Introduction
Many times people wake up to find the surrounding covered with a mass of water droplets which impairs human visibility and to a certain extent forms due on objects and surfaces. Among the causes of this kind of situation is fog. Fog is a low-lying condensed water droplet from the air which are heavy enough to lie near the earth’s surface. Fog is denser than mist which has the same characteristics and can reduce visibility to less than a kilometer, as opposed to mist where visibility is clear further than a kilometer. Though they are less the same, fog and cloud can be differentiated due to the place of hanging in that clouds hang up high in the sky while fog hangs near the earth’s surface (Jacobson, 2005).
Fog is formed when there is a difference in temperature between two air masses and mostly when the cold air mass is trapped below a warmer air mass and relative humidity is or nears 100%. When relative humidity is 100%, it means that additional water vapor to the atmosphere cannot be handled and any addition of water vapor causes the formation of fog. Fog can also be formed as a result of a warm air current passing over a relatively cold surface area e.g. snow or ice. The density of fog to a greater extent depends on the height above sea level of the inversion boundary (Ackerman, S. Ackerman & Knox, 2011). Depending on where and how the cooling effect takes place, the appearance and lasting duration of fog are affected and using this scientists have been able to categorize fog into various groups namely steaming fog, radiation fog, freezing fog, ice fog, advection fog, evaporation fog, hail fog and sea fog.
Preference Places
Fog frequents areas, where warm currents and cold currents meet since here, is where the temperature difference usually occurs. The meeting of the warm Gulf Stream and the north cold Labrador Current makes the Grand Banks of Newfoundland the world’s foggiest place. Some other places in the world where fog occurrence is common to include California, Argentina, Newfoundland and Point Reyes. Fog also occurs in other relatively warmer areas which include; Tiber valleys in Italy, the Swiss plateau coastal Chile and coastal Namibia (Smithson, Addison & Atkinson, 2002).
Chemistry Explanation
It is the temperature fluctuations that cause the formation of fog when the difference between outdoor temperature and due point reduces significantly, becoming equal or nearly equal then fog forms. Because of this, the air mass becomes saturated and unable to contain additional moisture leading to the formation of water droplets (Moller, 2010). Dew point is the given level of temperature to which water vapor should be subjected in order to turn into a liquid. If dew point and temperature remain equal for long or temperature reduces while dew point remains constant the fog lasts for long before disappearing. If the temperature is equal or lower than the dew point and the temperature is increasing, the fog lasts for a shorter period of time sometimes, fog disappearing significantly fast depending on how fast the temperature is increasing (Moller, 2010). It is also important to note that the dew point depends on pressure which has to remain constant for the dew point to be measured at a specific level. On the other hand, if both temperature and pressure decrease, the dew point will decrease hence relative humidity will increase and this will cause fog.
Environmental Hazards
Research has shown that fog water contains a lot of mineral irons like H+, NH4+, NO3–, and SO42- which have different consequences to the environment. Also due to the fact that fog formation takes place close to the earth’s surface, its water is contaminated with the products from various emissions that take place daily making these water acidic and unfit for living organisms (Cotton, Bryan & Heever, 2010). Fog reduces visibility considerably impairing transport and leading to various problems including flight delays, airplane crashes, road accidents and shipwrecks. Fog also contains aerosols which due to decreased insulation harm agriculture productivity causing economic impacts. Black carbon which has been found in large quantities in fog is a cause of high radiative forcing and causes atmospheric warming (Guttepe, 2007).
Respiration and Gaseous Exchange Effect
Due to much humidity associated with fog, it has been noted that patients with asthma cough when they inhale fog. Fog causes diffuse radiation which enhances gaseous exchange by increasing carbon uptake. It has also been found through research that foggy conditions lead to an increase In particulates’ load which eventually causes rising in depression, respiratory and heart ailments (Cotton & Pielke, 2007). At the low temperatures where fog forms oxygen concentration is a high and decreased rate of metabolism reduces the respiration in animals.
Conclusion
Fog formation is an inevitable natural phenomenon that has negative environmental impacts on our community and what we can only do is to learn how to be prepared for it. Though fog is associated with many negative effects man has used it for beneficial purposes, for example, extraction of moisture in places where groundwater and rainwater are inadequate among other positive effects. It causes massive economical losses and should therefore be given enough attention in studying it and coming up with ways of coping with it.
References
Ackerman, Ackerman, S., & Knox, J. (2011). Meteorology. Sudbury: Jones & Bartlett Publishers.
Cotton, R. W., Bryan, G., & Heever, V. S. (2010). Storm and Cloud Dynamics. Waltharn: Academic press.
Cotton, R. W., & Pielke, A. R. (2007). Human Impacts on Weather and Climate. New York: Cambridge University Press.
Guttepe, I. (2007). Fog and Boundary Layer Clouds: Fog Visibility and Forecasting. New York: Springer
Jacobson, Z. M. (2005). Fundamentals of Atmospheric Modeling. New York: Cambridge University Press.
Moller, D. (2010). Chemistry of the Climate System. Berlin: Walter de Gruyter.
Smithson, P., Addison K., & Atkinson, K. (2002). Fundamentals of Physical Environment. New York: Routledge.