ENVIROMENTAL MEDICINE
Series of lectures in Community
Medicine - Dr.Sijal Fadhil Farhood Al-Joborae
M.Sc. (Community medicine) M.B.Ch.B.
ENVIRONMENT
Is the aggregate of all the external conditions &influences affecting the life &development of a person, an organism or a society
ENVIRONMENTAL HEALTH
WHO DEFINITION
Those aspects of human health, including quality of life; that are determined by physical, chemical, biological, social &,psychosocial factors in the environment.
It is also refers to the theory &practice of assessing ,correcting and preventing those factors in the environment that can potentially affect adversely the health of present &future generations.
ENVIRONMENTAL MEDICINE
A branch of medical science devoted to the prevention and management of adverse health outcomes from exposure to hazardous agents at home & community or their overall effects upon environments.
GLOBAL ENVIRONMENTAL HEALTH
The art &science of protecting against environmental factors that may adversely impact human health or ecological balances essential to long term health &environmental quality
Includes (but not limited to) air, food, &water contamination, radiation, toxic chemical, wastes.
GLOBAL ENVIRONMENTAL PROBLEMS
Green house effect &global warming.
Depletion of ozone layer.
Acid rain.
Decrease in tropical forests ,desertification, decrease in number of wild life species.
Marine pollution.
Transgretion of the harmful wastes across borders .
Over population.
GREENHOUSE EFFECT
The effect produced by certain gases on a planet’s atmosphere by raising the temperature of the surface of the planet
thus preventing the outward transmission of long wave radiation from the surface but permitting the inward transmission of short wave radiation from the sun to the surface
GLOBAL WARMING
Global warming is a rise of atmospheric temperature due to higher concentrations of green house gases in the air.
GREEN HOUSE GASES
CO2: It accounts for 65%of global warming by green house effect
METHANE(CH4): 20% of global warming.
.CFC: 10%
NITROUS OXIDE: 6%
CONSEQUENSES OF GLOBAL WARMING
Higher sea levels
Impact on water resources &natural disasters.: It accelerates the normal cycle of rainfall evaporation ,destroying the balance of water supply &demand .
Impact on agriculture.
Impact on animals &plants.
Impact on cities: in urban areas, local temperature increases (heat island phenomenon
DEPLETION OF OZONE LAYER
Reduction in quantity of ozone contained in the stratosphere(12-40 Km from the surface of earth) due to released of green house gases as a result of human activity (chlorine, bromine)
EFFECT OF SOLAR UV RADIATION ON HUMAN HEALTH
-
SKIN
-
Example: sun burn, photodermatosis ,malignant melanoma.
EYE:
Example :acute photo keratitis, photoconjuctevitis, cancer of cornea &conjunctiva.
ACID RAIN
§ It is thought to be formed by sulfur oxide &nitrogen oxide discharged by human activities into air where they become sulfate ,nitrate &absorbed into rain, snow ,fog& dew.
Generally acid rain is defined as having PH LESS THAN 5.6 .Consequences of acid rain include:
Decreases soil fertility.
Damages vegetation.
Affects lake ecosystems.
Decays materials.
Health effects (destruction of mucosal tissue in the lung)
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere.
The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth s ecosystems.
Pollutants
An air pollutant is known as a substance in the air that can cause harm to humans and the environment. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made.
Pollutants can be classified as primary or secondary. Usually, primary pollutants are directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone — one of the many secondary pollutants that make up photochemical smog. Some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.
Major primary pollutants include:
• Sulfur oxides (SOx) - especially sulfur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain. This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.
• Nitrogen oxides (NOx) - especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities. Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NO2 is one of the most prominent air pollutants.
• Carbon monoxide - is a colorless, odorless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
• Carbon dioxide (CO2) - a colorless, odorless, non-toxic greenhouse gas associated with ocean acidification, emitted from sources such as combustion, cement production, and respiration
• Volatile organic compounds - VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.
• Particulate matter - Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosols—those made by human activities—currently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.
• Persistent free radicals connected to airborne fine particles could cause cardiopulmonary disease.
• Toxic metals, such as lead, cadmium and copper.
• Chlorofluorocarbons (CFCs) - harmful to the ozone layer emitted from products currently banned from use.
• Ammonia (NH3) - emitted from agricultural processes. Ammonia is a compound with the formula NH3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous.
• Odors — such as from garbage, sewage, and industrial processes
• Radioactive pollutants - produced by nuclear explosions, war explosives, and natural processes such as the radioactive decay of radon