What is Smog, What Causes It, and How to Protect Yourself?

Indian capital New Delhi is grappling with severely hazardous air quality as pollution levels are hitting the rooftop. On Monday morning, a toxic haze engulfed the city, affecting visibility and delaying

flights and trains. The city's air quality index, or AQI - which measures PM2.5, fine particulate matter that clogs lungs, and other pollutants - was more than 30 times the limit recommended by the World Health Organization. Exposure to this level of pollution can lead to serious health issues - especially in children and elderly people. According to experts, more than 99 per cent of the population is now breathing air that is polluted enough to harm health. This widespread exposure to unsafe air has made air pollution one of the most urgent global health challenges in recent times. However, smog itself is not a single pollutant but a combination of substances like ozone, fine particles, and nitrogen gases. And because of these different substances, they affect different groups of people differently. Smog is not just a public health concern that causes discomfort like coughing or eye irritation, but also worsens existing heart and lung conditions and increases long-term health risks.

What is smog?

Smog is a severe form of air pollution, a hazy layer in the atmosphere that reduces visibility, formed from the word “smoke” and “fog,” and consists of pollutants like nitrogen oxides, sulfur dioxide, ozone, and particulate matter from vehicles, industries, and burning fossil fuels. When these pollutants react with sunlight, they form a thick layer of ground-level ozone. The term was coined by Dr Henry Antoine des Voeux in a paper he titled Fog and Smoke, published in July 1905. It described the combination of smoke and fog that plagued London during the early 1900s.

How does smog get formed?

Smog is formed through the following processes:

Emissions

Pollutants like nitrogen oxides and volatile organic compounds are released into the atmosphere from various sources like industries, vehicles, and power plants.

Sunlight

When sunlight interacts with these pollutants, chemical reactions occur.

Photochemical reactions

The sunlight breaks down the pollutants, forming secondary pollutants like ground-level ozone and other harmful compounds.

Temperature inversions

In certain weather conditions, a temperature inversion occurs, trapping the pollutants close to the ground instead of allowing them to disperse.

Fog and moisture

When smog combines with fog or high humidity, it creates a visible haze and reduces visibility, making the air appear hazy or foggy.

Accumulation

Over time, the pollutants accumulate, forming a dense and visible smog layer.

What are the adverse effects of smoking on your health?

Doctors warn that smog can be extremely hazardous because it can cause an adverse impact on your health. It seriously affects health both in the short and long term. The most common adverse smog effects on human health include:

Respiratory issues

Coughing, breathing discomfort, worsening of asthma, bronchiolitis, and chronic obstructive pulmonary disease.

Eye and throat irritation

Red, watery eyes and irritation of the throat lining.

Cardiovascular effects

Increased risk of cardiovascular disease, including events such as stroke, and worsening of existing heart conditions

Neurological effects

Links to neurological disorders, such as Parkinson’s disease, with prolonged exposure

Pregnancy

Impaired foetal health, including low birth weight or reduced birth length

Cancer risk

Long-term genetic changes that may raise the risk of various cancers, particularly lung cancer

How can you protect yourself?

• Always stay informed
• Avoid strenuous exercises or workouts during peak hours, usually from late morning to early evening. And so, opt for early morning routines
• Use high-efficiency particle air (HEPA) or HEPA air cleaners
• High-quality particle-filtering respirators like N95 masks reduce particulate exposure significantly