Indoor Air Pollution

Chapter 12, Sections 5 & 6: Types, Sources, & Effects

ObjectiveStarting new unit: Risk & Toxicology

Identify types and sources of indoor air pollution.

Explain how indoor air pollutants affect human health.

Describe ways to reduce indoor air pollution.

Read the passage…

Why is indoor air quality important?

Levels of common pollutants are generally higher indoors

70 to 90% of time spent indoors home, work, school, cars

Many significant pollution sources in the home gas cookers, paints, glues

Personal exposure to many common pollutants is driven by indoor exposure... May lead to cancer & other ailments.

Especially important for susceptible groups: sick, old, very young, pregnant women, smokers, people

with respiratory/heart problems, factory workers

Exposure Time spent in various environments in US

and less-developed countries:

Respiratory System Defense:

Nose hairs Mucus Sneezing/coughing Cilia (line upper respiratory tract)

Broken down by smoking, causing Lung cancer Asthma Chronic bronchitis Emphysema

Humans Die from Pollution Annually, U.S. estimates 65,000-200,000

premature deaths from outdoor pollution Indoor pollution included: 150,000-350,000

premature deaths Worldwide: 2.7 million premature deaths Millions more face illness

House of Commons Select Committee Enquiry on Indoor Air Pollution (1991)

“[There is] evidence that 3 million people have asthma in the UK… and this is increasing by 5% per annum.”

“Overall there appears to be a worryingly large number of health problems which could be connected with indoor pollution and which affect very large numbers of the population.”

[The Committee recommends that the Government] “develop guidelines and codes of practice for indoor air quality in buildings which specifically identify exposure limits for an extended list of pollutants…”

Top Dangerous Pollutants According to the EPA, 3 most dangerous

indoor air pollutants: Cigarette smoke Formaldehyde (colorless, extremely irritating gas;

used to manufacture many household materials) Radioactive Radon-222 Gas

Additionally: Asbestos Burning candles indoors Tiny fibers of fiberglass (potentially potent

carcinogen)

Sources of Indoor Air Pollutants

Building materials Furniture Furnishings and

fabrics Glues Cleaning products Combustion applian

ces (cookers and heaters)

Other consumer products

Open fires Tobacco smoking Cooking House dust mites,

bacteria and moulds Outdoor air

Sick Building Syndrome A persistent set of symptoms in >20%

population Headaches Fatigue Reduced Mentation Irritability Eye/nose/throat irritation

Cause(s) not known or recognizable Complaints/Symptoms relieved after

exiting building

Dry Skin Nasal Congestion Difficulty Breathing Nose Bleeds Nausea

Building Related Illness Clinically recognized disease (different from “sick building”) Exposure to indoor air pollutants Recognizable Causes

Pontiac Fever – Legionella spp. Legionnaire's Disease Hypersensitivity Pneumonitis Humidifier Fever Asthma Allergy Respiratory Disease Chronic Obstructive Pulmonary Disease

Health Effects

Important Indoor Air pollutants

Nitrogen dioxide Carbon monoxide Formaldehyde Asbestos Volatile Organic Compounds (VOCs) House dust mites (and other allergens, e.g. from

pets) Environmental tobacco smoke Fine particles Radon Chlorinated organic compounds (e.g. pesticides) Asbestos and man-made mineral fibres

Health Effects

Nitrogen dioxide (criteria pollutant) Respiratory irritant Elevated risk of respiratory illness in

children, perhaps resulting from increased susceptibility to respiratory infection; inconsistent evidence for effects in adults

Concentrations in kitchens can readily exceed WHO and EPA standards

Health Effects

Carbon monoxide (criteria pollutant) An asphyxiant and toxicant Impairs perception, slows reflexes,

headaches, drowsiness Hazard of acute intoxication, mostly from

malfunctioning fuel-burning appliances and inadequate or blocked flues

Possibility of chronic effects of long-term exposure to non- lethal concentrations, particularly amongst susceptible groups

Health Effects

Formaldehyde Sensory and respiratory irritant and

sensitizer Possible increased risk of asthma and

chronic bronchitis in children at higher exposure levels

Individual differences insensory and other transient responses

Asbestos

Health Effects

Volatile Organic Compounds (VOCs) Occur in complex and variable mixtures Main health effects relate to comfort and

well-being, but benzene (and other VOCs) are carcinogenic

Concern about possible role of VOCs in the aetiology of multiple chemical sensitivity; also implicated in sick building syndrome

Health Effects

House dust mites House dust mites produce Der p1 allergen, a

potent sensitizer Good evidence of increased risk of

sensitization with increasing allergen exposure, but this does not necessarily lead to asthma

Small reductions in exposure will not necessarily lead to reduced incidence and/or symptoms

Indoor humidity is important

Health Effects

Fungi and bacteria Dampness and mould-growth linked to self-

reported respiratory conditions, but little convincing evidence for association between measured airborne fungi and respiratory disease

Insufficient data to relate exposure to (non-pathogenic) bacteria to health effects in the indoor environment

Health Effects

Environmental tobacco smoke (ETS)

Sudden infant death syndrome

Lower respiratory tract illness

Middle ear disease Asthma 12 million children

exposed to secondhand smoke in homes

Health Effects

Fine particles (criteria pollutant) Consistent evidence that exposure to small

airborne particles (e.g. PM10) in ambient air can impact on human health; mechanisms uncertain

Chronic Obstructive Pulmonary Disease and Cardiovascular Disease patients and asthmatics probably at extra risk

Relative importance of indoor sources is unknown

Airborne Particulates Examination Take a particulate strip home to place next to your

bed. Compare with school in 3 days. With your group of 3:

Choose an area in the school Label your particulate strip Place your particulate strip Take a picture of your filled out, placed particulate strip

Partner Roles: Scribe Installer Photographer

Predict! Which location in the school do you think will

have the poorest air quality? Do you think the particulate strip next to your

bed will be the same, better, or worse?

Health EffectsRadon Naturally formed from the decay of uranium

55% of our exposure to radiation comes from radon

Colorless, tasteless, odorless gas Found in nearly all soils (levels vary) Seeps upward through soil and quickly dispersesto harmless levels outdoors BUT, indoors…

Radon: How it Enters Buildings

1. Cracks in solid floors2. Construction joints3. Cracks in walls4. Gaps in suspended

floors5. Gaps around service

pipes6. Cavities inside walls7. The water supply

http://www.epa.gov/iaq/radon/pubs/citguide.html#howdoes

Radon Risk: Non-SmokerRadon Level

(pCI/L)If 1000 people who did not smoke were

exposed to this level over a lifetime.. About X would get lung cancer

This risk of cancer from radon exposure compares

to …What to do:

20 8 Being killed in a violent crime

Fix your home

10 4 Fix your home

8 3 10x risk of dying in a plane crash

Fix your home

4 2 Risk of drowning Fix your home

2 <1 Risk of dying in a home fire

Fix your home

1.3 <1 Average indoor radon level Fix your home

.4 <1 Average indoor radon level Fix your home

If you are a former smoker, your risk may be higher

Radon Risk: SmokerRadon Level

(pCI/L)If 1000 people who smoke were

exposed to this level over a lifetime.. About X would get lung cancer

This risk of cancer from radon exposure compares

to …

What to do:Stop smoking and

…20 135 100x risk of drowning Fix your home

10 71 100x risk of dying in a home fire

Fix your home

8 57 Fix your home

4 29 100x risk of dying in a plane crash

Fix your home

2 15 2x the risk of dying in a car crash

Fix your home

1.3 9 Average indoor radon level Fix your home

.4 3 Average indoor radon level Fix your home

If you are a former smoker, your risk may be lower

Radon: Reducing the Risks

Sealing cracks in floors and walls

Simple systems using pipes and fans

Test indoor air & compare with EPA’s acceptable levels

More information

Reducing Indoor Air Pollution

Reducing Indoor Air Pollutants Using simple stoves that burn more efficiently

(reduces deforestation) Using simple solar cookers Breathing wall

Absorbs indoor dirty air Exhales clean air

Improve ventilation

Ventilation Movement of Air Into / Out of Homes Amount of air available to dilute pollutants

important indicator of the likely contaminant concentration

Indoor air can mix with outside air by three mechanisms infiltration natural ventilation forced ventilation

VentilationInfiltration

natural air exchange that occurs between a building and its environment when the doors and windows are closed leakage through holes or openings in the building pressure induced

Due to pressure differentials inside and outside of the building

Especially important with cracks and other openings in wall

Ventilation Natural ventilation

air exchange that occurs when windows or doors are opened to increase air circulation

Forced ventilation mechanical air handling systems used to

induce air exchange using fans and blowers

Trade-offs cut infiltration to decrease heating and

cooling costs vs. indoor air quality problems

What pollutants cause these problems? Suspended particulate matter: asthma

Fine particles Ultrafine particles

Sulfur dioxide: asthma/ bronchitis Nitrogen oxides: asthma/ bronchitis Volatile organic compounds: cancer