THE DANGERS OF SMOG

Sometimes urban authorities issue warning about the form of air pollution known as smog ( a made up word that combines smoke and fog). Though acute smog episodes are rare, they can be deadly Twenty people died and thousands fell ill during a smog alert in Donora, Pennsylvania, in 1948; and more than 4,000 people succumbed to london’s “killer smog” of 1952. Those who died in these dramatic incidents were primarily the very young , the very old, and those with chronic respiratory diseases. But many people in lower-risk categories may have been affected to some extent.

There are actually two types of smog; the London type and Los Angeles type. The London variety, blamed for thousands of deaths in Europe and the eastern United States. Is more correctly termed sulfur-dioxide smog. It is caused by the burning of fossil fuels (primarily coal with high sulfur content); high levels of sulfur dioxide and ozone result, combined with particulate matter and foggy air. Sulfur dioxide smog poses a special threat; it inhibits the sweeping action of the cilia that line our respiratory passages, allowing smog particles and chemicals impair breathing so markedly that people with chronic respiratory problem may die. Impaired breathing can also aggravate heart problems. Reduction of the use of high-sulfur fuels has significantly decreased the occurrence of London-type smoge.

Los Angeles –type smog, more properly called photochemical smog, result from the interaction of sunlight with temperature inversions and exhaust emission from automobiles. This type of smog occurs in areas with poor air circulation (Valleys, for example) , especially those where there in sunny weather and low humidity . In Los Angeles, a layer of cool ocean air may slip in under the normally warm, stable air above the city. This cool air becomes trapped by the warmer air , a phenomenon a called a temperature inversion . Motor vehicle emissionrise through the cool air but can not penetrate the warm layer, which acts like a lid on the Los Angeles basin. Thus p[pollutants are trapped and subjected to the action of sunlight , which produce additional pollutans (such as ozone). The pollutans do not disperse until the weather change and the inversion lifts.

WHO IS AT GREATEST RISK FROM AIR POLLUTION?

Individuals vary considerably in their susceptibility to unclean air. Those with heart disease and those with respiratory ailments such as asthma, bronchitis, and emphysema are likely to feel the effects of air pollution. But even those who do not have hearth disease or respiratory illnesses may be affected by air pollution to some degree: although there is no proof that air pollution causes disease, people in heavily polluted areas suffer more short-term respiratory ailments and chest infections than do those in clean –air zones. Cigarette smokers , in particular, run a higher risk of contracting pollution-related ailments, because the effects of of cigarette smoke and air pollution seem to rein force each other.

PROBLEMS WITH FLUOROCARBONS

Although fluorocarbons, chemical compounds used as propellants in aerosol spray cans –are not know to have a direct effects of human beings, they are nevertheless considered a threat to health by a growing number of scientists . Evidence has accumulated to suggest that because these compounds are inert and do not react with the other contents of the spray cans, they float up unchanged to the stratosphere, where they set of chemical reactions that may gradually destroy the layer of ozone that lies ten to forty miles above the earth. This ozone layers is important to living things on earth because it absorbs wavelengths of ultraviolet sunlight. Among the possible consequences of ozone depletions, scientist fear an increase in the incidence of skin cancer and a negative effect on human immune responses.

CONTAMINATING SUBSTANCES IN AIR

The principal pollutant responsible for air pollution are sulfur oxides , nitrogen oxides, carbon monoxide, hydrocarbons, and particulate matter.

Major air pollutant and their effect

AIR POLLUTION

AIR POLLUTION

The threshold concept is the basis for federal and state laws regulating the level of hazardous substances to which people may be exposed in the workplace. Some government regulations also control the substances discharged into the air people breathe. Still others set acceptable levels for contaminants in the water we drink and the food we eat. But the problem is determining what constitutes a safe level. Allowances must be made for the lower thresholds of the very young, the very old, the sick, the disabled, and others who are at special risk because of some genetic, developmental, nutritional, physiological, or psychological character.

At this time, government, industry, and private citizen are in the midst of a heated, ongoing debate over all forms of pollution. As you will see in this chapter, we as individuals must make choices as to the types and quantities of pollution to which we are exposed; and then we can take action to make our concerns known to those who have some control over pollution.

Air pollution is the presence in the air of contaminant that do not disperse properly and that interfere with human health. People once believed that earth had an unlimited supply of breathable air . But now there is widespread doubt; We now know that the air –most vital of our natural resources- must be protected before it is irreversible fouled by wastes from industries, homes, and automobiles.

How Air pollution endangers Our health
Air pollution poses its most immediate threats to the respiratory system, but over time it can also harm other parts of the body, including the brain and the heart.

Environmental Health

Pesticides. Drugs yes. Plastics. Fertilizers. Fuels. Synthetic fiber. Building materials. Food addictives. Detergent. The list is endless. The spoil of the twentieth –century technological revolution line our cupboards, refrigerator, and medicine cabinets, hang in our closets, cover our lawn, furnish our home, and occupy our garages. New technological and new chemical compounds –some 1,000 new compounds are developed each year in the united state alone- have been undeniable boon to humanity. They have increased food production, conquered many infectious diseases, and enabled more people than ever to enjoy “the good life. But it is becoming increasingly clear that all of this progress has a cost. The most glaring consequence is an increase in environmental pollution.

Pollution refers to any substance or energy that contributes to the development of undesirable. It includes anything that provides extra energy-in any form- leading to harmful environmental changes. For example, noise is extra energy that can cause many changes in plants and animals –including human beings.

Our bodies can cope with a certain amount of pollution, via built-in systems for self –cleansing and self renewal. The body’s repair mechanisms are constantly replacing damaged body chemicals, cell part and even whole cells. The body also has a system of chemical known as enzymes; they work –particularly in the liver – to break down or metabolize many unwanted or toxic chemical, both natural and synthetic.

These protective systems operate constantly. If the damage from toxic substances remains within the normal rate breakdown and replacement, it will not usually have a harmful effect on the individual. We say that the person’s exposure is below the effect’s threshold.
If the exposure exceeds the threshold, however, the rate at which the individual’s body is damaged will exceed the rate at which it can repair itself , and the individual may suffer a loss of body function that may lead to a permanent disability.

Experts agree as to weather this threshold concept applies to cancer – causing chemical, or whether a single molecule of certain chemicals is sometimes sufficient to cause the disease.

Pollution Prevention

The key element of life-cycle design is Life-Cycle Assessment (LCA). LCA is generally envisioned as a process to evaluate the environmental burdens associated with the cradle-to-grave life cycle of a product, process, or activity. A product’s life cycle can be roughly described in terms of the following stages:

1. Raw material
2. Bulk material processing
3. Production
4. Manufacturing and assembly
5. Use and service
6. Retirement
7. Disposal

Maintaining an objective process while spanning this life cycle can be difficult given the varying perspective of groups affected by different parts of that cycle. LCA typically does not include any direct or indirect monetary costs or impacts to individual companies or consumers.

Another fundamental goal of life-cycle design is to promote sustainable development at the global, regional, and local levels. There is significant evidence that suggests that current patterns of human and industrial activity on a global scale are not following a sustainable path.

Changes to achieve a more sustainable system will require that environmental issues be more effectively addressed in the future. Principles for achieving sustainable development should include (Ref. 2):

1. Sustainable resource use (conserving resources, minimizing depletion of nonrenewable resources, using sustainable practices for managing renewable resources). There can be no product development or economic activity of any kind without available resources. Except for solar energy, the supply of resources is finite. Efficient designs conserve resources while also reducing impacts caused by material extraction and related activities. Depletion of nonrenewable resources and overuse of otherwise renewable resources limits their availability to future generations.

2. Maintenance of ecosystem structure and function. This is a principal element of sustainability. Because it is difficult to imagine how human health can be maintained in a degraded, unhealthy natural world, the issue of ecosystem health should be a more fundamental concern. Sustainability requires that the health of all diverse species as well as their interrelated ecological functions be maintained. As only one species in a complex web of ecological interactions, humans cannot separate their success from that of the total system.

3. Environmental justice. The issue of environmental justice has come to mean different things to different people. Theodore (Ref. 3) has indicated that the subject of environmental justice contains four key elements that are interrelated: environmental racism, environmental health, environmental equity, and environmental politics. (Unlike many environmentalists, Theodore has contended that only the last issue, politics, is a factor in environmental justice.) A major challenge in sustainable development is achieving both intergenerational and intersocietal environmental justice. Overconsuming resources and polluting the planet in such a way that it enjoins future generations from access to reasonable comforts irresponsibly transfer problems to the future in exchange for short-term gain. Beyond this intergenerational conflict, enormous inequities in the distribution of resources continue to exist between developed and less developed countries. Inequities also occur within national boundaries.

Life cycle is a perspective that considers the true costs of product production and/or services provided and utilized by analyzing the price associated with potential environmental degradation and energy consumption, as well as more customary costs like capital expenditure and operating expenses. Unfortunately, a host of economic and economic-related terms have appeared in the literature. Some of these include total cost assessment, life-cycle costing, and full-cost accounting.

Unfortunately, these terms have come to mean different things to different people at different times. In an attempt to remove this ambiguity, the following three economic terms are defined below. The reader is also referred to figure below for additional details.

1. Traditional costing procedure (TCP). This accounting procedure only takes into account capital and operating (including environmental) costs.

2. Comprehensive costing procedure (CCP). The economic procedure includes not only the traditional capital and operating costs but also peripheral costs such as liability, regulatory related expensive, borrowing power, and social considerations.

3. Life-cycle costing (LCC). This type of analysis requires that all the traditional costs of project or product system, from rawmaterial acquisition to end-result product disposal, be considered.

The TCP approach is relatively simple and can be easily applied to studies involving comparisons of different equipments, different processes, or even parts of processes. CCP has now emerged as the most realistic approach that can be employed in economic project analyses. It is the recommended procedure for pollution-prevention studies. The LCC approach is usually applied to the life-cycle analysis (LCA) of a product or service. It has found occasional application in project analysis.

The remainder of this subsection on pollution prevention will be concerned with providing the reader with the necessary background to understand the meaning of pollution prevention and its useful implementation. Assessment procedures and the economic benefits derived from managing pollution at the source are discussed along with methods of cost accounting for pollution prevention. Additionally, regulatory and nonregulatory methods to promote pollution prevention and overcome barriers are examined, and ethical considerations are presented. By eliminating waste at the source, all can participate in the protection of the environment by reducing the amount of waste material that would otherwise need to be treated or ultimately disposed; accordingly, attention is also given to pollution prevention in both the domestic and business office environments.

Source Reduction
Recycling
Treatment
Ultimate Disposal
Pollution Prevention Hierarchy