01-11-2016, 12:04 PM
1462934931-zuskin3740.pdf (Size: 81.95 KB / Downloads: 8)
Abstract
Background and Purpose: Indoor pollutants could be significant public
health risks. People in modern societies spend about 90% of their time in
indoor environment. In spite of the evidence of harm to human health, poor
indoor environments are generally hard to understand.
Materials and Methods: There are numerous indoor atmospheric pollutants.
Specifically, combustion sources, building materials, volatile organic
compounds, central heating and cooling system are described.
Results: Indoor home environments are the site of a variety of biological
and other environmental hazards. Indoor environmental quality has a significant
impact on public health and well-being. These hazards cause and
exacerbate a variety of adverse health effects in humans, ranging from acute
and chronic respiratory symptoms and diseases to cancer. We review the effects
of indoor allergen exposure and sensitization on asthma, focusing on
dust mite, fungi, indoor pollutants such as ozone, particulate matter nitrogen
dioxide, environmental tobacco smoke, sulfur dioxide, carbon monoxide
and dampness of buildings. Additionally, the effects of lead, as well as
carcinogenic effects of asbestos, radon, and smoking habits are described.
Conclusions: Preventive measures, such as identification of a source of
chemical, physical, or biological pollutants that may have deleterious health
effects, and improvement of such harmful environmental conditions should
be undertaken.
INTRODUCTION
As early as several centuries ago B.C. the famous Greek »father of medicine«
Hippocrates (460-370 B.C.) was aware of the adverse effects
of polluted air and the damage of living in damp housing.Poor indoor
environmental quality is an important health risk worldwide. People
in modern societies spend about 90% in indoor environments,
which has a significant impact on public health and well-being (1).
Numerous health risks have been identified in homes and are a public
health priority (2). Hazards in indoor environments include biological
and chemical contaminants as well as the effects of physical agents.
Main sources of indoor pollution include combustion sources (oil, gas,
kerosene, coal, wood and tobacco products), volatile organic compounds,
building materials (asbestos), carpets, house cleaning and
maintenance, personal care or hobbies, central heating and cooling system
and humidification devices, lack of ventilation, too much humidity,
water infiltration or leakage, carbon monoxide and other gases, radon
and other noxious agents
Chemical hazards include numerous chemical agents,
such as nitrogen and sulfur oxides, ozone, pesticides, formaldehyde,
infectious agents, and biological agents (microbial
organisms, mold, dust mites) (5-8).
Temperature, relative humidity, extensive cold or hot
surfaces, and draft effects also modify the effects of chemical
and biological contaminants. Some agents include
allergens, and agents such as colorless, odorless gases and
aerosolized toxins, physical stimuli such as bright lights
and loud sounds (9). Chaiearet a. recently (10) described
persons suffering from erythema and other skin changes,
conjuctive infection caused by indoor radiation pollution
due to ultraviolet C radiation from germicidal ultraviolet
lamps.
Table 1 presents some of the sources of indoor air pollutants
and their potential health effects.
Identification or recognition of the deleterious effects
of some agents are determined by evaluating the risk of
developing certain diseases or impairment. It is very important
to estimate the dose-effect relationship of a certain
agent on individual bases. Larger doses of noxious
agents may have detrimental effect on the whole body.
Such effects depend on individual sensitivity to certain
harmful agent/s. Simultaneous exposure to different environmental
agents may have cumulative noxious effects.
There are Maximal Allowable Concentrations (MAC) for
almost all environmental agents (organic and physical) to which subjects could be exposed without a risk for developing
disease.
Deleterious health effects may show up after a single
or repeated exposure to certain indoor pollution depending
on age, preexisting medical conditions and individual
sensitivity.
COMBUSTION PRODUCTS
Diverse indoor combustion sources contribute to the
quality of indoor air environment (11). Indoor combustion
products include mostly environmental tobacco smoke,
woodsmoke, carbon monoxide, nitrogen and sulfur dioxide,
soot and organics from incomplete combustion.
Combustion products – dangerous gases and particles
can be generated by different appliances such as water
heaters, unvented gas or kerosene space heaters, etc.
Among such gases, the most frequent are carbon monoxide
and nitrogen oxides.
VOLATILE, NONVOLATILE AND OTHER
NONBIOLOGICAL AGENTS
These compounds include household and office products
such as formaldehyde, pesticides, solvents, cleaning
agents, heavy metals (airborne lead, mercury vapor,
asbestos, radon).
Chemicals
The chemicals we breathe (such as perfumes, formaldehyde,
pesticides, solvents, cleaning agents, benzene,
perchloroethylene, hair sprays, household products (finishes,
rug and oven cleaners, paints, thinners, dry cleaning
fluids), some copiers and printers, glues and adhesives,
markers and photo solutions are among some of
the common products that may emit organiccompounds.
Volatile organic compounds are among major pollutants
of indoor air which have a significant impact on indoor
air quality and thus affect human health (12).
Multiple chemical sensitivity (MCS) is a syndrome in
which multiple symptoms are caused by extremely low
concentrations of environmental chemicals (13). Common
symptoms include irritation of the eye, nose and
throat, hoarseness of voice, headache, fatigue, difficulty
in concentrating, depressed mood, memory loss, weakness,
dizziness, heat intolerance and arthralgia (14). Symptoms
are precipitated by a wide array of common environmental
agents.
Asbestos
Indoor exposures to this agent are generally quite low,
they may be higher than outdoor concentrations, and can
be substantial following remodeling, pesticide application,
or other product use. Asbestos exposure only exists
if the asbestos-containing material is distributed and microscopic
asbestos fibers are released into the air (15).
Breathed-in asbestos fibers in the lungs can increase
the risk of lung cancer and mesothelioma. Smoking drastically
increases the risk of lung cancer from asbestos exposure.
Average indoor asbestos levels are extremely low
so that the related health risk is assumed to be low from
the mere presence of asbestos-containing material.
Lead
Everyone is exposed to trace amounts of lead through
inhalation of lead vapors since many consumer products
and paints contain lead.
Lead toxicity causes hematological, gastrointestinal
and neurological dysfunction. Anemia is common and
damage to the nervous system may cause impaired mental
function. Other symptoms are appetite loss, abdominal
pain, constipation, fatigue, sleeplessness, irritability
and headache. Severe or prolonged exposure may also
cause chronic nephropathy, hypertension and reproductive
impairment(16). Lead inhibits some enzymes, alters
cellular calcium metabolism, stimulates synthesis of
binding proteins in kidney, brain and bone, and slows
down nerve conduction.
Radon
Radon in air is ubiquitous. Radon gas, a naturally occurring
radioactive soil gas, can infiltrate the air in the
house. Radon enters homes through cracks in the foundation,
floor drains, sump pumps and other openings
When radon is inhaled, its radioactive breakdown
products deliver a radioactive assault to the lungs, which
increases the risk of lung cancer. For smokers, the risk of
lung cancer is significant due to the synergistic effects of
radon and smoking. However, radon may also be the
leading cause of lung cancer among nonsmokers. Radon
is responsible for about 21,000 lung cancer deaths every
year (18).
BIOLOGICAL ORGANISMS AND OTHER
ORGANIC POLLUTANTS
Biological organisms include bacteria, molds, fungi,
mildew, pollen, dust mites and other insects, arthropod
parts, animal dander (tiny scales from hair, feathers or
skin), animal saliva, infectious agents (bacteria and viruses),
mycotoxins and pollen.
Increased exposure to indoor allergens and selected
outdoor allergens such as grass pollen and molds, particularly
house-dust, cockroaches, animal allergens as well
as smoking are important risk for developing of respiratory
diseases, particularly asthma and allergic sensitization
(19).
Bacteria, fungi and molds can flourish in improperly
maintained air ducts, air conditioners, humidifiers,
dehumidifiers, air-cleaning filters, carpets and in improperly
ventilated places where moisture is likely to collect,
such as bathrooms, kitchens, laundry rooms and
basements.
Adverse health effect associated with certain fungi is
small molecular toxin (mycotoxin) produced by these
fungi. The most frequent disease related to biological
factors include legionaire’s disease, allergic reactions, hypersensitivity
pneumonitis, humidifier fever and tuberculosis.
Molds
Molds are the major pollutant in the indoor environment.
About 5% of individuals are predicted to have
some allergic airway symptoms from molds over life
time. Indoor mold can usually be seen or smelled. Mold
can be found behind painted walls, carpets, cabinets,
walls, ceilings, and even in cleanly-maintained kitchen
material and furnishings which provide ample nutrition
for many species of molds.
Health problems that arise from exposure to mold include
allergic illness, irritant effects, infection and toxic
effects. For people that are sensitive to molds, symptoms
such as nasal and sinus irritation or congestion, dry
hacking cough, wheezing, skin rashes or burning, watery
or reddened eyes may occur (20). Mold can also trigger
asthma attacks in persons with asthma. Superficial fungal
infections of skin and nails are relatively common in
normal individuals. Headaches, memory problems,
nosebleeds and body aches and pains are sometimes reported
in mold complaints.
Air conditioning system
In air-conditioned buildings indoor air quality is dependent
on the efficiency of air-conditioning and humidifier
systems since these systems provide a suitable
environment for the proliferation of microorganisms.
Bioaerosols may spread in the indoor environment through
the air-conditioning system.
Humidifier fever/hypersensitivity pneumonitis is a disease
with symptoms of hypersensitivity pneumonitis related
to bacterial endotoxins, fungi and amebae found in
humidifier reservoirs, air conditioners and aquaria. Disease
is characterized by fever, headache, chills, myalgia
and malaise. It normally subsides within 24 hours without
residual effects.
Humidifier lung disease with cough fever, myalgia
and arthralgia was described as a result of inhaling endotoxin
present in the humidifier water (21). Hypersensitivity
pneumonitis due to use of portable home ultrasonic
humidifier was described by Alvarez-Fernandez et
al. (22) and Volpe et al. (23).
PREVENTION
The US Environmental Protection Agency (EPA) rates
indoor pollution among the top environmental health
risks. For this reason, it is important to assess the air
quality of workplaces and homes. The indoor air levels of
many pollutants may be 2-10 times higher than outdoor
levels. These levels of indoor air pollutants are of particular
concern because most people spend as much as 90%
of their time indoor.
Preventive measures should be directed toward identifying
indoor air sources that may be possible causes and
reduce exposure to biological contaminants with immediate
health benefits. The measures to keep healthy indoor
air we breathe include: introduction and distribution of
adequate ventilation air; control of airborne contaminants;
maintenance of acceptable temperature and relative
humidity. This also includes a special attention to
moisture control.
Many types of adjustments could improve environmental
conditions. For instance, open windows improve
air flow, minimizing the temperature decreases the growth
of molds, and restricted use of colognes or perfumed
soaps, shampoos, deodorants, and air fresheners can help
control the indoor environment.