observedintheA549.Thecelsexposuretoair，asshownin Fig.6 (b)，shows that cel boundaries are obscure and or indistinguishab1ecomparedtocon仕01gas.Figure6(c)加 dFig.7 (c)showceldamage企omtoxicgasexposure.Itapearedthat the cel ls began to shrink in size and cel ls were ir regularly shapedandhadobscurecelboundaries.
SlOrt-termexposureLog-temlexposuretoABSdemonstrated thatA549celswereseverelydamagedwithin24h.Therefore， short-term measurements were conducted at the dif ferent exposuretirneperiodsof0.5，2and4hours.Theviabilityof celsexposedtothrediferentgaswerecomp紅 edtoalgroups each other. The A549 cel ls were exposed to the ef fluents produced企omABS.Thecelviabilityandlive/deadcelcount ineachtestisshowninFig.8.Folowingexposureto95%a仕 with 5 % C O2，A549cel l proliferation was observed after the tirneperiodsofO.5，2and4h，evenanincreaseinceldeath(96% to88%viable)wasdetectedoverthe0.5hperiod.Theexposure to air shows the excel lent cel l viability even 72 hours post exposure.A549 cel lswere exposed to the e田 uents produced from ABSto inducecel death at varioustime points.
Table2ComponentsofiregasbyG.D. (ppm)
Overtime，thecelsprogresed丘om84%viableattirne0.5hto lesthan20%viableby4hours.Figure9showsthecelviability and cel l live/dead cel l count at the dif ferent exposure time periodsof0.5，2and4hours.TheA549celswereexposedto the efluents produced 企om ABS，nylons，Urethane and Melamine.Thefolowingto氾cityra叫cingasobserved企omthe most toxic to the least toxic: ABS> Nylons>Urethane>Melan1ine.
Thee百ectsofthetwomaintoxicantsarewelunderstod，CO causesdeathbybindingstronglytohaemoglobin，preventing the仕 叩sportofoxygenfromthelungstothebody，whileboth CO and HCN inhibit metal containing enzymes， inc1udingcytochromoxidase，whichprovidesenergywithincels by reaction with oxygen.Our resu1ts exhibit the discrepancy betwenHCNgenerationrankingandcelviabilityranking.We nedfurtherinvestigationonothertoxicefectonA549.The extraction0白1RNA 企omdamagedA549andsucesivereal timePCRanalysismayatributetotheapoptosisofA549cels [13]
Firegas(ABS)
H2 0.06 0.0
24h 48h 72h
O2 13.0
19.0 21.0
78.0 78.1
(a)
5% CO2
Nz 82.0 CO 6.0
3.0 0.03
z HCN
。
125a 0.0 a:Relativevalueinanalysisongaschromatography
Table1ComponentsoffiregasbyG.C.(ppm)
(b) Air
(c)
Fire gas
ABS Nylon HC~ 125 8.3
HCNb n.m. 25 a:gaschromatographs，b:Gasdetectortubcsystems，c:not-me出 ured
COzb n町1.c 23000
CO n.m 30 900
b。。 NH3b n.m.
n.m. nロ1. n.m. n.m.
HCHO n.m. 8 46 b。
5%C0 Air
2
。
Urethane
31.3 n.m.
35500 n.m.
Melamine
(a)
5% CO2
Air
(c)
Fire gas
24h 48h 72h
Figure6MicrophotographsofA549celsafterexposureto the combustion gas generated from A B S (X 10 0)
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