Air Pollution The air that surrounds us is a mixture of 78% nitrogen; 21% oxygen; less than 1% of carbon dioxide, argon, and other gases; and varying amounts of water vapor. Any other particles, gases or unoriginal constituents hanging in the air which are not part of its original composition are called 'Pollutants' and this kind of air is called Polluted Air. Even inhaling small amounts of such air pollutants can have serious effects on one's health and leads to environmental problems.

We can see some air pollutants such as the reddish-brown haze in smog; however, other air pollutants, including some of the most dangerous, are invisible.

Air pollution can be natural or human-made. Air pollution occurs naturally during volcano eruptions, forest fires, or dust storms. This has been an occasional problem for humans. However, during the past hundred years, air pollution created by humans has become a major, persistent problem.

Outdoor Air Pollution

Air pollution is a serious problem in the United States and many other industrialized countries. In the United States, the Environmental Protection Agency, is charged with identification and regulation of pollutants in the ambient air that may cause adverse Effects on Health. The current National Ambient Air Quality Standards are for six pollutants. Despite these federal and state regulations, many cities and regions in the United States currently do not meet these primary standards. Epidemiologic research, human clinical studies and animal toxicological studies continue to provide evidence for adverse Effects on Health of ambient air pollutants, even at exposure levels below the current standards. The major sources of air pollutants are:

Combustion of fossil fuels: These are divided into mobile sources such as motor vehicles, stationary sources such as power plants and factories, and other sources such as barbecues and fireplaces. Tailpipe emissions from motor vehicles are a complex mixture of carbon monoxide, oxides of nitrogen, hydrocarbons, diesel exhaust particles, and other particulates including lead oxide from tetraethyl lead contained in leaded gasoline.

Photochemical reactions: Oxides of nitrogen and hydrocarbons interact in the atmosphere to produce Ozone (O3) as a secondary pollutant.

Power Plant Emissions: These release Sulphur dioxide (SO2) and particulates in the atmosphere. Coal and oil contain sulphur, leading to atmospheric formation of sulfates. Automobiles release oxides of nitrogen, leading to atmospheric formation of nitrates. Aerosolized acid sulfates contribute to acid rain.

Waste incinerators, industry, smelters. These point sources release acid aerosols, metals and organic compounds that maybe hazardous for human health. One example of the numerous hazardous chemicals emitted by these sources is methyl isocyanides that was accidentally released at Bhopal in India in 1984, resulting in 3000 deaths due to pulmonary edema. Some of the air toxins, such as polycyclic aromatic hydrocarbons, are known carcinogens.

Lungs are the major target of common outdoor air pollutants; especially vulnerable are children, asthmatics, and people with chronic lung or heart disease. The serious toxicity associated with lead exposure is discussed subsequently under Industrial Exposures. The major air pollutants and the mechanisms responsible for their adverse Effects on Health are summarized briefly.

Ozone

Ozone is a major component of smog that accompanies summer heat waves over much of the United States. Exposure of exercising children and adults to as little as 0.08 ppm produces cough, chest discomfort, and inflammation in the lungs. Asthmatics are especially sensitive and require more frequent visits to emergency rooms and more hospitalizations during smog episodes. It is not known whether these acute changes lead to chronic, irreversible lung injury. Ozone is highly reactive and oxidizes polyunsaturated lipids to hydrogen peroxide and lipid aldehydes. These products act as irritants and induce release of inflammatory mediators, cause increased epithelial permeability and reactivity of the airways, and decrease ciliary clearance. The highest inhaled dose is delivered at the bronchoalveolar junction; however, ozone also causes inflammation of the upper respiratory tract.

Nature and Sources of Ozone sensitive and edgy gas which is in the shape of oxygen is O3 that is Ozone. This gas is the chief producer of smog, which is one of the constituent of Air pollution.

Ozone chemically reacts, by oxidizing internal tissues of the body with which it impinges; for example when it impinges with the lungs. It is also potent enough to break down other materials such as rubber compounds.

Formation of Ozone takes place when the sunlight impinges on carbon-based...

Effects on Health
Ozone behaves as a strong respiratory irritating agent at the levels usually noticed in nearly all of our country's urban regions during the months of summer. Signs of effects are shortness of breath, inhaling deeply causes significant chest pain, wheezing and coughing.

Detailed studies on the cons of protracted exposures (6 1/2 hours) to comparatively lower Ozone levels have found dysfunctional lungs, biological proof of redness of the lung lining and respiratory inconvenience.

Research proves that when animals are exposed to Ozone, there's an increase in getting easily affected to bacterial pneumonia infection.

People at Risk

Country's Environmental Protection Agency (EPA) has described and revealed three sets of citizens who are especially in danger from increasing ozone levels:

1. Patients, already suffering from Respiratory Disease:

Pre-existing lung disease patients (e.g., chronic bronchitis, emphysema, asthma) are already enduring trimmed working of lungs and subsequently cannot afford further deterioration in lung function because of exposure to ozone.

2. A General sub-group in Public, known as Responders:

Studies have revealed that a certain group in the general public gets affected by ozone exposure during exertions with sufficient damage to lung function as compared with the normal, bearable response of the whole group under the spotlight. Right now, there's no specific way to know about these responders before exposure to ozone, although, EPA's forecast is this particular sub-group make up only 5 to 20% of the overall U.S. population.

3. Individuals Who Commute Outside:

Large numbers of real world and laboratory ozone exposure studies have determined that individuals who excessively exert, or otherwise engage in activities which heighten up their breathing process, get affected more resoundingly to ozone exposure than folks staying and relaxing under one shed.

Ozone Air Pollution: Fact Sheet

Ozone (O3) is a highly reactive gas that is a form of oxygen. It results primarily from the action of sunlight on hydrocarbons and nitrogen oxides emitted in fuel combustion. Ozone reacts chemically (oxidizes) with internal body tissues that it comes in contact with, such as those in the lung. It also reacts with other materials such as rubber compounds, breaking them down.

Before the year of 1997, for nearly two decades the federal air quality standard for ozone had been 0.12 parts per million (ppm) averaged over one hour, but tests conducted upon healthy grown-ups and adolescents practicing medium level exercise during exposition to this kind of higher ozone levels and at lower levels too, presents a definite reduction in the breathing ability of an individual.

Between the months of May and October, due to raised temperatures and the increased amount of sunlight combine with the stagnant atmospheric conditions that are associated with ozone air pollution episodes ozone levels typically rise. During the months of summer it is usually noticed when the ozone levels typically rise, it acts as a powerful respiratory agent in almost all of our country's urban area. Signs of effects are:

shortness of breath chest pain when inhaling profoundly wheezing and coughing Long-term, repeated exposure to high levels of ozone may cause large reductions in lung function, inflammation of the lung lining and increased respiratory discomfort. According to an EPA estimate 5 to 20% of the total U.S. population is especially vulnerable to the harmful effects of ozone air pollution. The EPA has identified the three groups of people who are particularly at risk from high ozone levels: People already suffering from respiratory disease; those already afflicted with lung disease such as asthma, chronic bronchitis and emphysema Individuals engaged in outdoor exercise Responders who are more susceptible to ozone exposure There is a difference between the man-made-ground -level ozone in three lower atmosphere troposphere) and the layer of ozone in the upper atmosphere (stratosphere) and the two should not be confused with each other. The natural protective layer of ozone in the upper atmosphere protects us from the sun's harmful ultraviolet rays, on the contrary man-made ground -level ozone…