Air Pollution: What's Lurking In Your Home?

Air pollution is a significant global issue, causing an estimated 6.5 to 8 million premature deaths annually and posing a major threat to human health, prosperity, and the environment. It refers to the release of harmful substances, including solid and liquid particles, gases, and chemicals, into the air. These pollutants can be released from various sources, such as human-made and natural sources, with the burning of fossil fuels, vehicle emissions, industrial processes, and natural disasters like wildfires, all contributing to the degradation of air quality. Indoor air pollution, often caused by the use of biomass for cooking and heating, and outdoor air pollution, arising from industrial processes and the burning of fossil fuels, both have detrimental effects on human health and the planet.

Indoor air pollution: caused by biomass fuel, such as wood, used for cooking and heating

Air pollution is a mix of hazardous substances from both human-made and natural sources. It is a major threat to global health and prosperity and is the world's fourth-largest risk factor for premature death. According to the World Health Organization (WHO), indoor and outdoor air pollution is responsible for nearly seven million deaths worldwide each year.

Indoor air pollution is a significant contributor to this figure, with around 2.4 billion people exposed to dangerous levels of indoor air pollution. One major source of indoor air pollution is the burning of biomass fuel, such as wood, for cooking and heating. Biomass fuel refers to any organic material burned for energy, including wood, charcoal, dung, and crop residues. In developing countries, biomass fuel can account for more than half of domestic energy use, and in lower-income countries, this figure can rise to 95%.

The use of biomass fuel for cooking and heating has been linked to increased levels of indoor air pollution and a range of negative health outcomes. Studies have found associations between exposure to biomass fuel smoke and an increased risk of respiratory infections, inflammatory lung conditions, cardiac events, stroke, eye disease, tuberculosis, cancer, and hospital admissions. Long-term exposure to biomass fuel smoke has also been linked to the development of lung cancer, with several chemicals with Group I carcinogen status found in wood smoke.

The particulate matter (PM) produced by burning biomass fuel can be especially harmful. PM2.5, a fine particulate matter that is 30 times thinner than a human hair, can be inhaled deeply into the lung tissue and contribute to serious health problems. High concentrations of PM2.5 are often found in indoor kitchens when cooking with solid fuels like wood, and can cause eye and throat irritation.

The impact of indoor air pollution from biomass fuel is particularly pronounced in the developing world, where it is a major health concern. The poorest and most vulnerable populations often bear the greatest health impacts of air pollution, as they are more likely to rely on biomass fuel for their energy needs. Initiatives to promote cleaner household energy sources and improve access to modern fuels can help reduce indoor air pollution levels and mitigate the associated health risks.

Outdoor air pollution: caused by industrial processes, burning fossil fuels, waste management, and agriculture

Outdoor air pollution is a major environmental health problem affecting everyone worldwide. It is caused by various human activities, including industrial processes, burning fossil fuels, waste management practices, and agriculture. According to the World Health Organization (WHO), outdoor air pollution is responsible for millions of premature deaths globally each year.

Industrial processes contribute significantly to outdoor air pollution. The combustion of fuels in various industries releases nitrogen dioxide (NO2), a common air pollutant. Industries burning fossil fuels like coal and oil also emit sulfur dioxide (SO2), a colourless gas with a sharp odour. Additionally, industrial smokestacks release harmful pollutants into the atmosphere, impacting both human health and the environment.

Burning fossil fuels is a major contributor to outdoor air pollution. The combustion of fossil fuels, such as gasoline, diesel, and coal, releases fine particulate matter, known as PM 2.5, which includes soot and other harmful chemicals and gases. Exposure to PM 2.5 has been linked to millions of premature deaths worldwide, with higher concentrations found in major cities like Beijing, exceeding World Health Organization standards.

Ineffective waste management practices also contribute to outdoor air pollution. Open dumping and burning of waste release harmful substances into the air, making it difficult to breathe and exacerbating health issues. Improper waste management, which affects about 50% of the world's waste, negatively impacts both human health and the environment.

Agriculture, a significant contributor to outdoor air pollution, is affected by air pollution as well. Ground-level ozone pollution, created by fuel burning and chemical use in agriculture, is estimated to reduce staple crop yields globally. Additionally, climate change, influenced by air pollution, impacts agricultural productivity, particularly in the tropics and subtropics, threatening food security and livelihoods for those dependent on agriculture.

Addressing outdoor air pollution requires concerted efforts and policy interventions at local, national, and regional levels. Implementing clean technologies, improving waste management practices, transitioning to cleaner energy sources, and promoting sustainable agricultural practices can help mitigate the impacts of outdoor air pollution on human health, the environment, and various economic sectors.

Particulate matter: tiny particles of chemicals, 30 times thinner than a human hair, that can be inhaled into lung tissue

Particulate matter, or PM, is a term used to describe a complex mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings. These particles vary widely in size, shape, and chemical composition, and may contain inorganic ions, metallic compounds, elemental carbon, organic compounds, and compounds from the earth’s crust.

PM is not a single pollutant but rather a mixture of many chemical species. It is composed of chemicals such as sulfates, nitrates, carbon, or mineral dusts. Vehicle and industrial emissions from fossil fuel combustion, cigarette smoke, and burning organic matter, such as wildfires, all contain PM.

A subset of PM, fine particulate matter (PM 2.5), is 30 times thinner than a human hair. These particles are so small that they can be inhaled deeply into the lung tissue and contribute to serious health problems. PM2.5 accounts for most health effects due to air pollution in the United States. PM2.5 is more likely to travel into and deposit on the surface of the deeper parts of the lung, while larger particles (PM10) are more likely to deposit on the surfaces of the larger airways of the upper region of the lung.

The health impacts of PM2.5 exposure include premature mortality, increased hospital admissions for heart or lung causes, acute and chronic bronchitis, asthma attacks, emergency room visits, respiratory symptoms, and restricted activity days. These adverse effects have been reported primarily in infants, children, and older adults with pre-existing heart or lung diseases. Exposure to the air pollutant PM2.5 is associated with an increased risk of death.

Greenhouse gases: gases that trap heat in the atmosphere, such as carbon dioxide and methane

Greenhouse gases are gases that trap heat in the Earth's atmosphere, maintaining a temperature of approximately 15°C (59°F) and making the planet habitable. The primary greenhouse gases are carbon dioxide, methane, nitrous oxide, and water vapour. Other greenhouse gases include fluorinated gases, such as hydrofluorocarbons, which are used as substitutes for stratospheric ozone-depleting substances.

Carbon dioxide (CO2) is a significant contributor to the greenhouse effect. It enters the atmosphere through the burning of fossil fuels, solid waste, trees, and other biological materials, as well as certain chemical reactions like cement production. Human activities, particularly the burning of fossil fuels, have disrupted the Earth's energy balance, leading to increased carbon dioxide levels in the atmosphere and oceans. Since 1750, human activities have released nearly 1.5 trillion tons of carbon dioxide into the Earth's atmosphere. Carbon dioxide is removed from the atmosphere through absorption by "carbon sinks" such as forests, soil, and the ocean.

Methane (CH4) is another crucial greenhouse gas. It is emitted during the production and transport of coal, natural gas, and oil. Additionally, methane emissions arise from livestock and other agricultural practices, land use, and the decay of organic waste in municipal solid waste landfills. Methane is a potent greenhouse gas, with a higher global warming potential (GWP) than carbon dioxide, meaning it traps more heat per unit mass.

The concentration of greenhouse gases in the atmosphere has been increasing, amplifying the planet's natural greenhouse effect and contributing to global warming and climate change. This, in turn, has led to air pollution, which poses a significant threat to human health and the environment. Air pollution is associated with various health issues, including oxidative stress, inflammation, chronic diseases, and cancer. It is responsible for millions of premature deaths annually, with indoor and outdoor air pollution causing approximately 6.7 million deaths worldwide each year.

To mitigate the impacts of greenhouse gases and air pollution, policies and interventions that support sustainable land use, cleaner energy and transport, energy-efficient housing, improved waste management, and the reduction of fossil fuel emissions are essential. These measures not only improve air quality but also contribute to the mitigation of climate change and the improvement of public health.

Health effects: air pollution is linked to respiratory and cardiovascular issues, as well as an increased risk of cancer

Air pollution is a mix of hazardous substances from both human-made and natural sources. It is a major threat to global health and prosperity, causing more than 6.5 million deaths each year worldwide. According to the World Health Organization (WHO), indoor and outdoor air pollution is responsible for nearly seven million deaths globally each year.

The health effects of air pollution are wide-ranging and severe. One of the most significant impacts is on the respiratory system. Air pollution can cause a range of respiratory issues, including asthma, bronchitis, chronic obstructive pulmonary disease (COPD), and respiratory infections. Ozone, a major component of smog, is a powerful lung irritant that can cause chest pain, coughing, and throat irritation, even in the short term. Fine particulate matter (PM2.5) can penetrate deep into the lungs, causing serious health problems. Nitrogen oxides (NOx) and sulfur oxides (SOx), produced primarily by the transportation sector, can worsen asthma and increase susceptibility to respiratory infections.

Air pollution is also linked to an increased risk of cardiovascular issues. Tiny particles in pollution can travel to the blood vessels and cause inflammation, increasing the risk of heart disease, heart attacks, irregular heartbeat (arrhythmia), and heart failure. Ozone exposure has also been linked to decreased lung function, which can impact the cardiovascular system. Additionally, air pollution has been associated with an increased risk of stroke, with certain components of air pollution, such as ozone, nitrogen dioxide, and sulfur dioxide, being particularly deadly.

Furthermore, air pollution has been classified as a human carcinogen by the International Agency for Research on Cancer of the World Health Organization (WHO). Exposure to air pollution has been linked to an increased risk of lung cancer, with higher levels of PM2.5 exposure contributing significantly to this risk. Black carbon, a component of particulate matter, has also been associated with a variety of cancer types.

The effects of air pollution are not limited to physical health. Studies have shown a strong link between air quality and mental health. People living in areas with poor air quality have higher rates of bipolar disorder and major depression. Additionally, air pollution can impact brain development in children, with traffic-related air pollution being linked to slower brain and behavior development.

Frequently asked questions