Environmental disease 1

In this subject you will learn: 1.Air pollution, Pollutants & effects 2.Tobacco smoking 3.Obesity 4. Chemical injures 5. Physical injures


The term environmental diseases refers to lesion & diseases caused by exposure to chemical or physical agents in the ambient , workplace, and personal environments .

Air pollution: Air borne microorganisms have long been major causes of morbidity & mortality. More wide spread are the chemicals and particulate pollutants found in the air especially in industrialized countries . ِ A pollutant is an agent in the environment that cause disease in those who are exposed, thus agents that are naturally present but in abnormal quantities such as ozone may be considered as pollutant.

It may produce acute toxicity directly by induction of inflammation or necrosis or indirectly when an immune response cause hypersensitivity reaction. It may cause chronic inflammation & fibrosis. It may cause degenerative changes leading to organ malfunction as occur in CNS in children with chronic lead poisoning

According to AMA 50% of all illnesses are caused or aggravated by polluted indoor air. These pollutants can make the air quality less than desirable, there effects ranging from allergies to TB and they are actually the cause of death to an estimated 8.5 million annually.

Pollutants & effects

RADON: The common source of radon is uranium that is found in the soil or on the rock on which the house is built Radon gas is colorless & odorless. It enters the house through cracks in concrete walls, floor. Major health effect associated with radon exposure is lung cancer . If person is smoker & has elevated radon level in home ,the risk of lung cancer is increased

Which include mold, bacteria, dust , mites & pollen . Mites grow in damp warm environments Humidity level in the home plays an important role in controlling the environment, that some biological contaminants grow & thrive in A save home humidity level is 30-50%. They can trigger allergic reaction & asthma attacks . Symptoms include sneezing ,coughing ,dizziness, fever & digestive problems . Children & elderly are particularly susceptible to diseases caused by biological agents

They are used in home for controlling pests such as insects & rodents. Other sources include contaminated soil or dust that finds its way into the house. Symptoms of exposure are headache ,dizziness, muscle spasm, weakness and nausea.



It was commonly used in buildings as insulation Its sources are pipe, textured paint & floor tiles . The asbestos fibers are too small to be seen with naked eye, they are inhaled & accumulate in the lung . It can cause lung cancer, mesothelioma ,asbestosis . The symptoms will appeared years after exposure

This is a real problem in the industrial areas .Smog (smoke+fog) ,the visible accumulation of air pollutants is particularly heavy in cities where coal combustion result in release of sulfur oxides into the air which increase morbidity & mortality especially in person with pre existing lung disease. Photochemical oxidant smog results when incompletely burned hydrocarbons release CO & CO2 & Nitrogen oxides.


The action of sun light on these primary pollutants leads to release of secondary pollutants including Ozone & free radicals . The pulmonary changes seen with various air pollutants range from minor irritation to fibrotic diseases to the induction of cancer.


Low level of ozone may be tolerated to healthy individuals but are detrimental to lung function especially in individuals with asthma & emphysema and when combined with particulate pollution . Its toxicity relates to production of free radicals which injure epithelial cells along the respiratory tract

It is an air pollutant and important cause of death from accidents & suicide. It binds Hb with high affinity & causes systemic hypoxia with CNS depression.

Figure 8-6 Adverse effects of smoking: the more common are in bold face.

Agents in smoke have a direct irritant effect on the tracheobronchial mucosa, producing inflammation and increased mucus production
Figure 8-6 Adverse effects of smoking: the more common are in bold face.
Agents in smoke have a direct irritant effect on the tracheobronchial mucosa, producing inflammation and increased mucus production
Chemical substances : 3000-4000



Polycyclic hydrocarbon. B-naphthylamine. Initiation Nitrosamine. Phenol derivatives. Promotion Ammonia. Formaldehyde. Irritation NO SO2 CO

Nicotine increase blood pressure and heart rate

Maternal smoking increases the risk of abortion, premature birth, and intrauterine growth retardation Factors play a role in tobacco smoking: 1- Amount of daily smoking. 2- Tendency to inhale. 3- Duration of smoking habit.

A - Active. B - Passive (involuntary): It is responsible for 3000 lung cancer death in each year in non smoking adults. Young children whose parents smoke in their presence are at a higher risk for respiratory infections such as pneumonia & bronchitis

is a disease of caloric imbalance resulting from excess intake of calories above their consumption by the body that lead to accumulation of adipose tissue of sufficient magnitude to impair health Assessment of obesity 1-body mass index (BMI)  .obese if BMI is above 30kg/sq. m .overweight if BMI is in the range of 25-30kg/sq. m  2-body weight 3-triceps skin-fold thickness 4-mid-arm circumference 5-ratio between waist hip circumferences