environmental health

Introduction to Environmental Health

Dr. Nadia Aziz C.A.B.C.M.
Department of Community Medicine
Baghdad Medical College

Objectives

Define Environment & Environmental Health
Describe outdoor air pollutants
Explain the effects of air pollution
Describe methods of control of air pollution

Environment

In nature, the totality of surrounding conditions. The world around you is your environment; air, sun, ground, sky, house and woods -- whatever you live within is your environment.

Environmental Health

Definition
It refers to the theory and practice of assessing, correcting, controlling, and preventing those factors in the environment that can potentially affect adversely the health of present and future generations.


Environmental Health
Environmental health comprises those aspects of human health, including quality of life, that are determined by physical, biological, social and psychosocial factors in the environment.

Environmental Health

The atmosphere and water of this earth although extensive are not limitless world and cannot with safety be used as disposal dumps.

Environmental Health

Air, water and consequently food cannot continue to be mistreated in this way without rapidly increasing danger to a rapidly increasing population in a limited world.
The average person consumes each day 4 pounds of waters and 3.5 pounds of food.

Air Pollution

The presence of chemicals in the atmosphere in quantities and duration that are harmful to human health and the environment

Types of air pollutants

• Primary pollutants - products of natural events (like fires and volcanic eruptions) and human activities added directly to the air
• Secondary pollutants - formed by interaction of primary pollutants with each other or with normal components of the air

Air Pollutants outdoor

Individual outdoor air pollutants typically exist as part of a complex mixture of multiple pollutants.

Sources of Outdoor air pollution

Large industrial facilities.
Smaller industrial operations e.g. dry cleaner and gas stations.

Sources of Outdoor air pollution

Natural sources e.g. wildfires.

Sources of Outdoor air pollution

Transportations e.g. gasoline based transportation like highway vehicles ( major source)
Others like pesticides, smoking etc..

The effects of air pollution

1- Ecological: global warming, acid rain deposition, contamination of water and food
2- Biological: irritation, increase risk of respiratory diseases and cancers or pass into systemic circulation causing systemic disease e.g. Lead poisoning.
3- Economical: losses of animals or plants, increase sickness absenteeism and medical cost.


Air Pollutants outdoor
The 6 Criteria pollutants:
Ozone (O3)
Respiratory particulate matter( PM10, PM2.5)
Lead (Pb)
Sulfur dioxide (SO2)
Carbon monoxide (CO)
Nitrogen oxides (NOx)

Ozone (O3)

Ozone is the most pervasive outdoor air pollutant.
It is the principal component of urban smog.
Ozone and other photochemical oxidants formed in the atmosphere from a chemical reaction between volatile organic compounds and ( NOx) in the presence of heat and sunlight.

Ozone (O3)

Atmospheric movement of these precursor pollutants can affect ozone levels hundreds of miles downwind from the sources of these pollutants.

Ozone (O3)

Ozone is also formed from oxygen by the action of ultraviolet light .
Is present in low concentrations throughout the Earth's atmosphere.
It is a powerful oxidant and has many industrial applications related to oxidation.

Ozone (O3)

As a powerful oxidant ozone is a potent respiratory hazard and pollutant near ground level.
It causes damage to mucus and respiratory tissues in animals, and also tissues in plants.

Ozone (O3)

Ozone layer ; a portion of the stratosphere with a higher concentration of ozone
Is beneficial, preventing damaging ultraviolet light from reaching the Earth's surface, to the benefit of both plants and animals...

Respiratory particulate material (PM10, PM2.5)

Respiratory particulate material is of solid particles and liquid droplets.
Particulates smaller than 2.5 µm are referred to as fine particles e.g. Particles result from motor vehicles, power planet and industrial operations.


Respiratory particulate material (PM10, PM2.5)
Fine particles can remain suspended in the atmosphere for long period
Fine particles are transported over longer distances compared with coarse particles.

Respiratory particulate material (PM10, PM2.5)

Particles between 2.5-10 µm are referred to as coarse particles result from mechanical breakdown of solid matter such as rocks, soil and windblown dust.
Particles larger than 10 µm are too large to be inhaled beyond the nasal passages.

Lead (Pb)

Industrial operations such as ferrous and non ferrous smelters, battery manufacturers, and other sources of lead emissions can generate potentially harmful air emission of lead.

Lead (Pb)

Paint and soil generally are the most common sources of lead exposure in children.
In developing countries the use of leaded gasoline in motor vehicles is an important source of lead exposure.

Sulfur dioxide (SO2)

The primary source of SO2 is from the burning of coal and sulfur containing oil thus major emitters of SO2 include coal- fired power plants, smelters and paper mills.
Sulfuric acid aerosol is formed in the atmosphere from the oxidation of SO2 in the presence of moisture.

Carbon monoxide (CO) & Nitrogen dioxide (NO2)

Motor vehicle emissions contribute to outdoor levels of (CO) and (NO2).
Another important source of NOx is fuel combustion from power plants.


Toxic Air Pollutant
Also known as air toxics or hazardous air pollutants, that are known or suspected to cause cancer or other serious health effect, including:
• volatile organic compounds(VOCs)
• heavy metals
• solvents
• combustion by- products(such as dioxin)

Toxic Air Pollutant

Volatile organic compounds (VOCs): are Hydrocarbon compounds that have low boiling points, usually less than 100ºC, and therefore evaporate readily. Some are gases at room temperature. Propane, benzene, and other components of gasoline are all volatile organic compounds.

Toxic Air Pollutant

Some toxic air pollutants, such as benzene, 1,3- butadiene & diesel exhaust, are emitted primarily from mobile sources. Other toxic air pollutants chlorofluorocarbons (CFC's) come primarily from large, stationary industrial facilities.
Smaller area sources (such as dry cleaners) and indoor sources also can release toxic air pollutants.
Indoor concentrations of VOCs often exceed outdoor concentrations.

Mercury

• Mercury occurs naturally in the earth’s crust. Most people and wildlife can tolerate the extremely low levels of this naturally occurring substance.
• When mercury enters the body it becomes concentrated in tissue, an effect known as bioaccumulation.

Mercury

• Because this element is toxic at very low concentrations, even slight increases in the minute concentrations naturally present in the environment can have serious effects on humans and wildlife.
• Once mercury enters the water it can be converted to its most toxic form, methyl mercury


Traffic- Related Pollutants and Diesel Exhaust
Increased incidence of wheezing,
bronchitis, and asthma
hospitalizations have been linked
to residence near areas of high
traffic density.

Traffic- Related Pollutants and Diesel Exhaust

Diesel particles may enhance allergic and inflammatory responses and may facilitate development of new allergies.

Routes of exposure

• 1- Inhalation: Is the primary route of exposure to air pollution.
2-Ingestion: The material that was originally released into the atmosphere can be ingested as a result of subsequent contamination of water, soil, or vegetation or the consumption of fish from contaminated waters.

Routes of exposure

Some toxic air pollutants (mercury ,lead, polychlorinated biphenyls and dioxins ) degrade very slowly or not at all and thus persist or accumulate in soil and the sediments of lakes and streams.

Systemic effects

• Respiratory system : most of the common outdoor air pollutant are recognized irritants ,with ozone being the most potent irritant.
2. Other systemic effect : Cancer and impaired neurologic development.


Clinical effects
1-Acute health effects
Increased respiratory symptoms such as wheezing, cough and transient decrements in lung function.
More serious lower respiratory tract infections, and increase absenteeism due to respiratory illness.

Clinical effects

2-Long term exposure to outdoor air pollution particularly ozone and related co-pollutants, is associated with decrements in lung function among children and increases in prevalence of chronic obstructive lung disease.

Control of air pollution

1- Engineering methods: by
altering the process
substitution by non pollutant substance
but this is not always possible so..

Control of air pollution

2-Other methods:
Isolation of heavy industries away from cities
Use very tall stacks
Shielding of the dangerous process e.g. Radioactive substances
Appropriate collection of harmful particles, gases and industrial waste
Continuous monitoring of the process
Education and legislation


Control of air pollution
3- Medical methods:
Health education; the benefit of safe environment
Supervision of sanitary collection and disposal of human wastes
Continuous environmental monitoring

Summary

Environment is totality of surrounding conditions.
The atmosphere and water though extensive are not limitless
The 6 Criteria pollutants
Some toxic air pollutants
Systemic effects
Respiratory particulate material Control of air pollution

Thank you

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Good Luck