Health Hazard of Air Pollution
Air pollution causes irreversible harm to the human body. It interferes with cellular activity and induces abnormal behavior in cells. According to the World Health Organization (WHO), air pollution is a leading cause of disease and death worldwide.
A report released by the WHO stated that an estimated 4.2 million people died in 2016 due to ambient air pollution related health complications. Another 3.8 million died during the same year due to indoor air pollution caused by the use of unsafe cooking fuel like firewood, dung cakes, coal and kerosene.
In India, an estimated 12.4 lakh people perished in 2017 due to the effects of air pollution said a study published by the Indian Council of Medical Research (ICMR), Public Health Foundation of India (PHFI), Ministry of Health and Family Welfare and The Lancet. Of this, 6.7 lakh fatalities were due to ambient particulate matter air pollution while 4.8 lakh fatalities were on account of indoor air pollution.
A 2017 WHO report revealed that 14 of the 15 most polluted cities in the world based on PM 2.5 pollution were Indian cities with Kanpur taking the infamous lead followed by Faridabad, Varanasi, Gaya, Patna and Delhi, in that order.
Air pollution chiefly affects the respiratory, cardiovascular, reproductive, ophthalmologic, endocrine, hematologic, dermatologic, immunologic and neuropsychiatric systems. It is responsible for heart disease, lowered lung activity, chronic obstructive pulmonary disease, asthma and bronchitis.
In children, it causes acute respiratory infections, diabetes and neurological disorders. In pregnant women, it causes anomalies in fetal development and induces pre-term birth.
According to the WHO website:
“Worldwide ambient air pollution accounts for:
- 29% of all deaths and disease from lung cancer
- 17% of all deaths and disease from acute lower respiratory infection
- 24% of all deaths from stroke
- 25% of all deaths and disease from ischaemic heart disease
- 43% of all deaths and disease from chronic obstructive pulmonary disease.”
The major air pollutants are particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOC), aerosols, lead, chlorofluorocarbons (CFC), hydrocarbons, vanadium, cadmium, copper, radon and nickel.
Particulate matter consists of fine solid particles suspended in the air. They have diameters of 10-2.5 micron and even less. They enter our body through breathing and cause extensive harm to the lungs, blood and heart. Tropospheric ozone causes coughing, wheezing, inflammation of lung tissue and reduced lung activity. It also aggravates bronchitis, asthma and emphysema.
Oxides of nitrogen react with other air pollutants and form acid rain and ground-level ozone, both of which are injurious to health and the environment. It causes nausea, bronchitis and indigestion, among other things. Inhaling air rich in sulphur dioxide causes shortness of breath, sneezing, coughing and irritation of the respiratory tract.
Diseases caused by air pollution
Before we start, it is important to bear in mind that the extent of harm depends on the nature of the pollutant(s), the duration and intensity of exposure, and the health of the person. Let us now analyze the diseases caused by air pollution.
As most of the air pollutants enter our body through the nose and mouth, the respiratory tract takes the biggest hit. It is the first line of battle where all the attack happens. Exposure to polluted air causes coughing, sneezing, wheezing, shortness of breath, common cold, nausea, headache, giddiness, and irritation of the eyes, nose and throat.
Prolonged exposure can cause debilitating lung disease, lung scars, inflammation of the tissue lining the lungs, and in severe cases, lung cancer.
Asthma is a condition in which the tissues around the airways (bronchospasm) of a person become inflamed and swell up producing excess mucus and narrowing the air path. This makes it difficult for the person to breathe normally. Asthma is triggered by smoke, pollen, dust mites, pet dander, fungal spores and fine respirable particulate matter.
COPD is a group of lung diseases that impede normal breathing. The primary cause of COPD is tobacco smoke which is a deadly type of particulate matter. You don’t need to be a smoker to be afflicted by COPD. Secondhand smoke is as bad, and can prevent you from breathing comfortably. In rural areas, a major reason behind COPD is burning of firewood, biomass and coal for cooking and heating purposes. Toxic chemical fumes and dust also contribute to COPD.
COPD eventually leads to an irreversible decline in lung function. Emphysema and chronic bronchitis are two very common COPDs.
It is a condition in which the alveoli or air sacs at the end of the smallest air passages (bronchioles) of the lungs are damaged due to excessive exposure to cigarette smoke. As a result, the body does not get the oxygen it needs and suffers various side effects.
It is a type of COPD characterized by the inflammation of the bronchial tube lining and production of mucus. It leads to constriction of the air path and induces chronic coughing.
Cystic fibrosis is a life-threatening genetic disorder that damages the lungs and the digestive system. It affects the cells that produce mucus, sweat and digestive juices. Air polluted with particulates and ozone has been found to exacerbate cystic fibrosis. It accelerates bacterial build up in the lungs resulting in lung infection. A recent study indicates that air pollution increases the risk of young children with cystic fibrosis contracting the methicillin-resistant bacteria Staphylococcus aureus, or MRSA.
Wheezing is most common in small children. It is characterized by a high-pitched whistle-like sound during exhalation. Wheezing happens due to a lower respiratory infection caused by the respiratory syncytial virus. It is consequence of exposure to polluted air, pollen, bugs, and food/drug allergens.
Coal Worker’s Pneumoconiosis (CWP)
CWP is also known as black lung disease. It is mainly suffered by coal miners and is caused by the deposition of fine coal dust in the lungs. It is a result of long-term exposure to coal dust and it induces inflammation, fibrosis and necrosis.
Silicosis is similar to CWP in that it is caused by inhalation of crystalline silica dust. It is an occupational lung disease suffered by miners, masons, quarry workers, grinders and potters who work in high-pollution environments. Fine silica acts like a blade on the lungs. It causes small cuts which scars the lungs and makes them susceptible to diseases.
Pneumonia is a lung infection characterized by inflammation of the alveoli (air sacs) in the lungs. It is triggered when a person inhales air polluted with certain kinds of bacteria, virus, fungi or other parasites. As the disease progresses, the alveoli fill up with fluid and the lungs swell up. Contaminated air and tobacco smoke is one of the biggest reasons for the spread of pneumonia. People already suffering from COPD, asthma, cystic fibrosis and other lung conditions are more vulnerable to pneumonia.
Air pollution is a major cause of heart disease and stroke. It induces progressive degeneration and inflammation of heart tissue. It ages the blood vessels prematurely and causes high blood pressure. Air pollution is especially fatal for people already suffering from heart conditions.
Air contaminants cause the plaque in blood vessels to rupture, triggering a cardiac arrest. People with diabetes, hypertension and obesity are more at risk of developing inflammatory reactions due to air pollution.
Air filled with nitrogen dioxide fumes has been linked to left and right ventricular hypertrophy. Studies have also shown that cities with high smog concentrations have higher rates of hospitalization and death due to heart conditions.
Fine particulate matter (PM 2.5) and ultra-fine particulate matter (PM 0.1) are lethal for the heart. According to the National Center for Biotechnology Information, USA, PM 2.5 and PM 0.1 transgress terminal alveoli and “trigger coagulation, thrombosis, increased heart rate and reduced heart rate variability, endothelial dysfunction, arterial vasoconstriction, apoptosis, and hypertension.
In chronic exposures these alterations favor the development and progression of atherosclerosis and possibly of hypertension in the long term, and in the short term acute exposures contribute to plaque instability, affect various traditional risk factors and trigger acute cardiovascular events (myocardial ischemia and infarction, stroke, heart failure, arrhythmias, and sudden death), particularly in high-risk subjects.”
In 2013, the International Agency for Research on Cancer (IARC), a WHO subsidiary, classified particulate matter with diameters of 10-2.5 micron and smaller as carcinogens. It stated that air pollution is directly linked to cancer of the lungs and urinary bladder.
Prolonged exposure to particulate matter has been found to contribute to liver, pancreatic and breast cancers. Traffic-related air pollution and inhalation of benzene and nitrogen dioxide vapors have been associated with childhood leukemia, a type of blood cancer that mostly afflicts children under the age of 15.
Studies have also found a correlation between exposure to asbestos and mesothelioma, a rare kind of lung cancer that affects the lining of the lungs, heart or abdomen.
Inhaling polluted air impacts the central nervous system. It induces headache, nausea, fatigue and lack of concentration. It also triggers neurological anomalies and psychiatric disorders. In infants and small children, it has been found to result in mental neurological development and low IQ. In expecting mothers, it has been linked to premature deliveries.
Psychiatric disorders include aggression, age-inappropriate behavior, antisocial conduct and propensity to criminal activity. A study conducted in the Greater Los Angeles area found a connection between air pollution and teen delinquent behavior. It revealed that air pollution caused inflammation of the brain and neural systems which in turn triggered antisocial activity amongst youngsters.
Studies have also found a relation between air pollution and Alzheimer’s and Parkinson’s diseases. Furthermore, in large metropolises, high levels of outdoor air pollution have been found to be a definitive cause of anxiety and aggression.
Autism and other birth defects
Exposure to air with high levels of poisonous heavy metals and polycyclic aromatic hydrocarbons has been found to lower the quality of sperm in men. In pregnant women, polluted air affects both the mother and the unborn child. In fact its harmful effects start right from the moment of conception and continue well past delivery.
Autism is the most common birth defect induced by air pollution. A Harvard study found that sustained exposure to extreme levels of particulate matter pollution during pregnancy made the fetus twice as likely to develop autism. The findings of the study were also corroborated by the US National Institute of Health which found a “compelling causal connection between air pollution and autism spectrum disorders”.
Ongoing research has also established a correlation between air pollution and low immunity in newborns. They state that early exposure to polluted air makes infants more prone to common cold, breathing problems and allergies.
Air pollution has damaging effects on the ocular surface. It causes irritation, burning, stinging, tearing and general discomfort in the eyes. High concentration of oxides of nitrogen in the air has been linked to conjunctivitis while particulate matter pollution has been found to induce dry eye syndrome.
Household air pollution resulting from combustion of firewood, coal and kerosene is especially harmful for women. For instance, inhalation of kerosene fumes has been associated with nuclear cataract in rural women in India.
A direct relation has also been found between tobacco smoke and thyroid eye disease. It also increases the risk of ophthalmopathy in Grave’s disease. In small children and developing fetuses, secondhand tobacco smoke is believed to cause strabismus.
Pollution has a grave impact on our skin as it is the first line of defense against foreign elements like air pollutants. It acts as a physical, chemical and immunological barrier against the outside environment. Prolonged exposure to polluted air can cause imbalances in the skin tissue as airborne particles are constantly absorbed through the skin, hair follicles and sebaceous glands.
Pollution can accelerate skin aging, trigger allergic reactions, lower skin elasticity and cause wrinkles and pigmentation. Common air pollution-related dermatological disorders include atopic dermatitis, eczema and psoriasis. Tobacco smoke and polyaromatic hydrocarbons have been associated with premature aging of the skin, acne, pigmentation, and in worse cases, skin cancer. VOCs have been linked to atopic dermatitis.
Certain airborne volatile and semi-volatile chemical compounds interfere with the functioning of the endocrine system. These chemicals are known as endocrine disrupting chemicals (EDC) and they cause hormonal anomalies in the body.
Exposure to EDCs adversely affects on the reproductive health of a person. They interfere with estrogens and androgens activity and cause hormonal imbalance. EDCs also impact thyroid, immunological and adrenocortical activity. They impede fetal development and lactation in young mothers.
Immune system disorders
People who live in high-pollution areas are prone to immune system dysfunction. Polluted air causes a spike in the serum levels of the immunoglobulin and triggers neuroinflammation, an altered brain innate immune response.
A joint study by Stanford University and the University of California, Berkeley, found that air pollution hindered the function of regulatory T cells (Treg) of the immune system. Reduced T cell function was found to aggravate asthma in young children and lower lung capacity.
Treg cells prevent the body’s immune system from acting on non-pathogenic particles associated with asthma and allergies. Owing to lowered Treg function, the cells fail to prevent the inflammatory responses triggered during an asthmatic attack.
Traffic-related air pollution has been associated with abdominal cramps and diarrhea. A study conducted in Hong Kong on elderly people aged 65 years and older revealed that acute exposure to nitrogen dioxide-infused air increases the risk of upper gastrointestinal bleeding from peptic ulcers. Other studies have found a correlation between inflammatory bowel disease and urban air pollution.
Government initiatives to tackle air pollution in India
The Indian government has taken several steps to curb air pollution in the country. In early 2018 the central government launched the National Clean Air Program (NCAP), a comprehensive 20-point plan to reduce air pollution by 50% in the next 5 years.
The Rs 637-crore program has a detailed list of responsibilities for both the centre and the state governments. It puts the onus of controlling pollution on the state while the centre plays a supporting role in helping the states achieve their goals.
The program lays emphasis on scientific collection and scrutiny of data from credible sources. It introduces rural air quality monitoring and formulates a new institutional framework for fighting air pollution both at the central and state levels.
Here are the key points of the NCAP
- The states are required to draw up their own Clean Air Programs.
- The states have to meet the prescribed annual average ambient air quality standards.
- 50 air quality monitoring stations to be set up in rural areas across the country.
- Manual air quality monitoring stations to be increased from 691 to 1000.
- Source apportionment studies to be sanctioned in 94 cities to study the sources of pollution and their contribution.
- An Air Information Center will be established for data analysis, interpretation and policy making.
- PM 2.5 to be monitored all over the country.
- Extensive aforestation drive to be flagged off.
- Air Quality Management Plan to be launched in 100 cities.
- A new special body to be set up to manage a 3-tier system of data collection, archiving and analysis.
- The Central Pollution Control Board will spearhead research into alternative means of monitoring ambient air quality.
- An Apex Committee under the Environment Ministry will oversee the activities. A Steering Committee under the Secretary of Environment and a Monitoring Committee under the Joint Secretary will also be set up.
To combat poor air quality, the central government recently unveiled the Air Quality Early Warning System. It was developed jointly by the Ministry of Earth Sciences and experts from USA and Finland. The new system is designed to alert the authorities about a drop in air quality 3 days in advance so that necessary action can be taken on time. The system also provides projections of air quality in different parts of the country.
In Delhi-NCR, an emergency plan called the Graded Response Action Plan has been brought into effect. It lays down specific regulatory actions for National Air Quality Index categories of Moderate, Poor, Very Poor and Severe. It also adds a new category called Severe+ or Emergency to the existing list.
For instance, if the ambient PM 2.5 or PM 10 level in Delhi dips to 300µg/m3 or 500 µg/m3 respectively, and stays at that level for 48 hours or more, the AQI will fall under Severe+ or Emergency, and that will immediately trigger the following regulatory actions:
- Entry of all trucks, except those carrying necessary goods, into Delhi will be stopped.
- All construction activity will be stopped.
- Odd-even scheme for private vehicles will be started.
- A Task Force will take necessary additional actions as required, such as temporarily closing schools.
The GRAP is overseen by the Environment Pollution (Prevention and Control) Authority, an organization established under the direction of the Supreme Court of India with the sole objective of reigning in air pollution in Delhi-NCR.
The GRAP has implemented more stringent rules to fight pollution in the capital. It has banned garbage burning, implemented pollution control measure in brick kilns, shut down many kilns, started mechanized sweeping of roads at regular intervals, tripled or quadrupled parking fees, increased bus and Metro services and started sprinkling water on the roads. The Badarpur thermal power plant has also been shut down to cut back on pollution in Delhi-NCR.
Air pollution poses a big health risk and calls for immediate corrective action from everyone concerned. Each of us needs to act responsibly and do what we can to keep our air safe. Unbridled pollution can have devastating effects on our planet and jeopardize our very existence. We need to take urgent steps to curb this menace before it’s too late.