Air Pollution And Smog: What's The Link?

Smog is a type of air pollution that is harmful to human health and the environment. It is formed by a combination of air pollutants, including nitrogen oxides, sulphur dioxide, carbon monoxide, and volatile organic compounds, which interact with sunlight to create ground-level ozone. This ground-level ozone, along with particulate matter, is the main component of smog and is responsible for the respiratory issues associated with it. While smog is influenced by weather conditions, it is predominantly caused by human activities, such as the burning of fossil fuels and vehicle emissions, and can have severe health impacts, particularly in densely populated cities.

Transportation and air pollution

Transportation is a significant contributor to air pollution, which in turn causes smog. Smog is formed when chemical pollutants, such as nitrogen oxides and volatile organic compounds (VOCs), are baked by the sun and undergo chemical reactions. These pollutants are emitted from vehicles, particularly those powered by fossil fuels, and can have detrimental effects on human health and the environment.

The transportation sector, including cars, trucks, and buses, as well as ships, trains, and planes, accounts for a substantial portion of heat-trapping gas emissions. In the United States, transportation emits more than half of the nitrogen oxides in the air and contributes to global warming. Pollutants from vehicle exhausts have been linked to adverse impacts on various organ systems in the body and can even lead to premature death. Exposure to transportation pollution disproportionately affects certain racial and ethnic groups, with higher concentrations experienced by Asian Americans, Black people, and Latino people.

To address transportation-related air pollution, various initiatives and programs have been implemented. The U.S. Environmental Protection Agency (EPA) sets national programs and standards for fuels and vehicles to reduce emissions and improve air quality. The EPA's stringent emissions standards for passenger vehicles and heavy-duty diesel vehicles aim to reduce pollutants such as nitrogen oxides and sulfur. The Diesel Emissions Act Reduction program provides funding for projects that reduce harmful emissions from diesel engines, and the Clean School Bus Program aims to replace existing school buses with zero-emission or low-emission models.

Additionally, the International Maritime Organization (IMO) has designated coastal areas of North America as an Emission Control Area (ECA), imposing stricter emissions and fuel standards on large ocean-going vessels. The Ports Initiative aims to develop sustainable port strategies, while the SmartWay program helps the freight transportation industry improve supply chain efficiency to reduce air pollution. Communities are also taking action by expanding bike lanes and promoting walking to reduce vehicle emissions and improve air quality.

Transitioning to zero-emission vehicles, such as electric cars, trucks, and buses, is crucial to curbing transportation-related air pollution. This includes integrating electric vehicle fleets, such as in China, and promoting sustainable transportation options through equity-centered programs. By reducing emissions from the transportation sector, we can improve air quality, protect public health, and mitigate the impacts of climate change.

Photochemical reactions

Smog is a combination of smoke and fog. It is mainly composed of ground-level ozone and particulate matter. While smog was historically the result of soot particles from sources like fires and combustion engines combining with water vapour in the air, today it is usually produced photochemically.

Photochemical smog is caused by chemical pollutants in the air, such as nitrogen oxides and volatile organic compounds (VOCs) from automobile exhausts, reacting with sunlight. VOCs are responsible for the generation of photochemical smog due to their potential for creating photochemical ozone (POCP). POCP is produced when VOCs react with NOx under solar radiation, resulting in tropospheric ozone.

Nitrogen oxides are emitted into the air as pollutants from internal combustion engines. They absorb the visible or ultraviolet energy of sunlight, forming nitric oxide (NO) and free atoms of oxygen (O). These combine with molecular oxygen (O2) to form ozone (O3). In the presence of hydrocarbons, certain other organic compounds, and sunlight, various chemical reactions take place to form photochemical smog.

The major undesirable components of photochemical smog are nitrogen dioxide (NO2), ozone (O3), peroxyacetyl nitrate (PAN), and chemical compounds that contain the –CHO group (aldehydes). These components have various adverse effects on human health, including eye irritation, respiratory ailments, and reduced visibility. They can also cause plant damage and irritate the eyes.

Health problems caused by smog

Smog is a mixture of smoke and fog, formed when water vapour in the air condenses on small particles of soot. It is mainly composed of ground-level ozone and particulate matter. These particles are emitted during combustion, for example, from fires or diesel engines, and can also form in the atmosphere as a result of chemical reactions involving volatile organic compounds (VOCs).

Smog is a significant health hazard, causing a range of problems, particularly related to the respiratory and cardiovascular systems. Here are some of the key health issues caused by smog:

Respiratory Problems

Breathing in smog can irritate the eyes, nose, and throat, causing coughing and shortness of breath. The particulate matter in smog can be easily inhaled and can become embedded in the lungs, causing or aggravating respiratory conditions such as asthma, bronchitis, and bronchiolitis. Studies have shown that children living near busy roads with high levels of air pollution are more likely to develop asthma and bronchitis in adulthood.

Cardiovascular Issues

Smog exposure can increase the risk of cardiovascular problems, including heart attacks and stroke. The ozone and particulate matter in smog can affect people with existing heart conditions, and even those with healthy lungs and hearts can experience irritation and swelling in the lungs.

Lung Cancer

Long-term exposure to smog has been linked to an increased risk of lung cancer. The World Health Organization (WHO) classified air pollution, including smog, as a human carcinogen in 2013.

Neurological Disorders

Smog has been associated with neurological issues, including potential genetic mutations and cognitive and emotional problems in children.

Eye Irritation

The particles in smog can cause eye irritation, a common complaint among those exposed to smog.

Premature Death

Both short-term and long-term exposure to smog have been linked to premature death. The high mortality rates associated with COVID-19 in highly polluted regions provide further evidence of the deadly impact of air pollution.

The health impacts of smog are serious and far-reaching, affecting people of all ages but particularly vulnerable groups such as children and those with pre-existing health conditions. Efforts to reduce air pollution, such as implementing emissions standards and promoting clean technologies, are crucial to mitigate the harmful effects of smog on human health.

The origin of the word smog

The word "smog" is a combination of the words "smoke" and "fog". It was coined in the early 20th century, specifically in 1905 by H.A. Des Voeux, in his paper "Fog and Smoke" for a meeting of the Public Health Congress. The term was used to describe the atmospheric conditions over many British towns, and more specifically, over London.

The 26 July 1905 edition of the London newspaper Daily Graphic quoted Des Voeux:

> "He said it required no science to see that there was something produced in great cities which was not found in the country, and that was smoky fog, or what was known as 'smog'.

The following day, the newspaper also stated that "Dr. Des Voeux did a public service in coining a new word for the London fog." However, the term appeared twenty-five years earlier than Voeux's paper, in the Santa Cruz & Monterey Illustrated Handbook, published in 1880. It also appeared in print in a column quoting from the book in the 3 July 1880 edition of the Santa Cruz Weekly Sentinel. On 17 December 1881, in the publication Sporting Times, the author claims to have invented the word:

> "The 'Smog' – a word I have invented, combined of smoke and fog, to designate the London atmosphere..."

The word was intended to refer to what was sometimes known as "pea soup fog", a familiar and serious problem in London from the 19th century to the mid-20th century. This kind of visible air pollution is composed of nitrogen oxides, sulfur oxide, ozone, smoke, and other particulates.

How to reduce air pollution

Smog is mainly composed of ground-level ozone and particulate matter, which is emitted during combustion, for example, from fires or diesel engines. It is also formed in the atmosphere as a result of chemical reactions involving volatile organic compounds (VOCs).

Reduce Vehicle Emissions

• Opt for walking or riding a bike when possible.
• When purchasing a new vehicle, consider vehicles that run efficiently and provide the best gas mileage.
• Limit idling your vehicle to no more than 30 seconds.
• Keep your car well-maintained and ensure its emissions control systems are functioning properly.
• Keep your tires inflated to the suggested amount.
• Fuel your vehicle in the early morning or late at night, as this helps reduce air pollution during the hottest parts of the day.
• Consider carpooling or using public transportation to reduce the number of vehicles on the road.

Reduce Energy Consumption

• Turn off electrical appliances and lights when not in use.
• Choose energy-efficient appliances, light bulbs, and heating/cooling systems.
• Get an energy audit and follow the recommended steps to improve energy efficiency.
• Reduce energy consumption by opting for natural lighting and ventilation, such as opening blinds and windows.
• Wash laundry in cold water and air dry whenever possible.
• Add insulation to your home to reduce the need for heating or cooling.

Reduce Use of Toxic Chemicals

• Eliminate the use of toxic chemicals at home and opt for natural substitutes.
• Avoid burning trash or waste, as it releases toxic pollutants into the air.
• Use an EPA-approved wood-burning stove or fireplace insert.
• Limit backyard fires, especially in urban areas, as smoke can negatively impact the health of those with asthma and other lung conditions.

Plant and Care for Trees

• Trees act as natural air filters, absorbing carbon dioxide and releasing oxygen into the atmosphere.
• They also provide shade, reducing the need for air conditioning.

Support Environmental Initiatives

• Advocate for policies and initiatives that aim to reduce air pollution, such as emission control standards and clean vehicle technologies.
• Support local businesses, city offices, and schools in their efforts to become more sustainable.
• Participate in recycling programs and encourage others to do the same.

Frequently asked questions