In recent years, the cement industry is causing many environmental pollution problems across the globe. The pollutants of the cement industry produce the adverse impacts on all resources such as the air, water and land. The cement industry is among the top 17 most polluting industries listed by Central Pollution Control Board in India. During the last few decades, the emission of dust by products from cement factories has been increasing alarmingly due to expansion of more cement plants to meet the growing requirement of cement materials for construction of buildings and other infrastructures.
The cement industry causes gaseous air pollutants, many of which are mainly recognized as being the cause of injure to various types of vegetation for plants as well as animal habitats. However, relatively little is known and limited studies have been carried out on the direct effect of cement dust pollution on the growth of plants. The limestone mining and different stages of cement manufacture cause hazardous environmental impacts on air, water, soil, land, animals, humans as well as plant vegetation.
Environmental Impact Assessments were carried out in the areas around cement plants in Sirohi, Pali, Nagaur and Chittorgarh district, Rajasthan that showed the landscape had been entirely degraded due to dumping of overburden material, dust pollution and unclaimed mine pits. There has also been a constant increase in the number of quicklime manufacturing units, limestone and sandstone quarries in the surrounding areas thereby increasing dust pollution. Underclaimed mine pits have changed the aesthetic view of the area and degraded the land as well which causes a fall in the value of the location.
The prevailing and leading source of dust pollution in construction sites is of dusty facilities. Dust pollution refers to the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment. Thus, dealing with this problem is of utmost importance. It can be clearly understood from previous studies that the most important causes of dust production in a construction site are a combination of cement silos and dusty roads. Simply recognizable routes without any formal construction or maintenance such as unpaved roads can be the source of dust in most cases. Modern roads, which are normally smoothed and paved can be a solution for dust controlling as they do not spread dust to environment and can be a long-term solution for dust suppression.
Dust is also generated from cement factories. Everyday huge amounts of dust in the form of cement enters into the environment. This adversely affects living organisms that are surviving in and around that area. Increased concentration of cement dust pollutants causes invisible injuries like progressive decline in the physiological process such as photosynthetic ability and respiration rate of leaves which harm the overall development of the plants. Farmers have previously reported that cement dust pollutants block the stomata which leads to a reduction in yield of number of annual crops. Studies have also reported that due to cement dust, the productivity and concentration of chlorophyll in a number of crops decreases in the long-term.
In order to minimize the risk to human health caused by the cement industry, dust exposure from the factory is handled by managers who are necessarily required to put in place the latest technology, management systems and continuous online monitoring, and routinely implement the activities that facilitate adherence to the emission norms prescribed under the pollution control legislation of the country. In addition to implementing the technological and managerial measures to control dust and other emissions, it is also extremely important to provide adequate personal respiratory protective equipment for the chronically exposed people who face the dust on a regular basis. This is important as recent observations from studies have shown that cement contains many harmful elements which are hazardous to human health when exposed form use to user and its surrounding areas. Other studies show that cement contains 3-8% aluminium oxide, 0.5-0.6% iron oxide, 60-70% calcium oxide, 17-25% silicon oxide, 0.1- 4% magnesium oxide and 1-3% sulphur trioxide. These components directly influence the quality of soil in nearby areas as well. The pH of the cement-polluted soils has shown to be much more alkaline as compared to that of soil that is not polluted. Similar studies on cement dust pollution show elevated levels of soil pH not only in the cement factory and areas around the factory but also in places that cement is stored or used in the long term. Cement dust is a combination mixture of Ca, K, Si and Na which generally includes heavy metals like As, Al, Cd, Pb, Zn, Fe, and Cr. Majority of these elements in excess amounts are potentially harmful to the biotic and abiotic components of the environment and have shown adverse effects to bio diversity in the long-run.
We are now facing the problem that in relatively recent times, the total amount and complexity of toxic pollutants in the environment are increasing day by day not just from the cement industry but in totality of all commercial and industrial hubs in the country. These toxic pollutants play a massive role in degrading the quality of human, plant as well as animal life. Air pollution is a major problem faced by modern society and in recent years, the definition of air pollution has been broadened from the simple scope of dusty and dirty air. Research activities and various studies have been conducted to include analysis on the response of plants to a wide range of atmospheric chemicals that are regularly emitted from anthropogenic sources. Even though the problem is usually greater and often generated in cities and industrial hubs, air pollutants are now commonly found everywhere. Air pollutants are the sole reason for vegetation injury and crops yields losses. Injury and damages to the crops range from visible markings on the foliage, to reduced growth and yield, to premature death of the plant and much more.