Air Pollution and Air Quality Control and Noise Pollution Essay

Air Pollution and Air Quality Control

All higher living organisms require air to survive (Nathanson & Schneider, 2018). Air pollution has been a serious global problem which calls for international attention. This essay aims at discussing topics related to air pollution and air quality control.

According to Nathanson and Schneider (2018), the discovery of fire is believed to have been the origin of air pollution when shaping gold and copper, as well as clay glazing in 4000 BC. Coal became a source of air pollution in 1000 AD when it was utilized as fuel. In the early 14th Century, the burning of coal was prohibited by King Edward 2 due to air pollution in London. In the 17th Century, air pollution increased due to the conversion of coal to coke for iron smelting, the use of steam engines, and in the industrial revolution.

Measures to control air quality began in the 20th century due to the fatal episodes of air pollution that had been experienced in London, Donora, and Meuse Valley ( Nathanson & Schneider, 2018). The pollution was greatly influenced by the invention of automobiles which used gasoline. Many people died while others fell ill as a result of temperature inversions when dense smog that saturated the air. Air pollution was later recognized as a global affair in the mid-1980s with the discovery that chemical contaminants destroyed the ozone layer. International mitigation measures have, therefore, been taken especially in the 21st Century.

The atmosphere is made up of five layers which extend to around 160km above the earth's surface (Nathanson & Schneider, 2018). The troposphere is the lowest atmospheric layer which is 12km deep and contains 80% of the total air mass. The troposphere is where clouds form, weather patterns develop, air pollution occurs, and oxygen-dependent life survives. The second layer is the stratosphere which rises to 50km. This is a stable layer, although it has a lower air density than troposphere. The layer contains an ozone layer which protects us from toxic ultraviolet radiations from the sun. The mesosphere is the third layer and it extends to about 85km. The fourth layer is the ionosphere which occurs from an altitude of 48km. The last layer is the thermosphere and it starts at an altitude of 100km. The mesosphere, ionosphere, and the thermosphere are not affected by air pollution.

The movement of air determines how air pollutants are dispersed or diluted in the troposphere (Nathanson & Schneider, 2018). They can either be vertically or horizontally dispersed. Horizontal dispersion relies on the speed and direction of the wind. A 'windrose' is a graph in which data on wind velocity is plotted. The graph is used in studying prevailing winds, therefore, aids in determining where industries or power plants should be established to reduce the impacts of air pollution.

According to Nathanson and Schneider (2018), there are three types of temperature inversions. Frontal inversions occur when hot air masses exceed cold air masses at high altitudes. Subsidence inversions form at high altitudes and occur when great air masses fall on a community. The inversion can last for several days or weeks, forming a cover which contains air pollutants. Radiation inversions result from radiation when the ground cools rapidly especially at night, during winter. The low temperatures led to trapping of air pollutants on the ground and are released when conditions become warmer. Both subsidence and radiation inversions affect air quality since they result in fumigation conditions.

Nitrogen oxide, ozone, and particulate are considered as criteria pollutants under the NAAQS (Nathanson & Schneider, 2018). This is because they are part of the greenhouse gases which contribute to global warming. Smoke is a particulate whose size ranges from 0.1 to 1m. The three pollutants are, hence, significant as they cause health problems, damage to crops, buildings and other exposed materials.

There are three international initiatives aimed at curbing global warming (Nathanson & Schneider, 2018). The first is the 1992 treaty signed during the Earth Summit in Rio de Janeiro which obliged industrialized countries to regulate the emission of greenhouse gases. Secondly is the 1995 Berlin mandate where 120 countries conferred to come up with long-lasting timetables on how to reduce greenhouse emissions. Lastly is the 1997 Kyoto protocol where specific targets and timetables were set to regulate worldwide greenhouse emissions. Countries were, therefore, required to ratify the agreement to facilitate its implementation.

Technologies have been invented to improve the quality of indoor air (Nathanson & Schneider, 2018). For instance, improvements in the designs and operations of buildings have been done to improve indoor air quality. Secondly, the application of "green" building maintenance and construction practices is used to reduce the exposure to air pollutants. Lastly, reducing the sources of pollutants and adequate ventilation has proved to be very effective in improving the quality of indoor air.

The concentration of air pollutants can be expressed in milligrams or micrograms per cubic meter, or as parts per million or billion (Nathanson & Schneider, 2018). If the concentration of ozone in a neighborhood is 90ppb, the concentration in micrograms per cubic meter at 2500 C and 1 atmosphere pressure is calculated as follows: mg/m3= (273*0.09*48*1) (22.4*298) = 0.1766778mg/m3 which is 176.6778g/m3.

There are various strategies used to control air pollution (Nathanson & Schneider, 2018). The first is to substitute the type of fuel used, for example, using hydroelectric, geothermal, and solar energy. The second is the proper location of industrial facilities and power plants to reduce the exposure of people to pollutants. The last technique involves the utilization of proper maintenance and operation practices to reduce air pollution.

An electrostatic precipitator is a device that is used to filter fine particles such as smoke and dust from flowing air (Nathanson & Schneider, 2018). The device contains two electrodes, where the first is negatively charged and the latter positively charged. As air moves from the first electrode, the particles become negatively charged and are then attracted to the positively charged electrode. Clean air, therefore, comes out at the other end.

Conclusion

In conclusion, air pollution is a global problem that requires proper attention. Air pollution originates from the discovery of fire and has persisted up to the 21st Century. Various initiatives have been formulated with the aim of controlling air pollution. These include measures to regulate the emission of greenhouse gases which cause global warming, and air control techniques.

Noise Pollution and Control

Noise is one of the effects of the modern lifestyle and is a form of pollution (Nathanson & Schneider, 2018). Laws and policies have been formulated on the control of noise pollution. This essay, therefore, seeks to discuss issues related to noise pollution and its control.

Noise is a form of energy and is transmitted through media as sound waves. When sound waves travel through air, they are seen as pulses of air pressure (Nathanson & Schneider, 2018). Wavelength refers to the distance between pressure peaks, while frequency is the number of wavelengths that pass through a fixed point in 1 second. The wavelength of a sound traveling through steel at 5000m/s and a frequency of 400Hz is 12.5m. This is calculated as follows: wavelength (l) = speed (m/s) frequency (cycle/sec), i.e. 5000m/s 400 Hz= 12.5m.

Decibels are measurement units used in the decibel scale. The decibel scale is a logarithmic relationship which does not directly use pressure in measuring sound waves (Nathanson & Schneider, 2018). A decibel (dB) is not an actual physical quality but is rather a ratio between two pressures. The logarithm, thus, converts the range of the ratios into simple numbers. Decibels express the magnitude of a sound in a Sound Pressure Level (SPL). The threshold of hearing (0.0002bar) is the reference pressure which is used for P0. The decibel scale, therefore, is useful in measuring the levels of noise.

Sound level meters are electronic gadgets that are used to measure noise. The following are specifications of the 'Pyle PSPL25 Digital Handheld Sound Level Meter' (Amazon.com). Firstly, it has a maximum 'Hold and Data Hold Function' with a frequency weighting of A and C Type, when stored at a humidity of 10 to 75% RH. Secondly, it has an 'Auto power off -time weighting, with a 9V battery. Thirdly, there is a level range of; low - 30-100dB and high - 60-130dB at an operation temperature of 0 to 40oC. Fourthly, its dimensions are 9.06'' H x 2.17'' W x 2.17'' D, with an accuracy of +/- 1.5dB (ref. 94dB @ 1 kHz). Finally, the cost of the handheld sound meter is $41.39.

Noise can essentially be controlled using four basic techniques (Nathanson & Schneider, 2018). The first is referred involves the protection of the recipient from excess noise by using ear muffs or ear plugs. These are useful in industrial or construction sites. The second is a passive measure which involves increasing the distance from the noise source to the recipient. The third technique is the use of noise barriers in the sound wave's path which absorb and reflect sound energy, hence, reducing sound levels. The last is an active technique which involves the reduction of sound at its source, for example, muffling vehicles and machines.

According to Nathanson and Schneider (2018), noise from transportation activities can be reduced through the following methods. One involves apt planning and designing of highways, for instance, reducing traffic volume and having low-speed limits near residential areas. Secondly, noise can be reduced through the construction of noise barriers on the highway such as concrete or masonry walls, and sloping earthen berms. Finally, aircraft noise can be mitigated through the advancement of engines and airframe designs, as well as controlling the flight patterns.

Conclusion

In conclusion, noise is a form of pollution which results from the modern lifestyle. Noise is transmitted in form of sound waves and they appear as pulses of air pressure when traveling through the air. Sound waves are measured using a decibel scale using decibel units. Sound level meters are used to measure noise. Noise pollution has negative effects; therefore, various techniques have been invented to control noise.

References

Amazon.com. https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=hand-held+sound+level+meter

Nathanson, J.A. & Schneider, R.A. (2015). Basic environmental technology: Water supply, waste management, and pollution control (6th Ed). Upper Saddle River, NJ: Pearson.