In recent days, photochemical smog is a serious problem, especially in urban areas. The terminology refers to a mixture of hazardous gaseous emissions and fog. It is usually seen as yellowish or blackish fog, which suspends in the atmosphere or forms a ceiling in the air due to inversion. It happens when fume, emissions, and particulates (nitrogen and sulfur oxides and volatile organic compounds) react in the presence of sunlight to form ground-level ozone. The emissions of harmful gases from vehicles and industries, as well as the combustion of wood and coal – together with the buildup of certain weather conditions, are the main causal agents of smog.
The gaseous emissions such as carbon monoxide from vehicles are the main elements that form smog, when acted upon by the sun’s ultraviolet light, together with particulate matter and volatile organic compounds. Dense urban areas suffer more from the smog because of huge traffic, industries, and combustion of different types of fuel. Smog has serious damaging effects on people, plants, and animals. Below are a few causes, effects, and solutions to mitigate photochemical smog.
Smog is a type of air pollutant. The word “smog” was coined in the early 20th century as a portmanteau of the words smoke and fog, to refer to smoky fog, its opacity, and odor. This kind of visible air pollution is composed of nitrogen oxides, sulfur oxides, ozone, smoke, or particulates among others (less visible pollutants include carbon monoxide, CFCs, and radioactive sources). Human-made smog is derived from coal emissions, vehicular emissions, industrial emissions, forest and agricultural fires, and photochemical reactions of these emissions.
Smog-forming pollutants from numerous point and non-point sources such as factories, consumer products, or vehicles are the typical causative factors of photochemical smog. In most urban areas, more than 50% of smog is formed in consequence of vehicular emissions. Mostly, the occurrences of smog are associated with the relationship between weather patterns and heavy motor vehicle traffic, industrial and other consumer product emissions. Consumer products include solvents, paints, plastic packaging, and sprays.
Smog is of two types: photochemical smog – commonly formed in urban areas and originates from elevated levels of hydrocarbon burning and nitrogen oxides in the presence of sunlight, and sulfur smog – formed when there is an increased level of sulfur oxides in the atmosphere.
Smog-forming pollutants from numerous sources such as factories, consumer products, or vehicles are the typical causative factors of photochemical smog. In most urban areas, more than 50% of smog is formed in consequence of vehicular emissions. Mostly, the occurrences of smog are associated with the relationship between weather patterns and heavy motor vehicle traffic, industrial and other consumer product emissions. Consumer products include solvents, paints, plastic packaging, and sprays.
The use of coal as fuel in heating, or in power production plants, discharges high concentrations of sulfur oxides in the atmosphere. The effects are worsened by high levels of suspended particulate matter and dampness in the air. For instance, coal induced smog has been widely experienced in London up to the middle ages of the 20th century, which is termed as “London Smog”. In China, Harbin, coal-induced smog contributed to the closure of roads, schools, and airports in the autumn of 2013.
Emission of harmful gases like carbon monoxide (CO), from fuel combustion in automobiles are the chief contributors of smog formation. Industries equally emit scores of gaseous emissions and fumes which leads to smog formation.
The primary precursors are oxides of nitrogen, volatile organic compounds, carbon monoxide, fumes, and sulfur oxides. These compounds react with moisture, heat, sunlight, and ammonia among other compounds, to form the toxic vapors, suspended particulates, and ground-level ozone, that makeup smog.
Photochemical smog can also be a consequence of natural causes, for instance: volcanic eruptions. Volcanic eruption discharges high concentrations of sulfur dioxide and particulate matter in the air – the two primary constituents for smog formation. Radiocarbon amounts of some specific plant lives are believed to cause smog in a few locations. For instance, the Los Angeles creosote bush is linked to smog occurrences in the area.
Smog is harmful to humans, animals, plants, and nature as a whole. Many people’s deaths were recorded, notably, those relating to bronchial infections. Heavy smog also blocks the sunlight from reaching the earth. This unavailability of sunlight cause vitamin D deficiency, leading to issues like rickets. When a city or town gets covered in smog, the effects are felt immediately. Smog can be responsible for any ailment, from minor pains to deadly pulmonary diseases such as lung cancer. Smog is well known for irritating the eye. It may also result in inflammation in the tissues of the lungs, giving rise to pain in the chest. Other issues or illnesses such as colds and pneumonia can also be caused by smog. The human body faces great difficulty in defending itself against the harmful effects of smog.
Minor exposure to smog can lead to greater threats of asthma attacks; people suffering from asthma problems must avoid exposure. Smog also causes premature deaths and affects densely populated areas, where it build up to dangerous levels. The highly affected include the elderly, kids, and those with cardiac and respiratory complications.
The ground-level ozone present in the smog also inhibits plant growth and causes immense damage to plants. Crops, vegetables like soybeans, wheat, tomatoes, peanuts, and cotton, are subject to infection when they are exposed to smog. The smog results in mortifying impacts on the environment by killing innumerable animal species and green life, and it takes time to adapt to breathing and surviving in such toxic environments.
Smog is an emerging problem, especially due to the fast modernization or industrialization, as the hazardous chemicals involved in smog formation are highly reactive to the elements present in the atmosphere. Smoke and sulfur dioxide pollution in urban areas is now at considerably lower levels than in the past, as a result of the law passed to control emissions, and due to cleaner emission technology.
.Vehicle Exhaust Fumes
2.Fossil Fuel-Based Power Plants
3.Exhaust from Industrial Plants and Factories
4.Construction and Agricultural Activities
POSSIBLE SOLUTIONS TO CONTROL SMOG
Drive less. Walk, ride a bike, and use public transportation whenever possible.
Take care of cars. Getting regular tune-ups, changing the oil on schedule, and inflating tires to the proper level, can improve gas mileage and reduce emissions.
Fueling up vehicles during the cooler hours of the day— at night or early in the morning. This prevents gas fumes from heating up and producing ozone.
Avoid products that release high levels of Volatile Organic Compounds (VOCs). For example, use low-VOC paints.
Avoid gas-powered yard equipment, like lawnmowers. Use electric appliances instead.
Better to develop some ecofriendly, green, cheap, and renewable energy sources exploiting sunlight and water through photochemical, photo-electrochemical, and electrochemical water splitting.
STRATEGIES ADOPTED BY OTHER COUNTRIES TO CONTROL SMOG
Paris bans cars in many historic central districts on weekends, imposes odd-even bans on vehicles, makes public transport free during major pollution events, and encourages car-and bike-sharing programs. A long section of the right bank of the river Seine is now car-free, and a monthly ban on cars has come into force along the Champs-Elysées.
Reports that pollution levels in Delhi matched those in Beijing spurred the city to ban all new large diesel cars and SUVs with engines of more than 2,000CC and to phase out tens of thousands of diesel taxis. The city has experimented with alternately banning cars with odd and even number plates and is now encouraging Uber-style mini buses on demand. Other cities considering diesel bans are Dublin and Brussels.
Politicians want to ban the sale of all petrol and diesel cars from 2025, allowing only electric or hydrogen vehicles. The proposed law would allow anyone who already owns a petrol or diesel car to continue using it. Most cities encourage bicycle use.
Freiburg in Germany has 500km of bike routes, tramways, and a cheap and efficient public transport system. One suburb, Vauban, forbids people to park near their homes and makes car-owners pay €18,000 for a space on the edge of town. In return for living without a car, people are offered cheaper housing, free public transport, and plentiful bicycle spaces.
Conclusively, SOx, COx, and NOx released from the burning of fuels in automobiles and power generation houses are major causes of air pollution. The scientific community is paying heed to the development of eco-friendly energy sources which can fulfill the energy needs and to combat air pollution to make a world a better place to live and thrive!