Small But Deadly: The Spectre Called SPM

10/06/2015 12:26 PM IST | Updated 15/07/2016 8:25 AM IST

From the beginning of the industrial age, the quality of the atmosphere around us has been subject to a steady decline. One of the chief contributors to this change is the burning of fossil fuels to sustain modern industry and urban transport. The effect of air pollution is visible both in humans, flora and fauna, and in our immediate surroundings. On top of this, air pollution is not only determined by exterior conditions but also by the ambient air quality inside our homes and places of work. The pollutants present can be in many forms, and one of the most dangerous is suspended particulate matter (SPM).

SPM has its genesis in dust, fumes, mist, smoke and in its deadlier cousin: smog. A major chemical component of SPM is lead. Other particularly harmful constituents include nickel, arsenic and sulphur. SPM has a major impact on lung and lung tissue, nose tissue and tear ducts; scientists believe that prolonged exposure to polluted air is more harmful than passive smoking. SPM is a driver of major air pollution rooted in both urban and rural environments, but no effective means of curbing it have yet been discovered.


SPM has been linked to major environmental disasters including the London Fog of 1952. Today, it is not only an urban phenomenon, but is present in rural areas which use wood charcoal or unwashed coal for cooking and heating needs. People in these areas are particularly prone to bronchial diseases due to continuous inhalation of wood smoke and lack of effective outlets for such SPM-rich smoke from the household environment. Other sources of SPM in semi-urban and rural areas are from slash-and-burn cultivation which is known to release enormous amounts of carbon dioxide in the air, industrial incinerators which release unfiltered paper smoke, and limestone quarries, which contribute harmful oxides of nitrogen and other organic compounds.

The basic danger when dealing with SPM is that the level of threat is proportional to the increase in the minuteness of the particles. Absorbed by lung tissue, SPM creates a fine layer on the surface of the lung, effectively clogging air circulation which gives rise to pulmonary diseases like asthma.

" Absorbed by lung tissue, SPM creates a fine layer on the surface of the lung, effectively clogging air circulation which gives rise to pulmonary diseases like asthma."

Particulate matter also has a harmful effect on the climate as any increase in the suspension levels leads to greater amounts of sunlight getting trapped within the upper atmosphere. This leads to increase of heat in the upper atmosphere leading to increase in the levels of global warming.

The effects of high concentration of SPM can also be seen in plants. Trace elements like arsenic, cadmium, cobalt, chromium, selenium etc, which are human and animal carcinogens, play havoc with the florian ecosystem. Studies by the Environmental Health Perspective in 2007 have revealed that the total daily mortality rate in humans increased by approximately 1% for every 10 miug/metre cube increase in SPM concentration and lung cancer rates increasing to 36% per 10ug/m3 of PM2.5 .

Further, the greater the density of population the greater the chances of SPM pollution. This becomes particularly clear when there is an analysis of air quality in core urban areas. The situation may be exacerbated by other factors too. In a study done in Jaipur last year, the Rajasthan State Pollution Control Board estimated that the air quality over the city deteriorated by three times from the normal on the day after the festival. This lead to an increase in minor health ailments like eye irritation clogged nasal and bronchial tracts, sustained coughing fits and other mucous problems all around the city.

The World Health Organization (WHO) estimates that fine particulate air pollution (PM-2.5) causes about 3% of mortality from cardiopulmonary disease, about 5% of mortality from cancer of the trachea, bronchus, and lung, and about 1% of mortality from acute respiratory infections in children under five years of age globally.

Researchers suggest that even short-term exposure at elevated concentrations contributes significantly to heart disease. A study in The Lancet concluded that traffic exhaust is the single most serious preventable cause of heart attack in the general public, the cause of 7.4% of all attacks. It has been suggested that particulate matter can cause brain damage and increase the risk of developing Alzheimer's disease .

One particular area of change that can be addressed are legislative limits for engines, which are presently in terms of emitted mass, and which may not enough to prevent health hazards.

Interestingly, there exist proposals for new regulations in some countries which suggest alternate means to limit particle surface area or emission of particulate matter, but governments are slow to act. Perhaps a thrust to change this situation would help ease some of threat facing us presently.

It is time we seriously recognise the effects of SPM pollution and address this silent spectre before it causes any further damage.

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