Air pollution: a silent killer

Last week, the authorities, especially those at the National Building Research Organisation (NBRO) warned of health hazards due to the air pollution mainly in Colombo and suburbs. At the same time, the US Embassy’s Air Quality Monitor in Colombo indicated unhealthy values of air quality with 167 Air Quality Index (AQI) recorded by 10.00 pm last Tuesday. By Wednesday morning, the AQI readings continued to rise to 173 by 8.30 am before declining to a 165 by 10 am. Despite the fluctuations, readings continued to indicate an unhealthy level of air quality throughout the week.  

According to NBRO authorities and other relevant institutions, the standard level of air quality is measured at around 50 and the index level between 151 and 200 indicates possible health effects for everyone.  

Though the authorities attributed the surge in air pollution in Colombo mainly to the winds coming from the highly polluted Indian Capital, Delhi where the pollution level stood at more than 500 last week, this was not the first time when the air quality declined to an unhealthy level in Colombo. The authorities at the NBRO, US embassy and the CEA occasionally inform the general public of this situation. However, the statistics indicated in these warnings do not make any sense to the ordinary people; they are just numbers to them.   

According to reports prepared by relevant authorities, many different air pollutants can impact health — nitrogen oxide, carbon monoxide, and ozone, among them. But air pollution is classified by environmentalists in two ways: by the number of micrograms of PM 2.5 (particles smaller than 2.5 microns and less in diameter) and by PM 10 (particles that are 10 microns and less in diameter) in one cubic metre of air. (PM stand for particulate matter).  

Particles larger than 10 microns in diameter (a micron is one millionth of a metre) are filtered through the nose and the upper respiratory tract while those smaller than 10 microns go right inside the lung. This fraction is called PM10 fraction and smaller particles with diameters less than 2.5 microns called the PM 2.5 fraction are even more hazardous.   

The widths of the larger particles in the PM2.5 size range would be about thirty times smaller than that of a human hair, they say. Exposure to these fine particles can cause health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath.   

In 2005, WHO has calculated that more than 20% of the admissions to the Lady Ridgeway hospital in Colombo due to asthma can be correlated to the PM10 values in air. An earlier study in 2004 correlated increased admissions of children with asthma requiring nebulisation to the same hospital on days when the sulphur dioxide levels were high.   

With the emission by the vehicles having mainly been attributed to the air pollution in Sri Lanka and with many hundreds of thousands of vehicles having been added to the vehicular population after 2005, one has to imagine the level of health hazard caused especially to the innocent children by the air pollution now.  

According to statistics compiled by Prof. Amal Kumarage of the Moratuwa University last year, on an average, 300,000 vehicles, made up of 15,000 buses, 10,000 trucks and 225,000 private vehicles, enter the Colombo city daily. There are 7.24 million vehicles in Sri Lanka out of which 4.04 million are motorcycles with 1.14 million three wheelers and 600,000 vehicles are registered every year.   

The number of vehicles registered has increased by nearly 14 folds between 1990-2010 while the number of three wheelers and motorcycles increased by a whopping 600% during the last 20 years.   

The lack of proper high quality public transport system has resulted in over 50% of the working population to use private vehicles to commute to work, according to Prof. Kumarage. Average speed for vehicles in Colombo was 22 km/hour in 2012 while it was 17 km/hour last year. Vehicles travelling in traffic jams produce more fine particles in the form of soot which adversely affects our health, he points out.   

Though one of the main objectives of the proposed agreement with the Millennium Challenge Corporation (MCC) is said to be resolving of congestion on the roads in the Western Province, its political implications are not clear. Yet, Sri Lanka badly needs a master plan to resolve the issue.