Essay Air Pollution

emissions during this period; nitrogen oxides being one of the most harmful pollutants present in vehicle exhaust. Incomplete fuel combustion also results in volatile organic chemicals being emitted into the air. Henceforth, pollutants are not only generated from burning fossil fuels but also from other sources.

Methane gas is released from landfills and waste disposal sites during the decomposition of garbage, while Volatile organic chemicals are emitted by various household products. These pollutants can also originate from natural sources like forest fires, which release particulates and Volatile organic chemicals into the air. Airborne particulate levels are increased by ultrafine dust particles caused by water and weather erosion. Additionally, volcanoes emit sulfur dioxide and volcanic ash that can darken the sky over a wide area and impact the atmosphere of the Earth. The eruption of Mount Pinatubo in 1991 led to enough volcanic ash being deposited in the upper atmosphere to lower global temperatures for two years. However, unlike pollutants resulting from human activities, naturally occurring pollutants have a short duration in the atmosphere and do not cause permanent changes.

Introducing pollutants into the atmosphere often leads to chemical reactions that generate more harmful compounds. Weather patterns can influence air pollution, either trapping it in valleys or carrying it to remote pristine environments. The troposphere, which is the lowest layer of the atmosphere and where most weather events occur, experiences local and regional pollution. It extends from the earth's surface up to approximately ten miles high. If pollutants were evenly spread throughout the troposphere, their coverage would be extensive and air pollution would be less noticeable. However, pollution sources tend to be concentrated, particularly

in urban areas. Under specific weather conditions like thermal inversion, a layer of cooler air becomes trapped near the ground due to warmer air above.

When pollutants are trapped in the lower layer, it is due to a decrease in normal air mixing. This effect can be exacerbated by local topography, such as when an area surrounded by mountains becomes a pollution trap. One example of concentrated local pollution is smog, which is typically trapped by a thermal inversion. In the past, burning coal was the primary cause of smog and it was so severe that it caused darkness in midday sky in 19th-century London, leading to the need for street lights to be turned on at noon. However, nowadays, burning gasoline in motor vehicles is usually the main source of smog in most regions. Photochemical smog occurs when oxides of nitrogen and volatile organic compounds react with sunlight as their power source within the atmosphere. Smog includes ozone, which is an oxygen gas variant consisting of three atoms instead of two. Ozone present in the lower atmosphere has detrimental effects including vegetation damage, tree mortality, lung tissue irritation, and rubber corrosion. Environmental officials measure ozone levels to determine the severity of smog.

High levels of ozone often indicate the presence of other pollutants like carbon monoxide. Moisture in the atmosphere can cause sulfur dioxide and nitrogen oxides to turn into acid droplets, which contribute to smog. These acidic particles can harm respiratory health and corrode materials such as limestone, marble, and metals. The erosion caused by smog acids has a global impact on valuable artifacts worldwide, including famous landmarks like the Parthenon

temple in Athens, Greece, and the Taj Mahal in Agra, India. Pollution from nitrogen oxides and sulfur dioxide can travel long distances through winds in the troposphere before descending as acidic rain or snow.

Acid precipitation can harm plant leaves and make lakes too acidic for fish and other organisms, resulting in the decline of sensitive species like brook trout in numerous lakes and streams across the eastern United States. Smog not only impairs visibility but also creates unpleasant conditions for outdoor activities. Certain groups, including young children, the elderly, and individuals with asthma or heart disease, are especially susceptible to smog's effects. It can lead to headaches, dizziness, difficulty breathing, and in severe cases, sickness or even death from carbon monoxide poisoning. Donora, Pennsylvania experienced a tragic incident in 1948 when dense local smog claimed nineteen lives. Additionally, the well-known London Fogs proved fatal with over 3000 deaths occurring in 1952 followed by another 700 deaths in 1962.

Despite the implementation of stricter pollution controls and reduced reliance on coal for heating, chronic smog remains a concern. Adverse weather conditions can lead to accidental releases of toxic substances with disastrous consequences, even if they are not immediately deadly. An incident that exemplifies such an accident occurred in 1984 in Bhopal, India when a thermal inversion caused an American-owned factory to release methyl isocyanate, resulting in at least 3300 deaths. The impact of air pollution goes beyond regional boundaries and has global effects as well. The stratosphere, located between ten miles and thirty miles above sea level, contains significant amounts of ozone. Ironically, within urban smog, ozone acts as a pollutant when present

at lower levels.

The ozone layer is essential for safeguarding against dangerous UV-B solar radiation and shielding against DNA damage as well as the heightened risk of cancer. Found in the stratosphere, it confronts a peril from pollutants such as chlorofluorocarbons (CFCs). CFCs have been utilized in refrigerants, manufacturing, and formerly in aerosol cans. Once these molecules reach the stratosphere, they are disintegrated by UV radiation, releasing chlorine atoms. These chlorine atoms subsequently interact with ozone, causing its breakdown into oxygen molecules that do not absorb UV-B.

The presence of chlorine in the atmosphere acts as a catalyst and participates in various chemical reactions without being changed or reduced. This means that one chlorine atom has the ability to destroy up to 100,000 ozone molecules in the stratosphere. Furthermore, pollutants like nitrous oxide from fertilizers and methyl bromide pesticide also contribute to the depletion of atmospheric ozone. These harmful factors are gradually causing the protective ozone layer in the stratosphere to thin out. In the Antarctic region, the ozone layer essentially disappears temporarily each year. Despite recent significant reduction in CFC usage, CFC molecules that have already been released into the lower atmosphere will continue their journey to the stratosphere for many years, further depleting ozone levels.

Scientists predict that the accumulation of greenhouse gases, such as carbon dioxide, methane, nitrous oxide, and CFCs, will result in a warmer earth. This increase in temperature is expected to have detrimental effects on human health and food production. Experts anticipate an increase in skin cancers and cataracts due to the heightened exposure to sunlight. Additionally, specific food crops are likely to experience reduced yields. These greenhouse

gases function similarly to glass in a greenhouse by allowing sunlight to pass through while reflecting heat back towards the earth's surface. As a result, heat becomes trapped in the atmosphere. It is worth noting that carbon dioxide has seen a significant 25% rise in the atmosphere primarily due to coal burning and fossil fuel usage.

Projections suggest that the average global temperature will increase by 1.0 to 3.5 degrees Celsius (1.8 to 6.3 degrees Fahrenheit) in the next century, indicating a trend of rising temperatures. The warmest years on record occurred from 1987 to 1997, but scientists are cautious about officially attributing this to global warming as natural climate variations over different time periods can influence these findings. To confirm a significant change, extensive data over many years is necessary. However, there is widespread agreement that global warming is imminent. Its impacts will vary across regions and encompass more extreme weather events like increased rainfall during wet periods, prolonged droughts, and stronger storms.

While the impacts of future climate change are uncertain, some forecasts suggest that certain regions, like the western United States, could experience improved agricultural production due to extreme weather patterns. This is because these areas are projected to have higher temperatures and increased precipitation. However, it is important to note that prolonged decreases in rainfall can lead to severe droughts and significant declines in agriculture output, particularly in Africa. Additionally, as global temperatures continue to rise, there is a possibility of partial melting of polar ice caps which would result in an estimated twenty-inch rise in sea level by 2050. The consequences of such a substantial increase include coastal

city flooding, displacement of populations from low-lying islands, and complete submergence of coastal wetlands.

If the predicted rise in sea levels continues, the Florida Everglades will be completely submerged within the next 50 years. This could result in an increase in diseases such as malaria, currently prevalent in tropical areas but potentially spreading to temperate regions between the tropics and polar zones. The impact of climate change goes beyond human health; numerous plant and animal species may face extinction due to their inability to adapt to warmer environments. Additionally, indoor pollution poses a significant threat, particularly since most of our time is spent indoors. Indoor pollutants include tobacco smoke, radon gas (an invisible radioactive gas that can enter homes from certain soil areas), and chemicals emitted by synthetic carpets, furniture, pesticides, and household cleaners.

Asbestos, a nonflammable material commonly used in insulation, can release airborne fibers and cause the lung disease asbestosis when disturbed. Indoor air pollutants tend to accumulate at higher levels indoors compared to outdoor environments where natural air currents disperse them. In fact, indoor air may contain 2 to 5 times or even over 100 times more pollutants than outdoor air. This is particularly concerning because people spend up to 90 percent of their time indoors for various activities. The inefficient or improper ventilation of heaters also poses a significant risk. To combat local and regional air pollution, the United States implemented the Clean Air Act in 1970, which was later amended in 1977 and 1990.

The law requires specific pollutants to be present in the air, including particulate matter, lead, carbon monoxide, sulfur dioxide, nitrogen oxides, volatile organic compounds, ozone, and toxic

substances. In areas with cleaner air, more stringent standards are enforced to prevent pollution from spreading there. National parks strive to maintain the same level of cleanliness as when the law was initially established. Additionally, the law establishes deadlines for achieving these standards. The Environmental Protection Agency (EPA) is responsible for strengthening and enforcing these regulations while state governments and local air pollution control districts handle daily efforts to combat pollution.

Some states, like California, have implemented more rigorous air pollution regulations. To enforce these regulations, authorities measure the levels of pollutants in the atmosphere and their origins. This is accomplished by sampling the open air for designated pollutants and quantifying their quantities in parts per million or other units. Moreover, measurements are taken at industrial smokestacks and car tailpipes to identify the pollution originating from specific sources. Pollution control entails using end-of-the-pipe devices to capture already emitted pollutants and restricting the amount of pollutants produced initially.

Pollution reduction is achieved through the use of end-of-the-pipe devices such as catalytic converters in cars and various filters and scrubbers in industrial plants. Catalytic converters in vehicles clean exhaust gases by passing over coated beads that contain metals to convert harmful substances into less harmful ones. Although initially effective at reducing pollution at a low cost, stricter air pollution standards have increased the cost of further air purification. To address this issue, some industrial polluters collaborate to collectively reduce overall pollution levels. For instance, a power company may invest in more efficient pollution control at another plant or factory where it can be done at a lower cost to meet its pollution

control requirements. However, despite advancements, end-of-the-pipe controls have limited effectiveness.

Efforts to control pollution have shifted towards prevention, with a focus on maintaining clean air. To achieve this goal, gasoline has been reformulated multiple times to improve combustion and manufacturing processes have been redesigned to minimize waste generation. Car manufacturers are also considering alternatives such as electric vehicles and cleaner-burning fuels. In architecture, buildings are now designed to optimize natural elements like sunlight, shade, and breezes in order to reduce reliance on fossil-fuel-powered heating and cooling systems. Additionally, individual choices play a significant role in air quality; choosing public transportation over driving reduces pollution by decreasing the number of emission-generating vehicles on the road.

During periods of high smog levels, pollution control authorities often advise people to avoid using cars. In Paris, France, authorities provide temporary free bus and subway travel to encourage the use of public transportation during times of poor air quality. To address indoor pollution, it is important to give attention to each building and sometimes even each room individually. Effective ventilation helps replicate outdoor air circulation and continuously reduces indoor air pollutants. The next most effective measure after improved ventilation is likely banning smoking in public areas. Asbestos insulation can be safely removed or sealed with protective sheathes to prevent its disturbance and release into the air. Moreover, sealing foundations and installing special pipes and pumps can prevent radon infiltration into buildings.

On a global scale, pollution control standards are established through complex negotiations among nations. Typically, developed countries, who have already experienced a phase of rapid and dirty industrialization, are willing to demand cleaner technologies. However, less

developed nations, aiming for swift economic growth, show less enthusiasm towards implementing pollution controls. They instead seek lenient deadlines and financial assistance from developed nations to afford the costly changes required to reduce pollutant emissions in their industrial processes. Despite these differences, numerous significant international agreements have been achieved. For example, in 1988, the United States and 24 other countries reached the Long-Range Transboundary Air Pollution Agreement, committing to maintain their nitrogen oxide production - a major contributor to acid rain - at current levels.

The Montreal Protocol, adopted in 1987 and strengthened in 1990 and 1992, resulted in a decrease in CFC production by most countries. Subsequently, the United Nations Framework Convention on Climate Change negotiated a treaty in 1992 to address global warming through collaborative efforts. This treaty took effect in March 1994 and has been legally accepted by 160 out of the 165 participating countries. At the Third Conference of the United Nations Framework Convention on Climate Change held in Japan in December 1997, over 160 nations officially ratified the Kyoto Protocol. This agreement mandates industrialized nations to reduce their greenhouse gas emissions to levels at least 5 percent lower than those recorded in 1990 between the years of 2008 and 2012. Despite being the largest emitter of greenhouse gases, the United States has been hesitant to support these ambitious measures.

Although developing countries like China and India do not have emissions goals, the U.S. Senate may still reject the ratification of the Kyoto Protocol. Nevertheless, global pollution emission levels have been successfully decreased by implementing different antipollution measures. From 1970 to 1995, the United States experienced a notable reduction

of almost 30 percent in total emissions of major air pollutants despite a population increase of 28 percent and a 116 percent rise in vehicle miles traveled.

Air pollution control involves a competition between reducing pollution from specific sources like factories and cars, and the rapid growth of these sources. The rising number of cars and miles driven in American cities indicates that smog levels will likely increase. Additionally, developing countries are investing in their industries and citizens are purchasing cars as soon as they can financially. These shifts pose a hazardous situation for the global atmosphere. Therefore, it is vital to implement new measures to mitigate air pollution during these ongoing trends.