The silent killer that stalks while you breathe | Sunday Observer

The silent killer that stalks while you breathe

Air pollution has trebled in Sri Lanka in recent years, due largely to the surge in vehicular traffic. The Sunday Observer spoke to Family Physician Health Ministry, Dr Ramya L. Premaratne to find out how this emerging phenomenon can affect the health of the Lankan population, and what steps the Health Ministry has taken to reduce this dangerous trend.


Q. Air pollution has been very much in the news lately, especially, after the Sri Lankan cricket team walked out of a test match in Delhi wearing pollution masks. Will Sri Lanka have a similar problem?

A. Yes. Air pollution is a serious environmental problem in Sri Lanka’s major cities such as, Colombo and Kandy.

Sri Lanka has undergone rapid industrialization. With the liberalization of the economy, energy consumption has increased and the number of vehicles has almost tripled in the last two decades, thereby increasing petrol consumption. Also, hydroelectricity that provided the country’s electricity needs has now been reduced and power generation from thermal power plants increased around 40%.

Q. What are the main air pollutants ?

A. Major air pollutants are:

Oxides of Carbon - carbon monoxide, carbon dioxide

Oxides of Nitrogen - nitric oxide, nitrogen oxide

Oxidies of Sulphur - Sulphur dioxide, sulphur trioxide

Particulates – dust, soot

Inorganic compounds – Lead

Photochemical smog – Ozone,

Peroxyacyl Nitrates Hydrocarbons - Benzo pyrene, Benzene

Q. What do you consider as the most dangerous of these pollutants?

A. Carbon monoxide and Carbon Dioxide are common poisons which may contaminate the air that we breathe.

Q. What are the health impacts of these toxic gases?

A. CO is a colourless, odorless gas, produced by fossil fuel, particularly, when combustion is not appropriate, as in burning coal and wood. Depending on CO concentration and the length of exposure, mild to severe poisoning may occur. Symptoms of CO poisoning may include headache, dizziness, weakness, nausea, vomiting, and finally loss of consciousness. The symptoms are similar to those of other illnesses, such as, food poisoning or viral infections.

In the case of sulfur dioxide which is a colourless, highly reactive gas, SO is very harmful to plant life, animal, and human health. People with lung disease, children, older people, and those exposed to SO are at a higher risk of skin and lung diseases. Residents of industrialized regions with SO even at lower concentrations (<1 ppm) might experience a high level of bronchitis.

The major health concerns associated with exposure to high concentrations of SO2 include respiratory irritation and dysfunction, and also aggravation of existing cardiovascular disease.

SO2 is predominantly absorbed in the upper airways. As a sensory irritant, it can cause bronchospasm and mucus secretion in humans. The penetration of SO2 into the lungs is greater during mouth breathing.

Nitrogen oxides may increase the risk of respiratory infections. They are mainly emitted from motor engines and are thus traffic-related air pollutants.

They are deep lung irritants that can induce pulmonary edema if inhaled at high levels. Epidemiologic studies demonstrate effects of NO on respiratory infection rates in children.

Coughing and wheezing are the most common complications of nitrogen oxides toxicity, but, eyes, nose or throat irritations, headache, dyspnea, chest pain, diaphoresis, fever, bronchospasm, and pulmonary edema may also occur.

Q. Other pollutants that cause adverse health impacts?

A. Ground-level ozone: this is found both, at ground level and in the upper regions of the atmosphere, called stratosphere. Ground-level ozone (GLO) is believed to have an association with an increased risk of respiratory diseases, particularly, asthma.

Lead (chemical symbol Pb) or plumb is a toxic heavy metal widely used in different industries. Pb pollution may result from both indoor and outdoor sources. It is emitted through motor engines, particularly with those using petrol containing Pb tetraethyl. Smelters and battery plants, as well as irrigation water wells and waste waters, are other emission sources.

Evaluation of the blood Pb level in traffic police officers shows that environmental pollution may be considered as a source of Pb exposure. Fetuses and children are highly susceptible to even low doses of Pb. Pb accumulates in the body in blood, bone, and soft tissue. Because it is not readily excreted, Pb can also affect the kidneys, liver, nervous system, and the other organs.

Q. Who are the high risk groups for this kind of poisoning?

A. Infants and children. Mental retardation, learning disabilities, impairment of memory, hyperactivity, and antisocial behaviours are the adverse effects of Pb in childhood. Therefore, it is important to reduce the Pb level of ambient air.

Pb exposure is often chronic, without obvious symptoms. It can affect different parts of the body including cardiovascular, renal, and reproductive systems, but the main target for Pb toxicity is the nervous system. Abdominal pain, anemia, aggression, constipation, headache, irritability, loss of concentration and memory, reduced sensations, and sleep disorders are the common symptoms of Pb poisoning. Exposure to Pb is manifested with numerous problems, such as, high blood pressure, infertility, digestive and renal dysfunctions, and muscle and joint pain.

Q. Can exposure to more pollution aggravate pre-existing conditions like asthma?

A. Pollutants such as ozone irritate people’s breathing, trigger asthma symptoms and cause lung and heart diseases; exposure to environmental tobacco smoke causes many severe respiratory health problems such as, asthma and lung cancer.

Q. The sharp rise of vehicular traffic in Sri Lanka is said to be one of the leading causes for toxic air pollution caused by petrol. According to recent research by the Motor Traffic Unit, vehicular traffic has doubled and tripled in the past decade and continues to do so with the addition of cars. Do you agree?

A.Yes. Aggressive and bold actions to control transport-related emissions should be undertaken to arrest serious air quality problems. The Government has prepared the General Guidelines for Vehicle Technology.

The setting of appropriate vehicle standards complemented by adequate fuel standards is important for emission reduction over time. Establishing regulatory measures to prevent the import of grossly polluting vehicles and establishing institutions for administering and enforcing vehicle emission standards with a primary task of identifying and removing gross polluting vehicles from the road, is a must.

Q. In what parts of the country do you find the highest concentration of air pollution ?

A. Cities. A recent study has shown that that the concentrations of CO and NO2 are high in Colombo and the concentrations of the five pollutants are comparatively large at Maharagama, on an average, indicating that the other cities may also be highly polluted as the commercial capital of Sri Lanka.

Q. Has the Health Ministry conducted a national survey on air pollution and its effects on human health, recently?

A. Yes. Air pollution is increasingly documented as a threat to public health in most developing countries. Evaluation of current air quality levels, regulatory standards and scientific literature on outdoor and indoor air pollution and health effects are important to identify the burden, develop and implement interventions and to fill knowledge gaps in Sri Lanka.

Sixteen studies investigated the association between exposure to ambient or indoor air pollution (IAP) and various health outcomes ranging from respiratory symptoms, low birth weight and lung cancers.

Q. What are the other environmental pollution and measures to be taken to reduce the adverse effects of air pollution?

A. An environment action plan to control air pollution is an urgent necessity. Our waterways are getting increasingly polluted by human sewage which has a direct impact on human health. There is a need to monitor pesticides in drinking water as they may have long term health effects such as, cancer.

There is also the possibility of food contamination through pesticides sprayed on vegetables and fruits close to the time of harvesting. Isolated instances of heavy metal pollution by Lead, Chromium, and Mercury have been reported.

Q. What about factories that dump their polluted waste into ground water which contaminate lakes, rivers, tanks where people bathe. I understand there are laws to prevent this but they are not properly implemented. Your comments?

A. The Pollution Prevention Act has established a national policy on this.

Q. The Health Ministry recently sought the support of the private sector to help instal air regulators at a few petrol sheds to measure air quality. Has there been a good feedback on this?

A. Yes. The data can be used for evaluating potential health risks.

The main reason for ambient air monitoring at petrol sheds is to evaluate worker and community exposure concerns regarding release of toxic chemicals to the air.

Other interventions introduced by the Health Ministry include : developing an air pollution control strategy: taking measures to determine the pollutants of concern for specific locations (based on health effects and the severity of the air quality problems in that area) identify measures to control sources of pollution and measuring air quality in various locations.

Q. You have also authored a book on air pollution. What is your message to our readers, especially, on the preventive aspect?

A. The solution lies with all of us- from the Government to the private sector to the community.