Qualité de l’air à Salem

What is the air quality index of Salem?

Salem is a large city in Salem district, located on the banks of Thirumanimutharu River in the Indian state of Tamil Nadu. It is 186 kilometres southeast of Bangalore and about 340 kilometres southwest of the state capital, Chennai. In 2011 it had an estimated population of 829,267 people.

In early 2021, Salem was experiencing a period of air that was classed as being “Unhealthy for sensitive groups”. This classification is in accordance with recommendations from the World Health Organisation (WHO). The US AQI reading was 112! The recorded level of PM2.5 was 40.2 µg/m³.

With figures as high as these, it is advisable to close doors and windows to prevent the ingress of dirty air into the room. Those people of a sensitive disposition should avoid venturing outside until the air quality improves. Outdoor exercise, in general, should be avoided by all and the use of an air purifier would be advantageous if one is available.

India has 14 of the world's 15 most affected by air pollution.

Does the level of air quality differ in Salem throughout the year?

Due to the continuous pollution caused by smoke emitted from vehicles and the burning of straw, the atmosphere is getting very bad.

Burning of stubble and other organic residue is a traditional way of preparing the ground for the next season’s crops.

The Indian government is trying to curb this practice because of the huge amount of air pollution it produces.

The Government distributed 24,000 tractor-mounted ‘happy seeders’ to cut down the rice stubble and sow wheat seeds simultaneously. Once these machines have been tried, the farmers are beginning to find out that they are not as good as the government thinks they are. Farmers have also complained about problems while sowing and low germination of wheat seeds when sown with ‘happy seeders’. Many machines have been dumped only after two years of use.

The number of deaths due to air pollution is increasing rapidly in India, it is very worrying. Since 1990, untimely deaths due to PM2.5 (microscopic particulate matter) pollution in China have increased by 17.22 per cent, while in India this figure has gone up by 48 per cent. The surprising thing is that the number of deaths in China due to ozone pollution has been almost constant since 1990, but India has registered a growth of 148 per cent. This shows that air pollution is not only related to dust particles but also toxic gases that are polluting the air in a dangerous way.

What is the main source of air pollution in Salem?

In the year 2005, there were a loss of 6 million tonnes of wheat, rice, soybean and cotton crops in India. It was discovered that the damage done to crops was due to ozone (O₃) at the ground level. This ozone accumulates on the ground when pollution from vehicles, power plants, refineries and other sources combine with sunlight to become a harmful gas. This is how smog is formed during winter in Salem. Ozone is the main cause of smog. Ozone levels are rising on the ground due to lack of clear rules regarding air quality, which is becoming a problem for many states of India.

As a busy industrial city, the emissions from road vehicles are major sources of air pollution. As with many cities in India, the vehicles are a lot older than in other countries and therefore lack the modern technology that filters the exhaust fumes. Many vehicles on India’s roads are well over 15 years old. The large amount of heavy-duty trucks is also a major source of pollution.

Another source of air pollution in and around Salem is the use of dried animal dung as fuel.

Animal dung is often mixed with leaves and straw and twigs and formed into “cakes” and dried. These are then used as fuel for both cooking and heating the home in cooler weather. They are often burnt in kitchens where there is very little ventilation so the polluted air has nowhere to escape to. Also, the young children of the household will be with mum as she prepares and cooks the dinner.

The advantages outweigh the disadvantages in that they are very convenient, very cheap and remarkably efficient. They can also be used as currency in exchange for goods in some remote villages.

What can be done to improve the air quality in Salem?

During the religious festival of Diwali, it is traditional to let off firecrackers but surprisingly, these are a major source of air pollution. They pollute the air so badly that the figures from the air monitoring stations can see the increase.

In cities where the level of air pollution is very high, firecrackers are banned entirely. With the lesser polluted cities, they are limited to just two hours of burn time for them. There are newer firecrackers that are “green” but they still produce a large amount of smoke and soot.

What are the effects of breathing Salem’s poor quality air?

When ozone dissolved in the air enters the lungs of humans, it tries to close the small holes of the lungs i.e. the alveoli. In this case, cough and chest pain may be complained of. In severe cases, the lungs may also stop functioning.

Dry air consists of about 78 per cent nitrogen, 21 per cent oxygen and 1 per cent argon. There is also water vapour in the air, which makes up between 0.1 per cent and 4 per cent of the troposphere. Warmer air usually contains more water vapour than cooler air.

Particulate matter (PM) is the air pollutant that has the greatest impact on people's health in Europe. Think of fine dust as particles that are so light that they can be carried in the air. Some of these particles are so small that they not only penetrate deep into our lungs but like oxygen, they also get into our bloodstream.

According to the WHO report on data on the health effects of air pollution, long-term exposure to fine dust can trigger atherosclerosis, undesirable birth outcomes and respiratory diseases in children. The study also suggests a possible link between nervous system development, cognitive skills and diabetes, and reinforces the causal link between PM2.5 and deaths from cardiovascular and respiratory diseases.