Causes, effects and the way forward
The kind of air pollution that is caused by mixture of smoke and fog is called smog. The term ‘smog’ was first used in early 1900s.
The term ‘smog’ was first coined by Dr Henry Antoine Des Voeux in his 1905 paper titled as ‘Fog and Smoke’. He used the term ‘smog’ to describe the polluted atmosphere over many British towns.
Two distinct kinds of smog
At least two distinct kinds of smog are recognized.
1. Sulphureous smog
It is also called the London smog. It is the product of presence of sulphur oxides in the air which is the result of burning of fossil fuels which contain sulphur. Dampness and concentration of suspended particles further aggravate this kind of smog.
In 1952, the clouds of smog which resulted from burning of coal covered the city of London, England. More than 4000 people died of respiratory ailments aggravated by smog. The smog was so severe that the roads, railways and airports were shut down.
2. Photochemical smog
It is produced when sunlight reacts with nitrogen oxides, which are emitted from vehicles, and at least one volatile organic compound (VOC) in the atmosphere. It is commonly produced when the vehicular emissions from burning gasoline and diesel come in contact with sunlight. It occurs mostly in the densely populated areas with a lot of vehicular traffic. This type of smog is often referred to as ‘Los Angeles smog’.
On July 26, 1943, sudden and severe smog was observed over Los Angeles, California. The residents believe that some country had launched a chemical attack on them.
Composition of Smog
Ø Nitrogen oxides
Ø Sulphur oxide
Ø Particulate matter
Ø Burning of coals in industrialized areas
Ø Smoke emitted from vehicles
Ø Forest and agricultural fires — Farmers put the crop residue on fire which becomes the prime cause of smog. In Delhi, smog is caused and aggravated by stubble-burning in its surrounding agricultural areas.
Ø Smoke from brick kilns
Ø Gradual loss of vegetation cover
Loci of smog are big cities where there is rush of traffic, and industries are located. The industrialized cities which are surrounded by mountains are more likely to face severe smog because the smog is trapped among the mountains. Los Angeles, California, and Mexico City have higher levels of smog because of this landscape.
1. It reduces visibility.
2. It is dangerous for human health. It can damage lung tissues and is extremely dangerous for the persons having respiratory problems. It may cause burning of eyes. It ultimately causes sickness and shortened lifespan.
3. It is unhealthy for animals and plants as well.
4. It creates a very bad view of sky whose colour changes from blue to brown or gray.
Air Quality Index (AQI)
Smog has a direct bearing on the Air Quality Index (AQI). AQI is developed to measure the quality of air/gauge the level of pollution in the air. It is a yardstick which runs from zero to 500. The rise in AQI implies greater level of air pollution and greater risk to public health.
The AQI is divided into six bands with each band showing different level of air quality and health concern.
Cause of Concern for Lahore
Average AQI for Lahore has crossed the figure of 300 in November this year which means that there exists a situation of health emergency as per the level of air pollution. Air quality in Lahore drops to the hazardous level in the winter season from November to February mainly because of the congestions of traffic on the roads, and the burning of remnants of crops in the surrounding areas of Lahore.
In November 2019, Lahore remained the 2nd most polluted city of the world with Delhi being on the top. However, for some days, it also surpassed the Capital of India.
Real time Air Quality and Pollution city ranking published by IQAir
IQAir publishes the air quality data of major cities on real time basis. For example, the ranking of the world cities on November 27, 2021, at 11:00am, on the AQI is as under:
As per its report titled as ‘World’s most polluted cities 2020’ which is based on the data of the complete year, Lahore remained the 18th most polluted city of the world, Faisalabad was on 29th position.
The Way Forward
a. In order to curb this environmental issue, many countries have adopted measures to control burning of the waste material and smoke emissions. Restrictions are imposed on factories to regulate the burning of coals or fuels so that smoke emissions can be kept under check.
b. Smog is not only an environmental problem but is also a kind of hazard that requires a responsible civic response from the community at large. The people would have to adopt healthy lifestyle. They should walk more and drive less. Car pooling is a good idea that would reduce the traffic on the roads. In a country like ours, it is a pressing need of the hour to improve public transport system. The culture of running bicycles should be promoted by our opinion leaders and celebrities.
c. Smoke-emitting vehicles should not be allowed to come on the roads. Each vehicle should get engine fitness certificate and then be allowed to be driven on the roads.
d. An awareness campaign should be launched to educate the farmers regarding the harmful effects of smog, and they should be advised not to burn the crop residue. Penal action should be taken against those who burn the crop residue and cause smog.
e. It is the need of the hour that the real-time air quality data should be published and awareness be created regarding the health emergency which exists so that the general public may take measures to control the air pollution. Wearing masks is not only the basic preventive measure for the Covid-19 but it also remains the best prevention strategy to avoid the harmful effects of smog and air pollution. Certain electronic gadgets like air purifiers may be used to clean the air of the closed spaces like the rooms and vehicles. People may avoid doing exercise outdoor during the season of smog.
f. The government should press the owners of brick kilns to use zigzag technology which releases fewer emissions than the traditional apparatus used in brick kilns.
Smog has become a great environmental hazard which has many harmful effects on public health. It has created an emergency-like situation in many countries including Pakistan. The government and the community should join hands and take steps to tackle this emergency before it is too late.
The writer is a civil servant, belonging to the Police Service of Pakistan (PSP).