Pollution and Its Adverse Effects

  Air pollution is a familiar environmental health hazard. We know what we’re looking at when brown haze settles over a city, exhaust billows across a busy highway, or a plume rises from a smokestack. Some air pollution is not seen, but its pungent smell alerts you. It is a major threat to global health and prosperity. Air pollution, in all forms, is responsible for more than  6.5 million deaths each year globally , a number that has increased over the past two decades. What Is Air Pollution? Air pollution is a mix of hazardous substances from both human-made and natural sources. Vehicle emissions, fuel oils and natural gas to heat homes, by-products of manufacturing and power generation, particularly coal-fueled power plants, and fumes from chemical production are the primary sources of human-made air pollution. Nature releases hazardous substances into the air, such as smoke from wildfires, which are often caused by people; ash and gases from volcanic eruptions; and gases, l...

Every other week we read of a new water pollution scandal, often after people fall sick, but sometimes because of large-scale fish die off or other adverse environmental impacts. Can we turn the tide of growing water pollution around? Human sources of water degradation include household and industrial waste, agricultural chemicals, and livestock waste, which all end up in water bodies and cause pollution if untreated or not managed appropriately.  As a result of insufficient action or plain inaction, today, approximately 1 in 8 or 650 million people live in areas where water quality risks are high due to elevated levels of biochemical oxygen demand (BOD), and 1/6 th  and 1/4 th  of the world’s population lives in river basins where water quality risks are high due to excessive nitrogen and phosphorous loadings. Levels of agricultural and domestic BOD, nitrogen and phosphorous are elevated or very high in China and India, parts of eastern and northern Africa; and...

Soil pollution  is defined as the presence of toxic chemicals (pollutants or contaminants) in soil, in high enough concentrations to pose a risk to human health and/or the ecosystem. In the case of contaminants which occur naturally in soil, even when their levels are not high enough to pose a risk, soil pollution is still said to occur if the levels of the contaminants in soil exceed the levels that should naturally be present, All soils, whether polluted or unpolluted, contain a variety of compounds (contaminants) which are naturally present. Such contaminants include metals, inorganic ions and salts (e.g. phosphates, carbonates, sulfates, nitrates), and many organic compounds (such as lipids, proteins, DNA, fatty acids, hydrocarbons, PAHs, alcohols, etc.). These compounds are mainly formed through soil microbial activity and decomposition of organisms (e.g., plants and animals). Additionally, various compounds get into the soil from the atmosphere, for instance with precipitatio...