Dr. R.M.S.I. Rajapakse

Dr. R.M.S.I. Rajapakse |Clyto Access

Lecturer (Probationary), Rajarata University of Sri Lanka, SRI LANKA


Expertise: Nano technology


Dr. R.M.S.I. Rajapakse holds a Second Class Honours (Upper Division) MBBS Degree from Rajarata University of Sri Lanka (2016) with distinctions in Physiology, Community Medicine and Forensic Medicine. He is currently serving as a Lecturer (Probationary) at the Faculty of Medicine and Allied Sciences of the same University. He has a few communications at International Conferences to his credit. He is an emerging young medical scientist interested in research activities in Respiratory Diseases.




World Health Organization (WHO) estimates, based on epidemiological data, air pollution is linked to seven million premature deathsannually1. Air pollution is caused by various gases such as ozone, oxides of carbon, oxides of sulphur (SOxs), oxides of nitrogen (NOxs) combined with airborne particulate matter such as ice crystals, dust particles, carbon particles and soot. Particle size is an important factor determining their health effects2,3. Atmospheric particulate matter is present in a vast size range from a few nm to hundreds of µm. Although particles can have various shapes,in atmospheric particles, size is defined by considering them to be spherical and the diameter of the idealized sphere is considered as the particle size. Depending on particle size, atmospheric particles can be divided into different categories: those with size above 2500 nm (2.5 µm) are called coarse particles and those below are fine particles. WHO, USEPA and EU use the parameter PMxto describe particle size which refers to a particulate matter comprising ofparticles less than x µm in diameter. Super-coarse particles are extremely high in size range and they usually settle down due to gravitational effect soon after their generation. Fine particles accumulate in the atmosphere for a prolonged time and they are subdivided into fine (PM0.1 to PM2.5) and ultrafine (below PM0.1) particles. Ultrafine particles,now referred to as nanoparticles, by definition are particles with at least one dimension in the range of 1 nm to 100 nm. Airborne nanoparticles are formed from gaseous precursors emitted from various natural and anthropogenic sources such as exhausts of industries, motor vehicles, and volcano eruption, acting as gas phase precursors for the formation of smaller molecular clusters which grow rapidly to ~1 nm size particles which agglomerate or grow up to about 50 nm particles. Nanoparticles are also emitted directly to the atmosphere from motor vehicular emissions and from industrial sources and from those generated by the friction of road surfaces on motor vehicle tyres. In recent years, atmospheric nanoparticulate concentration has increased dramatically due to increased use of nanomaterials in industries, in consumer goods and in electronic and opto-electronic devices. Chemical compositions of atmospheric nanoparticles are highly variable comprising of inorganic components such as sulphates, nitrates, ammonium chloride, trace and heavy metals, elemental and organic carbon, crystalline materials, biological material such as viruses, volatile and semi-volatile organic compounds such as dioxins, hydrocarbons, polycyclic aromatic hydrocarbons (PAHs). Coarser particles are too large to be inhaled and usually accumulated at the top of the airway which are naturally removed by coughing or mucocillliary escalator mechanism. However, nanoparticles are breathed deeply into the lungs and are able to penetrate alveolar epithelium, therefore nanoparticles are responsible for lung diseases3,4 including lung cancer due to their huge surface area per volume and consequent high reactivity compared to fine and micro-particles and cardiovascular diseases extending even to autonomic dysfunction5. According to Chawes, et al.,fine particulate air pollution (PM2.5), is the cause of 1% of deaths from acute respiratory illnesses in children,3% of mortality from cardiopulmonary disease, and about 5% of mortality from cancers originating in the respiratory tract. This amounts to a staggering 6.4 million years of life lost6.In Sri Lanka, the prevalence of childhood asthma is higher in Kandy than Colomboalthough the vehicle density and consequent vehicular emissions in Colombo7, the capital of Sri Lanka, is much higher than that of Kandy. Geographically, Kandy is situated in a valley surrounded by mountains and Colombo is in the coastal area of flatlands. Kandy air is relatively static and pollutants are accumulated while pollutants are flushed off by sea breeze in Colombo. As such, not only the amount of pollutant added to air but also their fate is very important in assessing their health effects caused by these air pollutants. Further studies are needed for evaluation ofin vivo health effects of inhaled nanoparticles.

Related Conferences :

2nd world summit on Nanotechnology and Nanomedicine Research