Indoor Air Pollution

Question 1

What is indoor air pollution?

Answer 1

Indoor Air Pollution(IAP) refers to air pollution in an indoor
environment such as buildings, cars, train, etc. Not only airborne
compounds and particles are of interest but constituents of
settled dust as well.

Question 2

What are the sources of indoor air pollution?

Answer 2

Man-made sources - fossil fuel burning, environmental tobacco
smoke(ETS), vehicle emissions, outdoor industrial sources,
household cleaning products.
– Biological sources - dampness/excessive moisture,
bacteria, viruses, animal dander, insects and mould.
Other pollutants occur naturally in nature such as
radon gas(radioactive)

Question 3

How is exposure to indoor air pollution assessed and managed or mitigated?

Answer 3

1) Assessment of biological markers provides a
measurement of air pollutant concentrations in an
individual’s body (used mostly in occupational settings).
– Sampling & analysis of urine or blood for pollutant
derivatives

Personal exposure monitoring provides a
measurement of air pollutant concentrations in an
individual’s immediate environment.
– personal exposure monitoring can identify particular
behaviors and lifestyle activities that influence
personal exposure to air pollution.

3) Environmental exposure monitoring provides levels
of pollutants in the environment of concern – (most
used method because of its convenience)
– Walkthrough assessment – checklist & questionnaire
(observations and queries used)
– Collect air or dust samples from the area of interest

Question 4

What are the health effects resulting from exposure to indoor air pollution?

Answer 4

Sometimes a single type of bioaerosol can produce
multiple effects, e.g., the mould Aspergillis fumigatus
(common in hospitals) can cause:
– asthma and rhinitis (most common allergen among fungi)
– allergic alveolitis (among farmers)
– allergic bronchopulmonary aspergillosis (growth in airways)
– Aspergilloma (growth in lungs)
– toxic effects in animals only (cytotoxic, neurotoxic,
nephrotoxic, impaired immune system)
– 1,3 B-glucan (irritative)
– fungal sinusitis
With effects of climate change (heat waves, floods,
etc.) - contamination of indoors with biological
agents is likely to increase.

Question 5

Pathogens or infectious agents.

Answer 5

is a biological agent that causes disease or illness to its host.

Question 6

Mycotoxins.

Answer 6

Are toxic chemicals produced by fungi, e.g. penicillin used as antibiotic

Question 7

Bioaerosols.

Answer 7

Aerosols or particulate matter from living organisms (microbial, plant or animal)

Question 8

The world of particles, Consider the sneeze.

Answer 8

During a sneeze, millions of tiny droplets of water and mucous
are expelled at about 100 m/s
• Droplets about 10-100 µm in diameter are formed but dry rapidly to
droplet nuclei of 1-4 µm
• These droplet nuclei are the means of transmission of several
diseases of humans
• Provided the density is the same - the fall will be:
– 100 µm take about 2s to fall a height of 1m
– 10 µm takes about 3min
– 1 µm takes about 4hr
– 0.1 µm takes about 6 days

Question 9

Particle deposition in the respiratory system

Answer 9

Nose 
Mouth
Esophagus 
Trachea 
Bronchus, and Bronciole
Alveoli

Question 10

Major sources of man-made pollution are:

Answer 10

– cooking and heating fuels (wood, paraffin, coal, etc.)
– environmental tobacco smoke (ETS) &
– others sources such as outdoor–vehicle emissions, etc.

Question 11

Emissions from the burning fuel, ETS, and other activities

result in these compounds

Answer 11

\:
– carbon monoxide (CO)
– carbon dioxide (CO2)
– sulfur oxides(SOx)
– nitrogen oxides(NOx)
– particulate matter (PM)
– particulate matter (soot)
– volatile organic compounds(VOCs)
– polycyclic aromatic hydrocarbons
(PAH

Question 12

Carbon monoxide

Answer 12

Carbon Monoxide binds with Hb - COHb
– low birth weight
– increase in perinatal deaths
– asphyxiation [lack of oxygen in the brain]

Question 13

Nitrogen Dioxide (NO2)

Answer 13

• Acute exposure cause an increase in bronchial reactivity
– exacerbation of asthma and/or reduce lung function
• Long term exposure increases bacterial and viral
infections
– respiratory infections

Question 14

Sulphur Dioxide (SO2)

Answer 14

• Acute exposure increase bronchial reactivity
– exacerbation of asthma
• Long term exposure is difficult to dissociate with particulate
effects
– lung & heart disorders

Question 15

Particulate Matter – PM (soot)

Answer 15

• Long term exposure cause biochemical and pathological changes
- heart and lungs
– lung and heart disorders
– genetic changes

Question 16

Polycyclic Aromatic Hydrocarbons(PAHs)

Answer 16

• These compounds when metabolized can cause cell damage

– human cancer risk

Question 17

Biological contaminants

Answer 17

Common indoor biologicals are:
Fungi (mould) – over 6000 genera, 100,000 species.
Pollen - from grasses, trees, weeds, crops – most common allergen.
Yeasts – unicellular fungi. Pathogenic species include those associated with
bird droppings
Bacteria – Staphylococcus, Pseudomonas. Actinomycetes, Bacillus,
Legionella, pathogens (TB)

Question 18

Health Effects of Biological

Contaminants

Answer 18

1. Infectious - pathogens invade human tissues
2. Allergic - specific activation of the immune system causes
   disease
3. Toxic - where biologically produced chemical toxins cause
   direct toxic effects

Question 19

Infectious Pathogens

Answer 19

• Human source: influenza, the common cold, rubella, chicken
pox, tuberculosis, staphylococcus aureus.
• Animal source: Anthrax, Q fever, brucellosis.
• Environmental source: bacterial pneumonia (Legionnaire’s
and Pontiac fever), fungal infections, rarely amoebae
infections.
– Some bacteria and viruses thrive in buildings and circulate
through ventilation systems and cause a serious and sometimes
lethal infection - Legionnaire’s disease and Pontiac fever

Question 20

Allergic Responses

Answer 20

• Often connected with animal dander (cats, dogs), house dust mites
(microscopic animals living in household dust), and pollen.
• Common signs and symptoms include watery eyes, runny nose
and sneezing, nasal congestion, itching, coughing, wheezing and
difficulty breathing, headache, fatigue.
• Allergic reactions can range from mildly uncomfortable
to life-threatening, as in a severe asthma attack.
• Many airborne allergens not identified.

Question 21

Toxic Reactions

Answer 21

• mycotoxins may be found in both living & dead spores of fungi and
in cell wall of certain bacteria (bacilli).
• toxins can damage a variety of organs/tissues, e.g., liver, central
nervous system, digestive tract, immune system, etc.
• exposure to dust contaminated with mycotoxins can lead to cancer
of the lung & livertoxicity.
• can also cause lethargy, headache, irritation of the eyes and
mucous membranes of the nose & throat.

Question 22

Addressing Indoor Air Pollution

Answer 22

• Source control
– identify, remove, and/or source and clean reservoirs
– repair/stop-leaks, moisture generators, etc.
• Ventilation improvements
– natural ventilation- windows, doors, wall
ventilators, etc.
– artificial ventilation - a/c, fans, extract fans, chimneys, flue
pipes etc.
• Air cleaners
– mechanical filters, ion generators & electronic air cleaners
– air conditioners