The phrase "urban air pollution" describes the smog that surrounds and exists in urban areas. In locations with a high density of people, urban air pollution is worse. Both human health and the local climate are impacted by air pollution. Natural sources of urban air pollution include volcanic eruptions, thunder, surface dust, and naturally occurring particulate matter. Nevertheless, manmade activities are a primary cause of urban air pollution.
Urban Air Pollution: What Is It?
• Urban air pollution is the term used to describe air pollution in and around cities. Urban air pollution is more prevalent where there are denser inhabitants.
• Both human health and a region's climate are impacted by air pollution.
• The World Health Organization (WHO) estimates that exposure to ambient (outside) air pollution results in 4.2 million fatalities annually.
• Urban air pollution is mostly caused by anthropogenic activities such transportation, residential fossil fuel usage, industrialization, electricity generation, combustion, agriculture, and beauty goods.
• While some of the causes of urban air pollution are natural, most of them are artificial and strongly dependent on human activity.
Urban Air Pollution Sources
• The usage of private vehicles, particularly older, diesel versions, is the main contributor to urban air pollution.
• Roughly one-fourth of the airborne particulate matter is caused by vehicles.
Domestic use of fossil fuels
• Solid fuels are still used for heating and cooking by half of the world's population.
• These fuels, which include wood, charcoal, and coal, are burned in inefficient stoves that release a lot of pollutants into the air that are bad for your health and contribute to global warming.
• Additionally, 1.2 billion people are thought to use paraffin lamps at home, which adds to air pollution and raises the risk of cardiovascular and respiratory ailments.
• The need for energy increases in tandem with population growth. Fossil fuels are widely employed to generate energy in order to meet that demand because they are affordable and easily accessible.
• Power stations that burn coal are a substantial source of air pollution in cities.
Combustion and Agriculture
• Urban air pollution is a result of the activity of material combustion, which releases harmful gases into the environment.
• CO2 and CO are released during complete and incomplete combustion, respectively. These two gases add to the smog in cities.
• Other gases, like NO2 and methane (CH4), are also released into the atmosphere as a result of agriculture.
• The haze that covers Delhi in the winter is attributed to the burning of twigs in Punjab, Rajasthan, and Haryana.
• It emits a lot of harmful pollutants into the environment, including cancer-causing polycyclic aromatic hydrocarbons and dangerous gases including methane (CH4), carbon monoxide (CO), and volatile organic compounds (VOC).
• A recent study found that using cosmetic products increases urban air pollution.
• The majority of cosmetics and colognes include volatile organic compounds (VOCs), which when used emit into the air and contribute to urban air pollution.
• The usage of these cosmetics increases along with the population, which adds to pollution.
• Firecrackers were nevertheless used extensively during Diwali despite the ban. Although it might not be the main reason for air pollution, it undoubtedly helps it to build up.
Gulf States-related dust storm
• A dust storm from the Gulf nations during the 2017 haze aggravated an already bad condition.
- Ground-level ozone, a pollutant that is harmful to human health, is formed as a result of a chemical reaction between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
- In other words, pollutants emitted by automobiles, power plants, and material combustion interact with sunlight to produce ozone.
- Ozone causes smog and makes breathing difficult.
Particulate matter (PM10, PM2.5)
- PM10 particles have an aerodynamic diameter of less than 10 m, while PM2.5 particles have an aerodynamic diameter of less than 2.5 m.
- PM particles inhaled penetrate deep into the lungs and enter the bloodstream.
- The concentration of PM10 and PM2.5 is the most commonly used metric to indicate the quality of air in urban areas.
- North America, Western Europe, Turkey, and the Republic of Korea are the countries most concerned about PM formation as a result of anthropogenic activities.
- PM is linked to serious health consequences such as respiratory diseases, cardiovascular dysfunction, and lung cancer.
Sulphur oxides (SOₓ)
- Colourless gases found in the lower atmosphere are sulphur oxides.
- These gases can be detected by smell and taste depending on their concentration.
- The primary source of these pollutants is the combustion of sulphur-containing fossil fuels.
- Thermal power plants, in particular, that burn sulphur-rich coal, are known to be the primary sources of anthropogenic sulphur dioxide emissions worldwide.
- Domestic coal combustion and vehicle emissions can also contribute to high local ambient sulphur dioxide concentrations.
- Sulphur oxides can also produce sulfuric acid when they react with rainwater (acid rain).
Nitrogen oxides (NOₓ)
- Nitrogen is found as a compound in fossil fuels, and nitrogen oxides are produced during fuel combustion processes.
- Nitrogen oxides have a negative impact on the respiratory system and cause airway inflammation at high levels.
- Long-term exposure, on the other hand, can reduce lung function and increase allergic reactions.
- The majority of these compounds are emitted by power plants, vehicles, and industrial and domestic combustion processes. The main cause in cities is road transport.
- Furthermore, NOx contributes to the formation of particulate matter and ground-level ozone.
Carbon monoxide (CO)
- Carbon monoxide is a highly toxic air pollutant that is colourless, odourless, and tasteless.
- The incomplete combustion of fossil fuels such as gasoline, natural gas, oil, coal, and wood produces CO.
- Vehicle emissions are the most significant anthropogenic source of CO.
Volatile Organic Compounds (VOCs)
- VOCs are compounds with a low boiling point and the ability to evaporate at room temperature.
- These substances are hazardous to human health.
- Paints, varnishes, waxes, oil-dissolving solvents, cleansers, fuels, disinfectants, cosmetics, and glues are all sources of VOCs.
- They can also be produced by smoking and fuel combustion.
- VOCs also play a role in the formation of ozone.
Urban Air Pollution: Issues
• The terrestrial environment is significantly impacted by ground air pollution.
• Effects on the marine ecosystem include eutrophication, mercury buildup in aquatic food, and acidification of lakes.
• Another frequent occurrence in forest ecosystems brought on by long-term pollution accumulation is soil acidification.
• The ecosystems of plants and animals that rely on soil for nutrition are indirectly impacted by soil pollution.
• Wet and dry nitrogen deposition on vegetation and soil surfaces can be brought on by agricultural and vehicular operations.
• The biological diversity may be impacted by the harmful impacts of air pollutant emissions.
• Because of air pollution, SO2 and NOX emissions in the atmosphere undergo oxidation and moist deposition, which results in acid rain. In turn, this means that acid rain may harm our biodiversity.
• Ozone is yet another pollutant that is harmful to both plants and animals. It slows down photosynthesis and slows down plant growth.
• Both human and animal lung tissues can be harmed by ozone, which can lead to respiratory disorders.
• Additionally, elevated oxidative stress has an impact on animal reproduction, which has an impact on any species' population.
• Particularly for rare species, this might be hazardous.
• Residents who reside in places with high pollution levels and poor air quality are at risk for developing major health issues.
• Emissions of PM, O3, SOX, and NOX have the potential to be harmful to human respiratory and cardiovascular systems.
• Approximately 1.1 million people died as a result of air pollution in 2015, according to an analysis of PM2.5 concentrations in India.
On Buildings and Materials
• Emissions of SOX and NOX can damage plant and animal life, as well as material surfaces and potentially cause structural damages.
• Discoloration, material loss, structural failure, and soiling are some of the detrimental effects.
• This can shorten the useful life of buildings and seriously harm historical structures and monuments.
• One such illustration is India's white-marble Taj Mahal, which is turning yellow as a result of acid rain and SOX emissions from industry.
• The Charminar in Hyderabad, another historical landmark in India, is deteriorating owing to pollution and is turning black.
• Such heritage zones' decline is a significant source of worry.
Reports On Air Pollution's Effects
State of the Global Air Report for 2020
• India has the highest global per capita pollution exposure, according to the State of Global Air 2020 Report.
• Due to severe air pollution in India in 2019, more than 116,000 infants passed away within a month of birth.
• According to the findings, prenatal exposure to air pollution is associated with low birth weight and early birth.
• In 2019, more than 1.67 million deaths in India each year from stroke, heart attack, diabetes, lung cancer, chronic lung diseases, and newborn illnesses were also attributed to prolonged exposure to outdoor and indoor air pollution.
Report by the World Health Organization
• One in every nine deaths, or the biggest environmental cause of premature mortality, is now attributed to hazardous air, according to the WHO.
• It claims 7 million lives annually, killing more people than HIV, TB, and malaria put together.
• An estimated 4.2 million premature deaths globally are attributed to ambient air pollution, mostly due to heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections in children.
Governmental Measures to Combat Air Pollution
• Notification of industry-specific emission and effluent limits as well as national ambient air quality standards.
• Establishing a monitoring system to evaluate the air quality outside.
• Cleaner gaseous fuels are being introduced, including CNG, LPG, and ethanol blends.
• Launching soon is the National Air Quality Index (AQI).
• By April 1st, 2020, vehicle standards will be changed from BS-IV to BS-VI.
• Biomass burning is not permitted.
• Promotion of the public transit system.
• Environmental Protection Certificate.
• Air (Prevention and Control of Pollution) Act of 1981 directives.
• Installation of devices for continuous (24/7) online monitoring by 17 industries that produce pollution.
• Limiting the explosion of noxious crackers.
• Notifying Delhi of a graded response action plan, determining source-specific responses for various air pollution levels, etc.
• Four-Pillar Strategy of WHO: In order to combat the detrimental impacts of air pollution on health, WHO issued a resolution in 2015. This four-pillar strategy urges a more forceful international response to the harmful impacts of air pollution on human health. The following are these four pillars:
o Expanding one's knowledge.
o Monitoring and reporting.
o Global coordination and leadership.
o Building institutional capability.
• Proactive Action: To help individuals avoid the worst times to travel and choose alternate city walking routes that keep them away from the most polluted places, interventions like pollution-monitoring applications should be pushed.
• It's a step in the right direction that the Graded Response Action Plan is being implemented in the Delhi-National Capital Region (NCR).
• Innovative action: In-situ pollution treatment calls for creative solutions.
• The Delhi government, for instance, is experimenting with a novel organic technique for decomposing stubble utilizing the "Pusa decomposer" from the Indian Agriculture Research Institute.
• Citizens' Obligations: The problem of air pollution persists despite countless suggestions and fixes. This occurs as a result of a lack of genuine political will and public involvement.
• Therefore, people should keep pushing for their right to safe and sustainable surroundings and insisting that governments live up to their obligations.
• Combating Injustice Given that the poor are those most at risk from air pollution, there are serious inequities at the root of the problem.
• As a result, the Polluter Pays principle must be upheld and polluting industries must pay an environmental tax.
Urbanization and rapid industrialization have benefited humanity, making life simpler and more comfortable. However, the greatest important harm posed to humanity by industry and urbanization is air pollution. Urban air pollution is more prevalent where there are denser inhabitants. Both human health and a region's climate are impacted by air pollution. More than 80% of people who reside in cities with air quality monitors are exposed to levels of air pollution that exceed WHO recommendations, with low-income cities having the highest risk of respiratory illnesses and other chronic health issues.