Air Pollution: Understanding The Severity Of Contamination

Air pollution is a pressing global issue that poses significant risks to human health and the environment. According to the World Health Organization (WHO), air pollution is responsible for approximately seven million deaths worldwide annually, with 99% of the global population breathing air that exceeds WHO guideline limits. The major sources of air pollution include household combustion devices, motor vehicles, industrial facilities, and forest fires, releasing various pollutants such as particulate matter (PM), carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. These pollutants have detrimental effects on respiratory health and are linked to increased morbidity and mortality rates. Addressing air pollution requires concerted efforts by policymakers and individuals to implement cleaner technologies, improve energy efficiency, and transition to sustainable practices. Understanding the levels of air pollution and their impacts is crucial for mitigating health risks and promoting a sustainable future.

Air Quality Index (AQI)

Air pollution is a major environmental health problem affecting everyone in low-, middle-, and high-income countries. In 2019, 99% of the world’s population was living in places where the WHO air quality guidelines levels were not met. The combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually.

To address this, the Environmental Protection Agency (EPA) developed the Air Quality Index (AQI) to inform the public about the health effects of the five most common air pollutants and how to avoid them. The AQI is a system used to warn the public when air pollution is dangerous. It tracks ozone (smog) and particle pollution (tiny particles from smoke, power plants, factories, vehicle exhaust, and other sources), as well as four other widespread air pollutants. The AQI scale used for indexing real-time pollution is based on the latest US EPA standard, using the Instant Cast reporting formula.

The AQI breaks air pollution levels into six colour-coded categories, each with a name, a corresponding colour, and advice. AQI values at or below 100 are considered satisfactory for almost everyone. When AQI values are above 100, air quality is unhealthy, initially for certain sensitive groups of people, then for everyone as AQI values increase. For example, an AQI value of 50 or below represents good air quality, while an AQI value over 300 represents hazardous air quality.

Newspapers, radio, television, and websites report AQI levels year-round. Keeping track of the current air quality information in your area can help you take steps to protect yourself, your children, and others from unhealthy levels of air pollution. For example, if the day's air quality forecast is code orange or worse, adjust your plans for the day. Avoid long periods of outdoor activity. Stay away from high-traffic areas, and do not exercise near those areas. On worse air quality days, everyone should try to stay indoors as much as possible.

Particulate matter (PM)

PM2.5 refers to fine inhalable particles with diameters that are generally 2.5 micrometers and smaller. These particles are so small that they can be inhaled and cause serious health problems. They can get deep into your lungs, and some may even enter your bloodstream. PM2.5 is the main cause of reduced visibility (haze) in parts of the United States, including national parks and wilderness areas. It also affects visibility by altering how light is absorbed and scattered in the atmosphere.

PM10 refers to particles with a diameter of 10 micrometers or less, which are also inhalable and can induce adverse health effects. PM2.5 is a component of PM10, and they often derive from different emission sources and have distinct chemical compositions. While the health effects of long-term PM10 exposure are less clear, several studies suggest a link to respiratory mortality.

The Air Quality Index (AQI) is used to inform the public about dangerous levels of air pollution, including particle pollution. The AQI translates air quality data into numbers and colours, helping individuals understand when to take action to protect their health. For example, on high pollution days, individuals can avoid spending extended periods outdoors, especially in high-traffic areas.

Greenhouse gases

The primary greenhouse gases include water vapour, carbon dioxide (CO2), methane, nitrous oxide, and ozone. Water vapour is the most abundant greenhouse gas, accounting for about half of the greenhouse effect. Carbon dioxide, released through the burning of fossil fuels, solid waste, trees, and certain industrial processes, is the second most abundant and persistent greenhouse gas, with human activities increasing its atmospheric concentration by over 50% since the Industrial Revolution. Methane, produced by agriculture, fossil fuel production, waste, and other sources, has increased by 150% due to human activities.

In addition to these primary greenhouse gases, there are other potent greenhouse gases known as fluorinated gases. These include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride. Fluorinated gases are synthetic and emitted from a range of household, commercial, and industrial applications. While they are present in smaller concentrations compared to other greenhouse gases, they are extremely effective at trapping heat. For example, SF6 has a Global Warming Potential (GWP) 23,000 times greater than CO2.

The concentration of greenhouse gases in the atmosphere is typically measured in parts per million, parts per billion, and even parts per trillion. Higher emissions lead to increased atmospheric concentrations, which enhance the greenhouse effect and contribute to global warming and climate change. This phenomenon is known as the enhanced greenhouse effect, resulting from anthropogenic changes to the natural greenhouse gas balance. The warming effect of each greenhouse gas is quantified using GWP, which measures the amount of energy absorbed by one ton of a gas over a 100-year period relative to carbon dioxide. Gases with higher GWP values contribute more to global warming.

Health risks

Air pollution is a major environmental health problem affecting individuals in low-, middle-, and high-income countries. In 2019, 99% of the world's population lived in areas that did not meet the World Health Organization's (WHO) air quality guidelines. According to the WHO, air pollution is associated with 6.7 million premature deaths annually, with 4.2 million of these deaths linked directly to ambient (outdoor) air pollution.

The health risks of air pollution are extensive and affect individuals of all ages. Short-term exposure to higher levels of outdoor air pollution is associated with reduced lung function, asthma, cardiac problems, emergency department visits, and hospital admissions. Long-term exposure to air pollution has been linked to an increased risk of stroke, heart disease, chronic obstructive pulmonary disease (COPD), and cancer. Fine particulate matter in the air can impair blood vessel function and speed up the calcification of arteries, increasing the risk of cardiovascular disease. Air pollution has also been linked to an increased risk of respiratory infections, with children living in high ozone communities being more likely to develop asthma and those exposed to high levels of air pollutants being more prone to developing bronchitis symptoms in adulthood.

Pregnant women exposed to air pollution face an increased risk of dangerous changes in blood pressure, known as hypertensive disorders, which are a leading cause of pre-term birth, low birth weight, and maternal and fetal illness and death. Research has also found a link between living near major roadways and an increased risk of breast cancer in women. Furthermore, occupational exposure to benzene, an industrial chemical and component of gasoline, can cause leukemia and is associated with non-Hodgkin's Lymphoma.

Air pollution also disproportionately affects certain demographic groups. People of color are more likely to be exposed to air pollution and suffer adverse health effects due to systemic racism and residential segregation, which have historically confined people of color to lower-income areas with higher pollution levels. Additionally, people of color have higher rates of chronic conditions, such as asthma and diabetes, that increase susceptibility to the health impacts of air pollution. Low-income individuals are also at higher risk due to their proximity to pollution sources and limited resources for relocation or access to quality healthcare.

Interventions and policies

Energy and Industry Interventions: Phasing out the use of coal and other fossil fuels, such as lignite and tar products, for power production is crucial. This can be achieved by transitioning to renewable energy sources like solar, wind, and hydropower. Additionally, implementing clean technologies to reduce industrial smokestack emissions and improving waste management practices, such as capturing methane gas from waste sites for use as biogas, are effective measures.

Transportation Policies: Shifting towards cleaner modes of transportation is essential. This includes promoting the use of electric vehicles, low-emissions vehicles, and cleaner heavy-duty diesel vehicles. Prioritizing rapid urban transit, walking, and cycling networks, as well as improving interurban rail freight and passenger travel, can significantly reduce vehicle emissions.

Urban Planning Initiatives: Redesigning urban areas to promote walkability and compact, energy-efficient cities is important. This includes improving the energy efficiency of buildings and increasing green spaces. Implementing Low Emission Zones (LEZ) programs, as seen in London, Tokyo, and Sweden, can effectively reduce air and noise pollution by charging the most polluting vehicles a daily fee to enter these zones.

Power Generation and Agriculture Policies: Increasing the use of low-emissions fuels and renewable, combustion-free power sources is crucial. Additionally, improving waste management in agricultural practices and capturing methane emissions can help reduce air pollution from these sectors.

Individual Actions: While source controls are the most effective, individuals can also take proactive measures to reduce exposure. This includes staying indoors, using respirators or face masks, and filtering indoor air with portable air cleaners.

These interventions and policies offer a comprehensive approach to addressing air pollution, requiring collaboration between local, national, and regional policymakers across various sectors, including energy, transport, waste management, urban planning, and agriculture.

Frequently asked questions