Air pollution is a major problem of recent decades, which has a serious toxicological impact on human health and the environment. The sources of pollution vary from small unit of cigarettes and natural sources such as volcanic activities to large volume of emission from motor engines of automobiles and industrial activities. Long-term effects of air pollution on the onset of diseases such as respiratory infections and inflammations, cardiovascular dysfunctions, and cancer is widely accepted hence, air pollution is linked with millions of death globally each year. A recent study has revealed the association between male infertility and air pollution. Air pollution has now emerged in developing countries as a result of industrial activities and also increase the quantity of emission sources such as inappropriate vehicles. About 4.3 million people die from household air pollution and 3.7 million from ambient air pollution, most of whom (3.3 and 2.6 million, respectively) live in Asia. Ahvaz is the most air polluted city in the world with microdust blowing in from neighboring countries, and particulate levels three times that of Beijing, and nearly 13 times that of London. Air pollution is of great importance to describe the problem, particularly its toxic effects on human health and provide recommendations as a basis for environmental guidelines and standard protocols in the field of air pollution.
The 2016 Environmental Performance Index (EPI) ranked India 141 out of 180 countries surveyed. EPI is unique in its approach because it incorporates many high-priority environmental issues, including resource consumption, depletion of environmental assets, pollution, and species loss among other important topics. The EPI typically ranks countries on performance indicators tracked across policy categories that include both environmental public health (protection of human health) and ecosystem vitality (protection of ecosystems). Within these two policy objectives, the EPI scores national performance in nine issue areas comprised of about 19 indicators. Environment health, being the first policy objective, is given 50% weightage and it comprises 3 categories viz. health impacts, air quality and water and sanitation, each given 33% weightage in the score within; whereas ecosystem vitality, being the second policy objective, is again given 50% and it comprises 6 categories viz. water resources (25%), agriculture (10%), forests (10%), fisheries (5%), biodiversity & habitat (25%) and climate & energy (25%).
Toxicology of Air Pollution
Effects of air pollutants on living organism will not only be limited to the human and animal health but also include the whole environment. Different geographical conditions, global climate changes, and the environmental variations affect the human health and the environment including the animal life.
Ecologically, air pollution can cause serious environmental damages to the groundwater, soil, and air. It is also a serious threat to the diversity of life. Studies on the relationship between air pollution and reducing species diversity clearly show the detrimental effects of environmental contaminants on the extinction of animals and plants species. Air suspended toxicants may also cause reproductive effects in animals. Acid rain, temperature inversion, and global climate changes due to the emissions of greenhouse gasses to the atmosphere are other major ecological impacts of air pollution.
Air pollutants and their toxicities
Every material in the air which could affect human health or have a profound impact on the environment is defined as air pollutants. According to the World Health Organization (WHO), particle pollution, ground-level O3, CO, sulfur oxides, nitrogen oxides, and lead (Pb) are the six major air pollutants which harm human health and also the ecosystem. There are many pollutants of suspended materials such as dust, fumes, smokes, mists, gaseous pollutants, hydrocarbons, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and halogen derivatives in the air which at the high concentrations cause vulnerability to many diseases including different types of cancers.
Other air pollutants
Other major air pollutants that are classified as carcinogen and mutagen compounds and are thought to be responsible for incidence and progression of cancer in human include VOCs such as benzene, toluene, ethylbenzene, and xylene, PAHs such as acenaphthene, acenaphthylene, anthracene, and benzopyrene, and other organic pollutants such as dioxins, which are unwanted chemical pollutants that almost totally produced by industrial processes and human activity.
How Air Pollution Damages the Body
While air pollution’s link to respiratory disease may seem obvious, its relationship to heart, brain and fetal health is less so. There are at least two possible mechanisms by which air pollution can harm parts of the body besides the nasal cavity and lungs, said Anthony Gerber, a pulmonologist at National Jewish Health in Denver. The first has to do with inflammation, which is the body’s way of repairing itself after an injury or illness. When the toxic soup of chemical particles and liquid droplets emitted by cars, power plants, fires and factories known as particulate matter is inhaled, the microscopic toxic dust can irritate nasal passages and result in an allergic-type response to the pollution, with symptoms like coughing and a runny nose. Scientists believe that as the particles make their way deeper into the airways and into the lungs, the body may mistake it for an infection, triggering an inflammatory response. “When you have a bad head cold, you feel sick everywhere and your muscles might ache,” Gerber said. “The same thing can happen when you breathe in pollution.” Scientists also suspect that some toxic particles can escape the lungs and enter the bloodstream.
Effects on Human Health
Some environmental poisons can cause acute illness and even death. Others may be harmful, but the disease may take years or even decades to appear. Air pollution mainly affects the respiratory system. Bronchitis, emphysema, asthma and lung cancer are some of the chronic diseases caused due to exposure to polluted air. It is feared that lung cancer is caused mainly due to polluted air because carcinogens are found in it. Its mortality rate is higher in urban areas. Sulfur dioxide is the most serious and widespread air pollutant. Its lower concentration is a cause of spasms in the smooth muscle of bronchioles and its higher concentration induces increased mucus production. Sulfur dioxide is also considered to cause cough, shortness of breath, spasm of the larynx and acute irritation to the membranes of the eyes. It also acts as an allergenic agent. When it reacts with some compounds, sulfuric acid is formed which may damage lungs. Carbon monoxide often affects the oxygen carrying capacity of blood. Nitric oxide is reported to be a pulmonary irritant and its excess concentration may cause pulmonary haemorrhage. Hydrogen sulfide is also toxic. Lead emitted from automobile exhausts is a cumulative poison and is dangerous particularly to children and may cause brain damage. The particulate pollutants such as asbestos, silica, carbon, beryllium, lead, etc., are capable of exerting a noxious (fibrotic) local action in the interstitial areas of the lungs. Radioactive elements are also harmful to man and other living organisms. As described earlier, smog has a killer effect, which is also the result of air pollution. The death toll by smog varies from few persons to thousands.
By – HOD – Dr. Abhishek Bahuguna
Department of Horticulture
Magazine (YouthRainBow)- Uttaranchal (P.G.) College Of Bio-Medical Sciences & Hospital
Uttaranchal (P.G.) College Of Bio-Medical Sciences & Hospital
Uttaranchal College of Education
College Of Nursing UCBMSH