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INDOOR AIR POLLUTION

Children's Health and the EnvironmentWHO Training Package for the Health Sector

World Health Organization

www.who.int/ceh

TRAINING FOR THE HEALTH SECTORTRAINING FOR THE HEALTH SECTOR[Date [Date Place Place EventEventSponsorSponsorOrganizer]Organizer]

July 2008 version

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Indoor Air Pollution Indoor Air Pollution

LEARNING OBJECTIVESLEARNING OBJECTIVESTO UNDERSTAND, RECOGNIZE AND KNOW:TO UNDERSTAND, RECOGNIZE AND KNOW:

Hazards of indoor air pollution to childrens health

Different toxicants in indoor air, according to sources, settings and activities

Characteristics and issues relating to indoor air pollution in industrialized and developing countries

How to recognize, assess and address health effects

How to prevent exposure to indoor air contaminants

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Indoor Air Pollution Indoor Air Pollution

OUTLINEOUTLINE

Scope of the problem of indoor air pollution Scope of the problem of indoor air pollution

Particulate matterParticulate matter

Carbon monoxideCarbon monoxide

SecondhandSecondhand tobacco smoketobacco smoke

PesticidesPesticides

SolventsSolvents

Volatile organic compoundsVolatile organic compounds

Biological pollutantsBiological pollutants

-- MitesMites

-- AllergensAllergens

-- MouldsMoulds

Built environmentBuilt environment

Radon Radon

AsbestosAsbestos

OccupationOccupation--related contaminantsrelated contaminants

The indoor contaminants addressed in this module include:

Particulate matter

Carbon monoxide

Secondhand tobacco smoke

Pesticides

Solvents

Volatile organic compounds

Biological pollutants

- Mites

- Allergens

- Moulds

Built environment

Radon

Asbestos

Occupation-related contaminants

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Indoor Air Pollution Indoor Air Pollution

CHILDRENCHILDRENS UNIQUE VULNERABILITYS UNIQUE VULNERABILITY

Inhale more pollutants per kilogram of body weight than Inhale more pollutants per kilogram of body weight than

do adultsdo adults

Because airways are narrower, irritation can result in Because airways are narrower, irritation can result in

proportionately greater airway obstructionproportionately greater airway obstruction

WHO

Infants and young children have a higher resting metabolic rate and rate of oxygen

consumption per unit body weight than adults because they have a larger surface area per

unit body weight and because they are growing rapidly. Therefore, their exposure to any air

pollutant may be greater.

In addition to an increased need for oxygen relative to their size, children have narrower

airways than do adults. Thus, irritation caused by air pollution that would produce only a

slight response in an adult can result in potentially significant obstruction in the airways of a

young child.

Ref:

Moya J et al. Childrens behavior and physiology and how it affects exposure to

environmental contaminants. Pediatrics, 2004, 113:996.

American Academy of Pediatrics Committee on Environmental Health. Pediatric

Environmental Health, 2nd ed. Etzel RA, Ed. Elk Grove Village, IL: American Academy of

Pediatrics, 2003.

Children's Health and the Environment A global perspective. A resource guide for the

health sector, WHO, 2005.

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Indoor Air Pollution Indoor Air Pollution

SMALLER AIRWAYS MORE VULNERABLESMALLER AIRWAYS MORE VULNERABLE

www.vh.org/pediatric/provider/pediatrics/ElectricAirway/Diagrams/AirwayDIaneterEdema.jpg

The effect of oedema on the adult airway is much less dramatic than it is on the newborns

airway. One millimetre of oedema reduces the diameter of the adult airway by about 19%

whereas it reduces the diameter of the infant airway by 56%.

Compared to that of adults, the peripheral airway (bronchioles) is both relatively and

absolutely smaller in infancy allowing intralumenal debris to cause proportionately greater

obstruction. In addition, infants have relatively larger mucous glands, with a concomitant

increase in secretions. They also have the potential for increased oedema because their

airway mucosa is less tightly adherent. Lastly, there are fewer interalveolar pores (Kohns

pores) in the infant, producing a negative effect on collateral ventilation and increasing the

likelihood of hyperinflation or atelectasis.

The resting minute ventilation normalized for body weight in a newborn infant (400

cc/min/kg) is more than double that of an adult (150 cc/min/kg).

Ref:

Bar-on ME et al. Bronchiolitis. Prim Care, 1996, 23:805-19.

Picture:

www.vh.org/pediatric/provider/pediatrics/ElectricAirway/Diagrams/AirwayDIaneterEdema.jpg

- Copyright protected material used with permission of the authors: Drs. Michael and Donna

D'Alessandro - and the University of Iowa's Virtual Hospital, www.vh.org

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Indoor Air Pollution Indoor Air Pollution

DEPOSITION OF POLLUTANTS IN RESPIRATORY TRACTDEPOSITION OF POLLUTANTS IN RESPIRATORY TRACT

CDC

Respirable particles and gases affect different parts of the respiratory tree depending upon

their inherent characteristics. For gases, relative solubility is important. For particles, size is

important.

This slide shows the upper, middle and lower respiratory tract. Note that sulfur dioxide,

because it is highly water soluble, initially affects the upper airway, whereas ozone, which

has medium solubility, initially affects the middle airways, and nitrogen dioxide, which has

low solubility, initially affects the lower airways.

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Indoor Air Pollution Indoor Air Pollution

SIZE MATTERSSIZE MATTERS

Coarse particles (2.5Coarse particles (2.510 10

micrometresmicrometres) deposited in ) deposited in

the upper respiratory tract the upper respiratory tract

and large airwaysand large airways

Fine particles (< 2.5 Fine particles (< 2.5

micrometresmicrometres) may reach ) may reach

terminal bronchioles and terminal bronchioles and

alveolialveoli

Particle size is the most important factor in determining where particles are deposited in the

lung.

Compared with large particles, fine particles can remain suspended in the atmosphere for

longer periods and be transported over longer distances.

Some studies suggest that fine particles have stronger respiratory effects in children than

large particles.

This diagram shows that particles greater than 10 micrometres rarely make it past the upper

airways, whereas fine particles smaller than 2 micrometres can make it as far as the alveoli.

Ref:

World Health Organization. Air Quality Guidelines. Geneva, World Health Organization:

Department of Protection of the Human Environment, 2005.

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Indoor Air Pollution Indoor Air Pollution

RESPIRATORY DEVELOPMENT:RESPIRATORY DEVELOPMENT:CONTINUES THROUGH LINEAR GROWTHCONTINUES THROUGH LINEAR GROWTH

10 X 106 Alveoli300 X 106 Alveoli

(age 8)

Growth/structure Second-hand tobacco smoke

Particulates Ozone

Function Indoor air quality Ambient ozone

Dieter,t 2000

2 to 82 to 8

Like the nervous system, the respiratory system continues to grow and develop through

linear growth. The upper section of the diagram depicts the different developmental phases

of the lungs corresponding to the age of the embryo/fetus. It may be seen that at birth, a

baby has about 10 million alveoli, but at age 8 years, the lungs have grown and the number

of alveoli has reached 300 million. Exposures during this growth period are known to have

adverse consequences on both structure (growth of the lungs, as illustrated in the diagram)

and function (which is affected by indoor air quality and ozone exposure).

Figure: Dietert RR et al. Workshop to identify critical windows of exposure for children's

health: immune and respiratory systems work group summary. Environmental Health

Perspectives, 2000, 108:483-90. Reproduced with permission from Environmental Health

Perspectives

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Indoor Air Pollution Indoor Air Pollution

0 20000 40000 60000 80000 100000 120000 140000 160000

Underweight

Unsafe water, sanitation and hygiene

Indoor smoke from solid fuels

Zinc deficiency

Vitamin A deficiency

Iron deficiency

Unsafe sex

Lead exposure

Climate change

Unsafe health care injections

Ambient air pollution

Alcohol

Illicit drugs

Attributable burden of disease 04 years

1000 DALY

World Health Report 2002

In analyses by the World Health Organization (WHO) in 2002, the indoor smoke from solid

fuels accounted for the third highest disability-adjusted life years (DALYs) for children 0 to 4

years of age.

The DALY is a health measure that incorporates loss of quality of life as well as loss of years

of life. One DALY is the loss of one healthy life year.

Ref:

World Health Report 2002 (www.who.int/whr/2002/en/).

Picture: World Health Report 2002

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Indoor Air Pollution Indoor Air Polluti

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