Air Pollution: The Silent Killer

October 25, 2018, 8:47 pm

By Professor OAIleperuma,

Professor Emeritus,

University of Peradeniya

An average person consumes about 1 to 2 kg of food, 1 -2 liters of water and breathes about 10 000 liters of air a day. Although we are cautious about the hygienic aspects of food and water, do we ever care about the quality of the air we breathe? Breathing bad air causes a host of health problems such as asthma, bronchitis, chronic obstructive pulmonary disease (COPD) and lung cancer. More recent data suggest that in addition to these respiratory diseases, it is linked to various heart diseases and strokes, low birth weight, premature death and obesity. According to the World Health Organization (WHO), 92% of the world's inhabitants do not breathe clean air and about 8 million deaths a year are attributable to air pollution, including 4.3 million people resulting from indoor pollution and 3.7 million from outdoor air pollution. Worldwide, deaths related to air pollution have now overtaken water pollution as the leading cause of child deaths. In Sri Lanka, more than 45% of child admissions to hospitals are due to air pollution.

Air pollution results from the introduction into the atmosphere of chemicals, particles or biological material that are harmful or inconvenient to humans, other organisms . or damage natural vegetation and structures. An air pollutant can be defined as a substance present in a concentration sufficient to have an adverse effect on humans and other animals, vegetation or materials. In Sri Lanka, air pollution is mainly due to motor vehicle exhaust gases as well as to various industries, power plants and waste and biombad combustion.

The burning of fossil fuels produces a large amount of carbon monoxide and elemental carbon in the form of soot. , sulfur dioxide and nitrogen dioxide. Some, such as nitrogen and sulfur oxides, are harmful corrosive pollutants that destroy the protective layer of lung tissue, making them more vulnerable to attack by bacteria and viruses. They can cause the respiratory diseases mentioned above and we must also take into account the various heart problems of particularly elderly people likely to be affected by air pollution. Among these pollutants, sooty fine particles from vehicles are the most dangerous pollutant. Particles larger than 10 microns in diameter (one micron is one millionth of a meter) are filtered through the nose and upper respiratory tract, while particles smaller than 10 microns go straight into the lungs. This fraction is called PM10 fraction and even smaller particles whose diameter is less than 2.5 microns, PM 2.5 fraction are even more dangerous.

Air pollution is considered the leading cause of premature death in the world. Among the major global health risks, the pollution of outdoor air in the form of fine particles proves much more dangerous to public health than what we previously knew and contributes each year to more than 2 million premature deaths worldwide. What is more important is that a WHO global study ranks air pollution among the top 10 leading causes of death in the world, with 65% of all deaths due to air pollution in Asia. Just in 2010, particle pollution was the fourth leading risk factor for deaths in China, behind hypertension and smoking. In 2008 alone, more than half a million people died of air pollution in China and India. It is estimated that every year in the world, air pollution in urban areas will cause up to 3.6 million premature deaths, mainly in China and India.

In many Asian cities, fine particle levels – a major pollutant in terms of the human health impact exceeds the critical limit (as defined by WHO), particularly in densely populated, fast growing and less developed countries like China, India, Pakistan and Bangladesh. Even in small Asian cities such as Kathmandu, the particle level exceeds the mild standards recommended by WHO.

Air Pollution in Sri Lanka

According to statistics compiled by Professor Amal Kumarage of the University of Moratuwa, on average, 300,000 vehicles, including 15,000 buses, 10,000 trucks and 225,000 private vehicles enter the city of Colombo daily. There are 7.24 million vehicles in Sri Lanka, including 4.04 million motorcycles, with 1.14 million three-wheeled vehicles and 600,000 registered vehicles each year. The number of registered vehicles has almost quadrupled between 1990 and 2010, while the number of vehicles with three wheels and motorcycles has increased by 600% over the last twenty years. The absence of a high quality public transport system has pushed more than 50% of the workforce to use private vehicles to get to work. The average speed of vehicles in Colombo was 22 km / h in 2012 against 17 km / h. Vehicles in traffic jams produce more fine particles in the form of soot, which is detrimental to our health.

Last year, the WHO clbadified diesel fumes as Clbad 1 carcinogens, which means that they can certainly cause cancer. There are two kinds of poisons; acute and chronic. An example of acute poisoning resulting from air pollution may be the onset of asthma in asthmatics or the increase in the number of hospitalizations due to breathing difficulties. In 2005, WHO calculated that more than 20% of admissions to Lady Ridgeway Hospital due to asthma could be correlated with PM10 values ​​in the air. An earlier study from 2004 had correlated the increase in the number of asthmatic child admissions requiring nebulization in the same hospital on days when sulfur dioxide levels were high. Chronic poisons are those that act over a long period of time and are the true silent killers. The fine carbon particles of motor vehicles are the most dangerous type of pollutant. Not only do they damage the sensitive protective layer in the alveoli of the lungs, but they also contain many carcinogenic substances called polyaromatic hydrocarbons attached to fine particles. The accumulation of such compounds over several years can increase the rate of cancer, which is why exposure to exhaust gas from diesel engines can be considered a silent killer.

The WHO recently collaborated with the Coalition for Clean Air and Air (CCAC). ) have published air quality data for 3,000 cities worldwide and according to the data, 80% of the world's cities have exceeded safe air quality levels. This study shows that the levels of air pollution in the city of Colombo have multiplied by 3.6 compared to the safety threshold established by the WHO, 3.6 times, which is quite alarming compared to some other cities. In Colombo, recorded PM2.5 levels are 36 micrograms / m3, while for the country as a whole, this is 22 micrograms / m3. This study further indicates that 7792 people die each year from a disease related to air pollution and that the main disease caused by air pollution is ischemic heart disease. Another study compared the relative risk of heart attacks caused by different factors and staying in one hour of traffic is the main cause (relative risk 3.9), followed by a high cholesterol level (3). , 7), anger (3.1), smoking (2.8), diabetes (1.8) and physical inactivity (1.4).

In contrast, cities in developed countries are doing much better than PM2.5 levels, which are much lower. For example, the city of New York, where the number of vehicles is much higher, has an annual average of 9 micrograms / m3 and London, with a value of 15 micrograms / m3, slightly higher than the safety level, but far from values ​​of Colombo. The reason is that these western cities have better roads and transportation systems and discourage travel by car.

Indoor Air Pollution

People spend more time in indoor environments than in outdoor spaces. The air inside our homes can be polluted in several ways, among which: kitchen smoke, cigarette smoke, solvents, aerosols, formaldehyde (coming from adhesives in furniture), granite radon and burning mosquito coils and incense sticks inside houses. Of these, firewood burning in congested kitchens produces the pollutants most dangerous to our health. The burning of firewood produces a huge amount of carbon monoxide, which causes headaches due to a reduced oxygen supply to the brain, as well as many fine particles responsible for cardiovascular diseases (stroke, ischemic heart disease and respiratory). Mothers who spend their lives in congested kitchens develop lung cancer at an advanced stage of their lives after being continuously exposed to cooking smoke for years. Lung cancer is usually caused by excessive smoking and the occurrence of lung cancer in an elderly woman is most likely due to exposure to firewood smoke. In India, it has been found that 50% of health problems in women are due to exposure to cooking smoke, while 35% of diseases in children, which usually hang around their mothers, are also due to the pollution of the air. Men are free of such effects since they are in the living room or outside the house chatting with their friends.

Scientists in Sri Lanka conducted PM2.5 measurements inside 132 urban households using cleaner fuel such as LPG in Colombo. and found that these houses had an average concentration of 84.4 micrograms / m3 for PM2.5 in living space. Similar measures have been reported in houses burning firewood for cooking in urban areas, averaging 243.2 micrograms / m3 on average. These values ​​exceed the Sri Lankan standard of 25 micrograms / m3 for PM2.5, although the WHO standard is much stricter at 10 micrograms / m3.

The mosquito coils used by 2 billion people worldwide, who burn 12 billion reels each year. An anti-mosquito coil contains pyrethroids, coal dust / coconut pods, binders such as cow dung and resins. It is estimated that burning a mosquito net produces enough PM2.5 particles than 100 cigarettes and as many hydrocarbons produced by 50 cigarettes!

The burning of incense sticks produces about 20,000 micrograms / m3 of MP2,5 after a few hours the level is only 10 micrograms / m3. Anti-mosquito spirals and incense sticks produce polyaromatic hydrocarbons and benzene, which are known carcinogens. It is not recommended to burn them inside houses, especially in the presence of babies, because they breathe more air than adults in relation to their weight. For these reasons, it would be necessary to educate firewood kitchens in an open space outside the main house.

Pollution in Asian Cities

According to a report by the ADB, "Asian cities have made dismal progress over the last 10 years, with Asian cities and the 15 most polluted cities in the world a growing threat for human health 13. Asia's environment is so polluted and degraded that it poses a threat not only to the quality of life, but also to its economic prosperity ". Previously, Beijing was the most polluted city on Earth, but now, New Delhi has the dubious distinction of the most polluted city in the world. This is mainly due to the excessive amount of fine particles generated in the atmosphere by buses and cars and traffic jams. In some regions, in Delhi, especially at festivals like Diwali, PM2.5 levels reached 1,238. The WHO has stated that an exposure to annual average PM2.5 concentrations greater than or equal to at 35 is badociated with a 15% higher long-term mortality risk.

Air pollution and government inaction

The city of Colombo is lucky. have been located near the sea where pollutants disperse on flat ground. However, there are so many traffic jams throughout the day that release a huge amount of air pollutants into the atmosphere. Unfortunately, we have no way of knowing if we breathe clean air because the air quality control station located in Colombo Fort has been down since 2002 due to the lack of spare parts for measuring instruments of atmospheric pollutant levels. This is an excruciating excuse, knowing that millions are spent to import luxury cars for politicians and that the Ministry of Environment placed under the authority of the president can only find a few thousand to monitor the quality of the air. The equipment in question was obtained from World Bank funds in 1996 and ceased use in 2002.

Most countries have automated air quality control stations in all major cities. Most major cities have several stations of this type to represent different areas such as commercial and residential areas. Even smaller cities have at least one air quality monitoring station. These monitoring stations generally monitor five important air pollutants when a sample of ambient air is taken every 5 or 10 minutes. They are automatically sent via different instruments to determine pollutant levels and the data is automatically recorded for transmission to a central office responsible for air quality. The data obtained in this way are badyzed and the quality of the air is clbadified as good, moderate, unhealthy and dangerous. If the quality of the air is poor, appropriate pollution warnings are given to the general public on radio and television. People in developed countries are trained to take these warnings seriously and to take appropriate action. For example, if levels of sulfur dioxide and PM10 are high, it is advisable for asthmatics and people with heart problems to stay indoors. Even healthy people are encouraged to refrain from jogging and physical exercise.

The failure of the fight against air pollution harms the health of the population, but the government also costs millions of rupees for the treatment of those affected in hospitals. A sick population is a major obstacle to the development of a country due to the loss of national productivity, absenteeism in the workplace and the drain on health services spending. It is therefore essential that the government take action to combat air pollution as a priority.

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