Constituents of Tobacco ebooksclub.org Tobacco or Health Physiological and Social Damages Caused by Tobacco Smoking Second Edition
Table 3.2
Selectedcarcinogensintobaccosmokeofnon-iltercigarettesNFC Agent
Concentration NFC
IARCevaluation,evidenceofcarcinogenityin Labanimals
Humans Group
PAH Benzaanthracene
20–70ng S
2° Benzoapyrene
20–40ng S
P 2A
Indeno1,2,3-cdpyrene 4–20ng
S 2B
Heterocycliccompounds Dibenza,jacridine
3–10ng S
2B Furan
18–37ng S
2B N-Nitrosoamines
N-Nitrosodimethylamine 2–180ng
S 2A
N-Nitrosodiethylamine ND-2.8ng
S 2A
N-Nitrosopyrrolidine 3–110ng
S 2B
4-Methylnitrosoamino- 1-pyridyl-1-butanone
80–770ng S
2B Aromaticamines
2-naphthylamine 1–334ng
S S
1 4-Aminobiphenyl
2–5.6ng S
S 1
N-heterocyclicamines AaC
25–260ng S
2B PhlP
11–23ng S
P 2A
Aldehyde Formaldehyde
70–100mg S
L 2A
Acetaldehyde 500–1,400mg
S I
2B Volatilehydrocarbons
1,3-Butadiene 20–75mg
S I
2B Benzene
20–70mg S
S 1
Miscellaneousorganiccompounds Acrylonitrile
3–15mg S
L 2A
Vinylchloride 11–15ng
S S
1 DDT
800–1,200mg S
P 2B
DDE 200–370mg
S 2B
Catechol 100–360mg
S 2B
Ethyleneoxide 7mg
S S
1 Propyleneoxide
12–100mg S
2B Inorganiccompounds
Hydrazine 24–43ng
S I
2B Arsenic
40–120mg I
S 1
Nickel ND-600ng
S S
1 Chromiumonly
hexavalent 4–70ng
S S
1 Cadmium
7–350ng S
S 1
Cobalt 0.13–0.2ng
S I
2B Lead
34–85ng S
I 2B
Polonium-210 0.03–1.0pCi
S S
1 Ssuficient;Iinadequate;Pprobable,possible;Llimited;NDnotdetected;PAHpolynucleararomatic
hydrocarbons; AaC 2-Amino-9H-pyrido[2,3-b]indole; PhlP 2-Amino-1-methyl-6-phenylimidazo [4,5-b]pyridine;IARCMonographsontheEvaluationofCarcinogenicRisks:1:Humancarcinogen;
2A:probablycarcinogenicinhumans;2B:possiblycarcinogenictohumans [23]
beregardedasmoretoxicthanmainstreamsmokebecausetheamountsofvarioussub- stancesinside-streamsmokebenzo[a]pyrene,CO,benzene,formaldehyde,hydrazine,
cadmiumetc.arehigherbyseveralmultiples.Incontrast,however,mainstreamsmoke containsapproximately1,000timesmoreparticlesthanside-streamsmoke5×10
9
vs. 1×10
5
–1×10
6
.Meanparticlesizeinmainstreamsmokeis0.2mm0.1–1.0mmandis
Agent ConcentrationNFC
Toxicity Carbonmonoxide
10–23mg Bindstohaemoglobin,inhibits
respiration,inducesatherosclerosis Ammonia
10–130mg Irritationofrespiratorytract
NitrogenoxideNOx 100–600mg
Inlammationofthelung Hydrogencyanide
400–500mg Highlyciliatoxic,inhibitslung
clearance Hydrogensulide
10–90mg Irritationofrespiratorytract
Acrolein 60–140mg
Ciliatoxic,inhibitslungclearance Methanol
100–250mg Toxicuponinhalationandingestion
Pyridine 16–40mg
Irritatesrespiratorytract Nicotine
1–3mg Inducesdependence,affectssome
endocrinefunctions Phenol
80–160mg Tumourpromoterinlaboratory
animals Catechol
200–400mg Co-carcinogeninlaboratoryanimals
Aniline 360–655mg
Formsmethaemoglobin,andthis affectsrespiration
Maleichydrazine 1.16mg
Mutagenicagent
Table 3.3
Majortoxicagentsincigarettesmokeincompletelist [23]
Condensate zone Distillate zone
embers zone about 900°C Ash
Main stream 4 mg CO
Side stream 40 mg CO
Fig. 3.1
Schematic illustrationofburning
cigarette.Mainstreamand side-streamsmokedifferin
termsofthetemperatures atwhichtheyareformed
andthecompositionof theirtoxicconstituentscf.
COcontentofacigarette
clearlysmallerthanthatinside-streamsmokeat0.5mm0.1–1.5mm,resultinginahigher proportionofparticlesinmainstreamsmokehavingatoxiceffectontissues.Furthermore,
mainstreamsmokecontains2–3×10
10
radicalsperml.Themajorityofnaphthalinesand polynuclearhydrocarbonsareformedinmainstreamandside-streamsmokeasaresultof
thecombustionprocessTable 3.2
. Thetarcontentofcigaretteshasbeenanimportantissueformorethan50years.The
tobaccoindustryhasrecognisedthattarconstituents,suchasarealsoformedbytheburn- ing of tobacco in the mainstream and side-stream smoke of a cigarette, are extremely
hazardoustohealth.Eversince1950s,thetobaccoindustryhasstriventoreducethetar yieldofcigarettescf.Fig.
3.2 .Asidefromloweringtaryields,however,thetobacco
industryisalsoconcernedwithnicotinereleaseduringthesmokingprocess,particularly sinceloweringthetaryieldalsoreducesthenicotinecontentFig.
3.3 .Asaresultof
10 1955
1960 1965
1970
Year
1975 1980
1990 0.3
0.5 0.7
0.9 1.1
1.3 1.5
Nicotine mg
1.7 1.9
2.1 2.3
2.5 2.7
2.9 3.1
12 14
16 18
20 22
24
Tar mg
26 28
Tar
Tar Nicotine mg
Nicotine Expanded blends
Tips ventilation Ventilation and
dilution perfected Filter-tips
Porous paper Reconstituted tobacco
30 32
34 36
Fig. 3.2
TarandnicotineyieldsofUScigarettesoverthepast35yearsandmeasurestoreducethe tarcontent.Cigaretteindustrydata
[23,24]
1959 Tar [mg]
Nicotine [mg10g] CO[mg]
Bap [ng] 5
10 15
20 25
35 30
[mg]
1967 1971 1977
Year
1981 1988 1991 1997
Bap [ng]
20 30
40 50
60
10
Fig. 3.3
Changesinthetar, nicotine,COand
benzo[a]pyreneBaPyields ofnon-ilterUScigarettes
between1959and1997 [23]
. Thenicotineyieldwas
calculatedwithreferenceto 10gtobacco
effortsbythetobaccoindustrylaboratories,taryieldsinUScigaretteshavebeenlowered from38mgto12mg
[23,24] .UScigarettescurrentlyhaveanicotineyieldof0.95mg.
TaryieldshavebeensimilarlyreducedinGreatBritain,butthequantitiesofnicotineinthe cigarettehavebeenkeptatahigherlevel
[25] .
Various modiications to the cigarette have been made to achieve these changes as follows:
•
Cigarettelengthhasbeenaltered
•
Moderniltershavebeenincorporatedintocigarettes [26]
•
Aromaticagentsterpenoids,pyrroles,pyrazineshavebeenintroducedintotobacco
•
Porouscitrate-treatedpaperhasbeenusedincreasingly
•
Newtobaccomixturesemployareducedtobaccovolume
•
Manufacturingtechnologyhasbeenoptimisede.g.glycerolandpropyleneglycolare moresuitablethandiethyleneglycolandsorbitoletc.formoisteningthetobacco
[27] Filterdimensionswereimportantforthepartialremovaloftoxicsubstancesfrommain-
streamcigarettesmoke:charcoaliltersreducedthecontentofciliatoxicsubstancescya- nide,formaldehyde,acrolein,acetaldehydebyupto66
[28–30] andweresuperiorto
celluloseacetateilters.Bycombiningthetwo,evenbetterresultswereachievedinterms oftheabsorptionoftoxicsubstancese.g.volatilephenolsandnitrosaminesfrommain-
streamsmoke [31–33]
. Theporosityofthepaperreducestheinhalationofvariousgaseshydrogen,NO,CO,
CO
2
,methane,ethane,ethylenebyoutwarddiffusion,whereasthediffusionofN
2
andO
2
intothetobaccoisincreased
[23] .Thereductionofnitrogenoxidesintheinhaledsmoke
lowerstheformationoftobacco-speciicN-nitrosamines [34]
. Onepreviouslyneglectedaspecthasbeenthequestionoftheoccurrenceofbacterial
endotoxinasanactivecomponentofcigarettesmoke [35]
.TheLimulusamebocytelysate LALassaywasusedtomeasurethelipopolysaccharideLPScontentofthetobaccopor-
tionandiltertipcomponentsofunsmoked“light”cigarettes,aswellasinmainstreamand side-stream smoke. In addition, blood LPS activity and plasma cytokine concentrations
TNFa,IL-6weremeasuredinsmokersandnon-smokers.BioactiveLPSwasdetectedin the“light”cigarettes,intheiriltertips,andinbothmainstreamandside-streamsmoke;no
differencesinbloodLPSlevelsweredetectedbetweensmokersandnon-smokers.Interms ofadverseeffectsonhealth,however,itisestimatedthattheLPSdosedeliveredfromsmok-
ingonepackofcigarettesdayiscomparabletothelevelofLPSexposureofcottontextile workersdustfromtextilemanufactureandthat,inaddition,LPSreleasemaybeonefactor
responsibleforthedevelopmentofchroniclungdiseaseschronicbronchitis [35]
.