Contaminación atmosférica: la que se produce como consecuencia de la emisión de sustancias tóxicas.
Efectos sobre la salud: asma, cancer de pulmón, bronquitis, cancer, entre otros.
Agentes perjudiciales
Co2: es un gas cuyas moléculas estan compuestas por dos atomos de oxígeno y uno de carbono.
Dióxido de azufre (so2): Es un gas incoloro con un característico olor asfixiante.

Efectos:
Sequias.
Calentamiento global.
Efecto invernadero.
Deshielo de los polos.

Contaminación agua: es una modificación generalmente, provocada por el hombre, haciéndola impropia o peligrosa para el consumo humano, la industria, entre otros.

Aguas residuales urbanas: un tipo de agua que esta contaminada con sustancias fecales y orina, procedentes de organicos humanos o animales.
Origen industrial: los desechos de las industrias en los lagos, mares y ríos.
Origen agrícola: el uso de productos químicos en los lagos, ríos y mares.
Efectos sobre la Salud:
virus, bacterias y parasitos
enfermedades como: amibiasis y paludismo
Efectosambientales: muerte de especies.
Contaminación de suelo: consiste en la acumulación de sustancias a unos niveles tales que repercuten negativamente en el comportamiento de los suelos
Se produce por:
Contaminación urbana: es la generada en las ciudades a causa de la actividad del hombre.
Contaminación rural: es la generada en las zonas rurales (campos) a causa de la labor del campo.
Contaminación industrial: es la provocada por las industrias
Efectos sobre la salud: parasitosis, encefalitis, fiebre amarilla
The Great Depression is another event that is considered as main long-term cause of the war. The great depression was a harsh economic depression that occurred in the entire world. It is considered as one of the main long-term causesbecause as a consequence of it, Hitler arouse to power in 1933. The great depression left Germany is a serious economic crisis. Germany had 12 million unemployed people by 1932. As a result of the Great depression many countries adapted more radical political regimes. In Germany’s case, the Nazis came to power with fascist ideas to reform the country that eventually ended up as the outbreak of the war.
Before the Great Depression, a treaty was signed between Germany and USSR, the treaty was signed in Rapallo in 1922. By this treaty the Russians and the Germans started diplomatic relations and commit for future cooperation. This treaty was seen suspiciously because there would be military cooperation between the two countries, which meant that Germany would be able to rearm.
Other long-term cause is the failure of disarmament. The Washington Conference in 1921, the London Naval Conference in 1930, the Geneva Disarmament Conference in 1932 and The London Naval Treaty in 1936 are events that occur in order to limit the amount of armament per country. By 1932, Germany left the League of Nations; after the Disarmament Conference where France refused to disarm. By 1936 Japan refused to limit the amount of naval tonnage that it had and left the conference before that, in 1933 it left the League of Nations.
Many countries left the League of Nations before1939; also many small countries lose faith in the League. Events such as the Manchuria Invasion and the Abyssinian Invasion are considered key moments in which the League failed to preserve collective security and also long-term causes of the war.
The Manchuria Invasion in 1931 is considered as a long-term cause of the war because it showed the failure of the League to preserve collective security, it made Japan more aggressive. The League didn’t count on an army of its own so it couldn’t defend Manchuria from the invasion. The members of the League were too affected by the Great Depression so they worried for their own domestic situations. The only powers that were ready to control the situation were USA that was out of the League and Britain was unwilling to act alone.
Another incident that contributed to the failure of the league was the Abyssinian Crisis in 1935. The Italians invaded Abyssinia and the League of Nations was supposed to act and sanction Italy as it was stated in the Article 16; all members and nonmembers of the League should cut any type of relations with a country that started an act of war. The League of Nations instead of sanctioning Italy as it should and cutting relations imposed minor punishment to the Italians, because the league feared that if they imposed several punishments, the Italians might possibly make an alliance withthe Germans. The alliance between Germans and Italians happened and the League lost another permanent member.


The Appeasement Policy (Short- term causes)
The Appeasement Policy was started in 1930 by Britain, in an attempt to solve international disputes by satisfying complains through negotiation and compromise. Examples of the appeasement policy are the Munich Conference, the takeover of Czechoslovakia and Anschluss.
The takeover of Czechoslovakia in 1
Efectos:
incendios forestales
muerte de especies, animales.
Contaminación sónica: es la ocasionada por los ruidos.
Efectos psicológicos:
Fatiga auditiva
Encubrimiento
Sorderas profesionales
Traumatismos profesionales
Efectos psicoficologicos:
Interrupción del sueño
Disminución del rendimiento
Estado de ansiedad

Medidas preventivas
Reciclar
Construir instalaciones industriales fuera de centros urbanos
Construir filtros colectivos de vapor
Utilizar gasolina sin plomo
Hombres tomar acciones individuales