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Air pol lut ion poses heal th problems throughout the wor ld. Firs t we-provide a general overview of the health hazards associated with air pollution, emphasizing thetypes of medical disorders that a irborne substances can generate . Air pol lut ion ismost often associated with factories and with outdoor air . But , as discussed next , . the.greates t source of harmful a ir pol lut ion is c igardt te smoking. Moreover , as we thenshow, the heal th hazards from pol luted air ins ide our homes are of ten worse than

th at f ro m o u t d o o r air , e ve n in a n i nd u st ri al city't > (t. '

A. A ir Po l lu t ion an d Heal th

Air pollution mainly damages the lungs and -airways, although injury to other organs canhappen as well. In this section, we describethe majo r effects of the most comm on pol lutants in the air we breathe. Accidental releaseof airborne chemicals, such as chlorine andammonia, also cause problems, but becausethese accidents are rare, they are not includedin this chapter but left to the appropriate entry headings in Part II. Indoor air pollutantscan be of even greater concern than outdoor

pollutants, in part because a large proportion !of our time is spent indoors. In doo r pollution

is especially significant in the homes of srrldk-,

ers and where radon concentrations are high, i

This is discussed more in Sectio n C of th is 1,chapter (Ind oor Air Pollution). 1

We have divided the health effects o f ;

air pollution into four groups: short-termor acute respiratory effects, long-term orchronic respiratory effects, lung cancer, and |

nonrespiratory effects. Damage is said to be !acute if it happens suddenly and id relatively short-lived, a few minutes to a few days. An jasthmatic attack, for example,' is ah acute ef- ;feet. Chr on ic effects persist over; extended. !periods of time, generally years. Permanent >respiratory loss from a decreased rite of luhg !growth in children and obstructive pulmo- >nary disease (discussed later) are examples of jchron ic effects. '

A cu te Resp iratory Effec ts

Four acute respiratory effects of air pollutionare well established: (1) asthmatic attacks,(2) hyperreactive airways, (3) respiratory infections, and (4) reversible changes in lungfunctions. A st hm a is a condition affectingabout 10 million Americans, in which the airways suddenly narrow, obstructing the flowof air .through the lungs. T he narrow ing iscaused by spasn.o of the small muscles that xencircle the airways and by the release ofthick, excessive mucus that plugs them. An'

attack can be triggered by an allergic reactionto i foreign substance (either breathed orswalidwed) and by a variety of other stimuli,

sucfi ki respiratory infections, exercise, coldairland emotional stress. Air pollution canbring on asthmatic attacks. In Los Angeles,attiibks have been associated with ozone andpart icu late pollution, and in areas surround

ing power plants and smelters, sul fur dioxideaildfjSulfate particulates cause reactions. It is

not kno wn whether air pollution can actuallycij ise Asthma or whet her it onl y triggers asthmaticattacks.

'.Another 20 million Americans have whatare Jjcalled hyperreactive airways, which areairways that constrict much m ore readily thanaverage in response to foreign matter. Unlikearthina, som e; constriction o f the airways is

a ;ridrmal defense mechanism to prevent inhaling noxious substances. In persons with

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hyperreactive airways, however, the airways 1respond to levels that do not bother mostpeople. The symptoms are similar to asthma: -

shortness of breath, coughing, and wheezing.Sulfur dioxide, particulates, ozone, and nitro ge n oxides are kno wn to stimulate airway Ireactivity.

The incidence of respiratory infections, \particularly in children, is increased by air jpollution. Upper respiratory infections, suchas colds, influenza, and Sore throats, are associated with sulfates, sulfur dioxide, and iparticulates in outdoor ait. Nitrogen dioxide

released indoors by gas cooking stoves is as

sociated with more frequent colds in childrenunder the age of 10 compared with childrenwho live in homes equipped with electricranges. Animal studies show chat concentrations of ozone and nitrogen dioxide typicalof peak pollution episodes lower the resistance to bacterial infections, such as pneumonia and acute bronchitis. Air pollutantsboch disable the clearance mechanisms thatremove viruses and bacteria from the respiratory tract and incapacitate the cells that fight

the infections.Short-term, reversible changes in lung

function are also caused by air pollutants. F orexample, th maximum amount ofi air that

can. be inhaled cf exhaled iii one second is re

duced in both children and healthy adults

when exposed to elevated pollutant Toricri-trations, but this returns to normal when exposure ceases. Whether such change# iridic'atethat long -term damage ii? Being done notkn ow n at the present time.'' -I

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the lungs with old age and against the onSctof obstructive pulmonary disease, which occurs more commonly at older ages.

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Lung Cancer

Cancer of the lung is the leading fatal canceramong both men and women, responsible forover one-fourth of all cancer deaths. Smoking is the major cause of lung cancer. Air pollution causes some fraction of lung cancers,but exactly how much is in dispute. Some experts contend that air pollution causes onlya few percent of all cases, while others argue that its 20% or more. It is clear thatcarcinogenic compounds are present in indo or air and polluted ! out do or urban air.Chemical analyses of air show the presenceof cancer-causing by-products of burningsuch as benzo-[

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from cancer to brain disorders. With the not able exception of lead, air quality hasjnot improved significantly in the last ten years, and

in some instances it has gotten worse! Thewidespread health effects of many pollutants,such as lead, asbestos, and radon, have beengenerally recognized only within the last tenyears, and new products and substances areconsta ntly being introduced. Air quality mustremain a top priority, both at home and i:nthe political arena, if the quality of life is notto suffer.

B. Sm ok ing and Heal th

Cigarette smoking is the single most preventable major cause of death in our society.More than one in every six deaths in theUnited States can be attributed to mokirig,over 390,000 deaths anniially. At every age,proportionately more smokers die each yearthan do nonsmokers. Tobacco contributes to30% of all cancer deaths yearly, including85% of all lung cancer deaths. Smokers over

all have a 70% greater coronary heart diseasedeath rate the leading cause of death com pared to nonsmokers. An additional 10 mil

lion Americans suffer inctedsed rates of various debilitating diseases carised by smoking,

including bronchitis, em physem a, And ath ero -sclerosis. Inhaling other peoples smoke, t>rpassive sm ok ing , is now'firriplicated kb disease (particularly lung caftber) arhong non-smokers.

Who Smokes and Who Doesnt:

Trends in Smoking Habits

The fraction of American adults who smokedin 1987 was 29 % , down fio n i 40 6/o In 1965.

Men smokers st i l l outnumber womeii smokers, but the differential has been shrinking,

and among high school seniors, more girlssmoke than do boys. The greatest increase in

smoking has been among women aged 20 ter

34. The progress made in reducing the smoking rate has been largely dtie to smokers quit-

5 0 ALI. ABOUT TOXICS

; ting rather than to fewer people taking up the; habit. Nea rly h alf of all living adults who

everyrioked have quit. But the most recent

; information about smoking among teenage: boy s shows that primary prevention (never

smoking) is beginning to play a part in reduc-ing-the smoking rate.

Among blacks, blue-collar workers, andless educated people the smoking rate ishigher than in the population as a whole.Level of education is more closely related tosmoking than any other factor. The higherthe level of educa tion, the less likely some oneis to be a smoker.

Snicking begins primarily during child-hood ' and adolescence. One -four th o f highschool seniors who have ever smoked hadtheir first cigarette by sixth grade, one-half

: by eighth grade. F or those who begin smo k-: ing befo re age 20, the youn ger they begin, the; mor e-li kely they are. to con tinu e and the moreI likely; they .are to smqlce heavily. Th ese facts;indicate the imjbortancir of starting smoking' education campaigns at the earliest possible; ages. ;

ft

Diseases Caused By Smok ing

- i -''I1- : . ,Lun g Tan cer is the disease most often iden

tified jfwith smo kin g. In 19 85, sm okin g accounted for 87% of all lung cancer deaths.Atnorig women, lung cancer recently over-fookiBrit cancer as the leading fatal cancer, direct result oF the increase in female smok- 'Itk' 1 1' 'ing over' th past three decades.

IC ji & b diseases kno wn to be caused bysmo kin g . include coro nary heart disease,

stroky arid peripheral vascular disease (asmiriyjjbaies of cardiovascular disease as lungcancei| afe caiisd by sm okin g); can cers of

th lry fN , m ou th, and esophagus; chronicobstructive pulrhohary disease (C O PD ); fetalgrowfftVretafdation; and low birth weight ba-

bisi-CSgartte smoking is now considered tob e ('jijfbable use of unsuccessful preg-

nahdy| Increased infant mortality, and peptic

ulcer .disease; to be a con tribut ing fa ctor incancer! Of the bladder, pancreas, and kidney;

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and to be associated with cancer of the stomach. Tobacco smoke also interacts with various workplace substances and with alcohol toincrease the risk of cancer.

There are over 4000 compounds present intobacco smoke, many of which have beenproven to be toxic or to cause cancer and mutations. A total of 43 carcinogens have beenidentified, including several nitrosamines,benzo[tf]pyrene, cadium, nickel, and zinc.Carbon monoxide, nitrogen oxides, andparticulate matter are some of the othertoxic substances present.

Passive Smoking and Involuntary Expos ure

Breathing the smoky air produced whenother people smoke tobacco is called passivesmoking. Practically all of th substances inhaled by smokers are present in the smokedrifting off the end of a burning cigarfetteor exhaled by the person smoking. Althoughconcentrations of toxics are lower becaus ofthe dilution in the surrou ndin g air, health: ef

fects from this smoke are now established.The EP A has recently classified passive smkeas a class A carcino gn (see Ch apte r 3, Sectio nB). Lung cancer in healthy nonsmbkers is .the

most serious outcome and has been demonstrated in families of s mo ke rs. ; An incrs^ in'respiratory infections and symptoms among

children of smokers, increased syfnptomS ofallergies, chronic lng conditions! and chestpains have all been reported, as well as head

aches, nausea, and irritation of the eyes dndnose.

Involuntary exposure to substances in tobacco smoke occurS to the developing embryos of pregn ant w om en whoj smoke n

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rial because of its heat-resistant properties,can shed asbestos fibers into the indoor air ifthe material is not properly sealed. In offices,some copy machines and computer printersarc a source of toxic organic substances such

as toluene. Indeed, the air in many modernoffice buildings is particularly polluted because of the combination of Office equipment, synthetic carpets, and poo r ventilatiort.The phrase sick building syndrqme has beencoined to describe homes and work placeswhere headaches and eye irrittion are common as a result of poor indoor air quality. Inindustry, there re Occupational Safety an d Health Administration (OSHA) regulationsto protect workers against the more blatant

examples of indoor air pollution generated inmanufacturing. In principle, OSHA has theauth orit y to pr ote ct office. ..workers againstsick building syndrome, but the complex nature of the pollution in sick buildings and theambiguous nature Ojf it health effects has resulted in very little regulatory action to date.

A third source cjf indoor air pollution istoxic gases leaking1upward into the livingarea of a home from the soil beneath thehouse. This is the most serious of the sources

in the United States, for this is the way theradioactive gas radon enters. Recent evidencesuggests that toxic gases can prbably enterhouses located hear chemical waste dumpsthis way as well, a ltho ugh the ixtent o f th 'threat is not really kilown. ' |

Many commercial'products such.aS furj-niture polishes, glus cleaning agents, cos

metics , deodor izers , pesti cides , andi. solventsused in the home contrib ute to the toxicitj^ 1

of indoor air. (See the Cross-Refettices at

the beginning of the book for Spdifi t b X r jics associated with tfiese varioui ptodcts.|)Moreover, dry-cleaned clothes brought into '

the home are a source of tetrachloroetkyl--ene. These consumer products are the foUrth >source of indo or air pollu tion. ! j

The fifth sourp is tobacco smoking. Not

only is it a serious indoor air pollutant in its

own right, but as was discussed in Section Bof this chapter, yo u increase the risk of illness

from other toxics such as those just discussedif you smoke or live with a smoker.

Reduct ion of Ind oor A i r Pol lut ion

The indoor air pollution from all five sourcescan be reduced by increasing the ventilationirf-the home. Unf ortun ately , this strategy canbfe costly, for in cold weather increased ventilation means either a chillier home or higherhbating bills. Also, the higher heating billsare a symptom of a host of other environ-hiental problems such as greenhouslng warming, acid rain (see Chapter 11, Sections A andC). Indeed, much of the earliest interest in indoor air pollution stemmed from concern that

plugging the leaks in houses to save energywould seal in gaseous pollutants as well as

wUrm air.1Fortunately, there are other and better

wTyS to reduce indoor air pollution levelsthan to have excessive air infiltration and consequent energy waste. Cooking stoves can beVented with an exhaust fan, which increasesventilation right at the source of pollutionwhere it s needed most. Alternatively, electricStpVes can be used, although this means

higher outdoor pollution levels if the electricity is produced by burning fossil fuel,ii jdbb r pollu tion from space^ heating can be

jf eiUced, i f : no t co mpl et el y eliminated, by-tiding properly designed, efficient furnaces orwkod stoveS. Pollution from synthetic ma-tcitiais can be reduced by avoiding their use

tke home, provided they can be recog-

rilzed, or by airing any suspiciously smellingjf lw ' items stick as plastic tablec lo thes Until the;.niell oes away. N ew pieces of furniture,

^p'lkrcicularly Sofas and easy chairs stuffed with.TdlrtV'are o ften a m uch grea ter source o f indoor air pollution than used furniture is. The

fei so n is that by the time a'foam-stuffed cush-ioh is several years old, it will have emitted

.dihch of its formaldehyde. Reduction of in--ddor air pollution can thus be added to the

ifilhy other reasons for recycling and pro

longing the jife of consumer items (see Chapter 16, Section D). Finally, sealants ban be

' "f-sT /S TOXICS,IN AIR 53i i f - f

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used to coat some building materials to prevent release of substances such as formaldehyde or asbestos, and Indoor radon levelscan be redue'ed by a variety of ways discussed

under radon m Part II.Recent studies by the National Aeronau

tics and Space Administration (NASA) indicate that there may be another way to atleast partially reduce indoor pollution levels.NASA scientists have shown that commonhouse plants absorb into their leaves certain polluting gases such as formaldehyde,benzene, and carbon monoxide (New YorkTimes, July 26, 1988). It appears from thesestudies that some plants are better able to do

this than others. Philodendrons are particularly effective at removing these gases. Other

tilated homes, the results suggest that thesehouse' plants may be useful as well as ornamental;' Bu t even after all the strategies just de

scribed have been tried, the problem of indoor air pollution will still remain in certainsituations. Some houses contain constructionmaterials that are big sources of pollutionsuch ai asbestos which cannot be removedexcept at enormous cost. Other houses maybe located sufficiently near toxic waste dumpsso chat mo s oluti on sho rt o f cleaning up thedump is possible.! People concerned that they may have aseriousriridoor air pollution problem in their

homC.dr work place should call the appropriate, hotline number listed under the head-

plants show ing this ability are spider plants ! ing Nat iona l H otlin es (at the back of the(for removing carbon monoxide), aloe veras(for formaldehyde), and gerbera daisies andchrysanthemums (for benzene). While thetests were carried out under conditions resembling airtight spacecrafts rather than ven-

book) to obtain information on the seriousness of their sittiacion. If persistent headaches, y irritation, or general malaise seem'fo b associated with time spent indoors athomb' r w o r k , such concern is warranted.

Further Reading

AmdUR, M a r y O . 1986. Air Pollutants. Ih (Sasatett and D oulls Toxicology: The BasicScience o f Poisons. Edited by Klaass^n, Curtis D.> Amdur, Mary O., and Doull, John.3d edition. New York: Macmillan. t y, i Y y

Eriksen, M. P., LeMaISTRE, C.'A , and Hewei.L, G. R. 1988. Health Hazards ofPassive Smoking. Annual view 'of Publia, f lt h 9:47-70.

M c G i n n i s, J . M . , Sh OPLAND, Dy hd|BkWN, C. 1987. Tobacco and Health:Trends in Smoking arid SmokeleYTobccoCohsurnptnual Revikv of~Public'Hedlih8:44

National Research Council. 1985. Epiderhiok_of Sciences^ Washington, D. C. i NdtiohaliAcdmy Press.

N e r o , A. V. 1988. Controlling Indoor Airf ollut ibn. Scientific American 258(5):42-48.TURIEL, I. 1985. Indoor Air Quality cnd'Humari Health, Stanford, CA: Stanford Uni

versity Prs. ? ;j ' ; ; .; h ' I

U.S. Department of Health,and Hmn^ertcesj. 1989.' The Surgeon Generals 1989Report omReducing tHd..Health'','Gbn^tjeHcs:.of Smoking: 2-5 Years of Progress.MMWR Supplement. Morb idity n d MVtliy. Weekly Report, volume 38, number

Consumption in the United States. An

gy and Air Pollution. National Academy

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5 4 Al l. AOUTTOXICS