Air Pollution's Origin Story: A Historical Perspective

Air pollution has been a concern since the time of Hippocrates, around 400 BC, and the problem has only grown since. The air we breathe contains harmful solid and liquid particles and gases, which can have a detrimental effect on the health of humans, animals and plants, as well as the environment. The burning of fossil fuels, such as coal, natural gas and oil, is a major contributor to air pollution, with vehicles, planes, power plants and factories all releasing harmful emissions. While air pollution is a global issue, it is more common in large cities, where emissions from multiple sources are concentrated.

Burning fossil fuels

The burning of fossil fuels is a significant contributor to air pollution. Fossil fuels include coal, natural gas, and oil, and they are burned to generate energy. Since the invention of the first coal-fired steam engines in the 1700s, our burning of fossil fuels has steadily increased. Today, we burn over 4,000 times more fossil fuels per year than we did in 1776.

The combustion of fossil fuels releases various pollutants into the atmosphere, including solid and liquid particles, certain gases, and greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O). These emissions can remain in the atmosphere for decades to centuries, intensifying the greenhouse effect and contributing to climate change.

One of the primary ways in which burning fossil fuels contributes to air pollution is by releasing nitrogen oxides into the atmosphere. Nitrogen is the most abundant element in the air and is essential for plant and animal life. However, when fossil fuels are burned, they emit nitrogen oxides that contribute to the formation of smog and acid rain. Acid rain occurs when nitrogen oxides and sulfur dioxide mix with water and oxygen in the atmosphere, causing harm to plants, water bodies, crops, and even buildings.

Additionally, the burning of fossil fuels emits airborne particles such as soot, which increases the reflectivity of the atmosphere and has a slight cooling effect. However, when these particles settle on snow, they absorb more sunlight due to their dark colour, accelerating snow and ice melt. The combustion of fossil fuels also releases harmful pollutants that can directly affect human health. Long-term exposure to air pollution has been linked to respiratory diseases and other health issues in children and adults.

Moreover, the burning of fossil fuels is not limited to power generation and transportation. It also includes industrial processes, home heating, and cooking. Large cities, particularly in developing nations, tend to have worse air pollution due to fewer regulations, limited financial resources, and a lack of access to cleaner fuels. However, cities in developed nations, such as Italy and Poland, continue to face air pollution challenges as well.

Industrial Revolution

The Industrial Revolution, which began in Great Britain in the late eighteenth century, was a period of rapid economic growth and manufacturing-based economic development. This period saw the advent of manufacturing based on heavy industrial machinery, which improved efficiency and output. Steam power, for example, allowed for the creation of a semi-automated factory system, which meant that goods could be mass-produced instead of being made by hand.

However, powering the heavy machinery central to industrialization required vast amounts of energy, primarily derived from fossil fuels like coal. This marked the start of our intensive use of fossil fuels, which is the driving force behind climate change. The Industrial Revolution's environmental impact was profound, causing a sharp increase in carbon emissions and harmful environmental pollution. The widespread use of coal and later oil-powered machinery led to a rapid increase in carbon emissions, with Europe and North America dominating emissions and suffering the majority of the adverse effects.

The Industrial Revolution also contributed to environmental degradation, the depletion of natural resources, water pollution, and urban overcrowding. The rapid industrial growth outpaced the ability to manage waste and emissions, resulting in long-term damage to both the environment and public well-being. The focus on productivity and economic growth came at the expense of environmental sustainability, setting in motion a pattern of unchecked resource exploitation and high emissions that continue today.

The Industrial Revolution accelerated the magnitude of emissions of primary pollutants and the geographical spread of contributing countries. As a result, highly polluted cities became a defining issue, culminating in the Great Smog of London in 1952. The environmental impact of the Industrial Revolution included deforestation, loss of biodiversity, and the continuous rise in greenhouse gases, which remain major global challenges.

Wildfires and volcanoes

Volcanoes are geographical formations that release lava, small rocks, steam, gases, and ash onto the Earth's surface. Volcanic eruptions can result in the release of harmful particles, including volcanic gases and ash, into the air. Volcanic gases are often odorless and invisible, making it difficult for people to avoid exposure. Inhaling these gases and ash can be harmful to one's health, potentially exacerbating asthma symptoms and causing irritation to the airways. Additionally, volcanoes contribute to the release of carbon dioxide, a greenhouse gas, into the atmosphere. According to the United States Geological Survey, a volcanic eruption can release between 8,000 and 30,000 metric tonnes of carbon dioxide per day.

Cigarettes and vapes

Vapes, too, are a rising environmental threat. The vape market is mainly owned by the tobacco industry, and the devices produce emissions that contribute to air pollution and climate change. The aerosol from e-cigarettes contains ultrafine particles that can enter the lungs and bloodstream, and the solvents produce volatile organic compounds that create ozone. Studies show that e-cigarette vapour contains toxic chemicals like formaldehyde, acetaldehyde, and acrolein. The supply chain for the e-cigarette industry also contributes to a sizable carbon footprint.

The waste from vapes is a particular cause for concern. Globally, close to 844 million vapes are dumped yearly, with 5 million single-use vapes discarded weekly in the UK alone. Vapes are considered hazardous waste due to their nicotine and battery content. E-cigarette waste contains metals, circuitries, disposable plastic cartridges, batteries, and toxic chemicals in e-liquids that can leak toxic materials into the soil and groundwater if not properly disposed of. There are currently no legal ways to recycle disposable e-cigarettes in some countries, and manufacturers do not provide guidance to consumers on how to dispose of used devices. The batteries and circuit boards in dumped vapes can leach toxic heavy metals like lead into the soil and groundwater.

The use of e-cigarettes in indoor spaces, such as vape shops, has been shown to increase particle levels and impair indoor air quality. Studies have found high concentrations of hazardous pollutants in the air of vape shops and vaping conventions, including particulate matter (PM10), total volatile organic compounds (TVOCs), CO2, NO2, and airborne nicotine.

Urbanisation

Urban areas are centres of resource utilisation and major contributors to air pollutant and greenhouse gas emissions. Cities consume about 75% of global primary energy and emit 50-60% of the world's total greenhouse gases. Urbanisation increases urban land use and anthropogenic emissions, affecting the concentrations and health risks associated with air pollutants. The health risks related to urbanisation are rarely estimated, particularly in cities with complex terrain.

The effects of urbanisation on air quality have been studied in various cities, with research focusing on the impact of urban landscape patterns and the developmental stage of cities. The spatial connectedness of urban patches in larger cities is positively associated with long-term increases in fine particulate matter (PM2.5) levels. However, the impact of urban fragmentation on air quality is controversial. Compact urban development has proven effective in mitigating air pollution in some cities, as it promotes high residential density, reduces car dependence, and increases the usage of public transit and walking.

Air pollution in urban areas is influenced by various factors, including emissions from multiple sources, meteorology, and physicochemical transformations. The concentration of emissions in large cities, especially those in economically developing nations, contributes to higher levels of air pollution. Mountains or tall buildings can further exacerbate the problem by preventing the dispersion of pollutants, leading to the formation of smog. The health consequences of air pollution in urban areas are significant, with pollutants such as PM2.5 and ozone (O3) contributing to premature mortality and various diseases, including cardiovascular and respiratory illnesses.

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