Human activities inevitably and increasingly introduce material and energy into the environment; when that material or energy endangers or is liable to endanger man's health, his well-being or his resources, indirectly or directly, it is called a pollutant. A substance may be considered a pollutant simply because it is in the wrong place, at the wrong time, and in the wrong quantity.

Pollutants can affect man with direct effects such as: acute effects from exposure to a toxic pollutant reaching man through air, water or food; long-term effects due to prolonged exposure to a pollutant at levels lower than those giving rise to overt toxic effects; synergistic interaction between pollutants or between a pollutant and malnutrition or disease; genetic effects that are manifested in future generations. Indirect effects on man may result from reduction of the food supply or deterioration of the environment. Such effects include: damage to plants and animals; disruption of ecological cycles such that a previously harmless species becomes a pest; damage to the human habitat (air pollutants that destroy forests and corrode buildings); water pollutants that destroy the recreational value of inland waters; alteration of the global climate (this is considered to be a future threat).

Fungi are responsible for by far the greatest number and diversity of plant diseases. All crop plants are apparently attacked by some variety of fungus; often a dozen or more different fungi induce disease on a single species. The distance to which fungus spores may be carried by air currents, for example, is very great. Because of this and because of their astonishing productivity, fungi are responsible for a much larger number of the rapidly spreading, hence epidemic diseases, than are viruses or bacteria. It is the sporadic nature of this disease that brings about the greatest hardships on the individual farmer.

There is the correlation between the mode of dissemination of the fungus and its relation to the host. In general leaf, stem, and fruit diseases are caused by airborne or insect-carried fungi, root diseases by soil inhabiting species. Some vascular wilts are caused by soil fungi, some by fungi possessing insect vectors.

Stress denotes a broad range of biological and psychological reactions to environmental influences; as such, it is an essential component of the equipment that enables man to survive in an hostile environment. However, stress as a traditional method of adaptation has become inadequate in the psychological, social, and economic circumstances of modern society; it is this inadequate adaptation to change that increases the risk of disease. Certain psychosocial situations are potentially pathogenic because they induce in some individuals inadequate adaptational reactions. Stress is induced when a situation is interpreted by the individual, consciously or not, as a threat to his goals, integrity or well-being. Thus noise, dirt, bad air-conditioning, quarrelsome colleagues, lack of personal contact, new responsibility may be stressful to one individual but not to another.

Too much stress is associated with numerous physical and mental disturbances, for example of appetite, sleep, energy level, self esteem, memory, decision-making, concentration, as well as clinical mental and physical conditions. Neurosis, depression and anxiety disorders are aggravated by stress.

Corrupt practices in business include diversion of company funds, tax evasion, and the use of bribery, intimidation and fraud. High company officials involved in corruption or seeking to extend the power of the company may offer bribes to public officials in return for favours. Commercial pressures on companies to improve performance increase susceptibility to unethical behaviour. Establishing criminal liability in such cases is a matter of law and evidence, generally with the requirement that the manager should know of the wrongdoing or be willfully blind to actions by a subordinate.

Corporate crime differs from white collar crime in that the latter is solely for the benefit of the individual, whereas corporate crime serves the corporate entity, even though in some cases the interests of the company and an individual may be connected. Embezzlement of funds from your employer is white collar crime. Deliberate inflated invoicing, which siphons funds from your clients' into your company's accounts, could be either corporate crime or white collar crime or both, depending on whether the perpetrator is able to take personal gain from the action.

A distinction can be also be made between unethical corporate activity undertaken at the discretion of a company employee and that undertaken with the tacit encouragement of, or by instruction of, superiors. Examples include cases where pollutants are dumped illegally to save disposal costs. It is considered impractical for top executives to know all the decisions taken by subordinates. In some cases such executives make it clear that they do not care how a job is done, provided it gets done. In other cases they deliberately turn a blind eye, or implicitly agree to it. And without in any way condoning unethical activity, executives may reward those subordinates who do get a job done under difficult circumstances. In all such cases the executives remain shielded from the blame by plausible deniability, although several countries have introduced new legislation to ensure that directors of companies are held liable for the criminal activities of the company and its employees.

Inflammatory processes resulting from infections of bronchi and lungs, scarring and tissue destruction, as well as impaired pulmonary circulation, are frequent lung disorders. Infants and the elderly are especially vulnerable to acute respiratory infections, which can be fatal. Since the lungs literally filter the venous blood drainage from the entire body, they often become involved secondarily by blood-borne processes; many malignant tumours eventually metastasis to the lungs. More important still is the steadily rising incidence of primary malignancy of the lung and its relationship to cigarette smoking and environmental pollution.