Air Pollution: A Slow, Silent Killer

Air pollution is a major threat to global health and prosperity, causing more than 6.5 million deaths each year. It is a mix of hazardous substances from both human-made and natural sources. Vehicle emissions, fuel oils, natural gas, manufacturing by-products, and power generation are the primary sources of human-made air pollution. Nature also releases hazardous substances, such as smoke from wildfires, ash and gases from volcanic eruptions, and methane from decomposing organic matter. These pollutants have been linked to asthma, heart disease, lung cancer, and acute and chronic respiratory diseases. They can also cause lung tissue swelling and irritation, increase the risk of lung infections, and worsen symptoms for people with chronic obstructive pulmonary disease (COPD). Additionally, air pollution can lead to low infant birth weight, wheezing, coughing, and shortness of breath. With nine out of ten people now breathing polluted air, understanding the dangers of air pollution is crucial for safeguarding public health and mitigating its harmful impacts.

Ozone and particle pollution

Ozone, an atmospheric gas, is often referred to as smog when it is found at ground level. It is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. The essential raw ingredients needed to form ozone are nitrogen oxides (NOx), volatile organic compounds (VOCs), and sunlight. NOx is produced primarily when fossil fuels like gasoline, oil, or coal are burned, while VOCs are released into the air from some common consumer products like paint and household chemicals.

Ozone is one of the most dangerous and widespread pollutants in the United States. It is currently one of the least well-controlled pollutants in the country and is harmful to both human health and the environment. Even short-term exposure to ozone can cause greater obstruction of airways, especially for people with asthma, children, older adults, and people who are active outdoors. Ozone exposure can also cause a sore or scratchy throat, coughing, and pain when taking a deep breath. Furthermore, ozone can worsen symptoms of chronic obstructive pulmonary disease (COPD) and has been linked to the development of asthma. Strong evidence exists of the deadly impact of ozone, with research showing that the risk of premature death increases with higher levels of ozone exposure.

Particle pollution, also known as particulate matter (PM), 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. Fine particulate matter (PM 2.5) is a subset of PM that is 30 times thinner than a human hair and can be inhaled deeply into lung tissue, contributing to serious health problems. PM 2.5 has been linked to asthma-related changes in children's airways and accounts for most health effects due to air pollution in the United States.

Overall, both ozone and particle pollution pose significant risks to human health and well-being. These pollutants can lead to respiratory issues, increased susceptibility to infections, and even premature death. It is important to take measures to reduce air pollution and protect public health.

Premature death

Air pollution is a mix of hazardous substances from human-made and natural sources. It is a major threat to global health and prosperity, causing an estimated 6.5 to 7 million deaths annually worldwide. Almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants.

Outdoor air pollution in both cities and rural areas is causing fine particulate matter, which can result in strokes, heart diseases, lung cancer, and acute and chronic respiratory diseases. Indoor air pollution, caused by the use of solid fuels and kerosene in open fires and inefficient stoves, is also a major concern, particularly in low- and middle-income countries. Exposure to smoke from cooking fires causes approximately 3.2 million premature deaths each year, with women and children being the most affected.

The sources of outdoor air pollution include residential energy for cooking and heating, vehicles, power generation, agriculture/waste incineration, and industry. Policies and investments that support sustainable land use, cleaner household energy, energy-efficient housing, and better municipal waste management can help reduce air pollution and improve public health.

Respiratory issues

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, killing 6.5 to 7 million people each year. Almost all of the global population (99%) breathe air that exceeds WHO guideline limits.

Long-term exposure to air pollution can also increase the risk of developing chronic lung diseases, including asthma and COPD. Children are especially susceptible, as their lungs are still developing, and they breathe faster, taking in more polluted air. Exposure to air pollution during childhood increases the risk of developing asthma and COPD in adulthood. Studies have shown that improvements in air quality are associated with better lung function development in children.

In addition to asthma and COPD, air pollution is linked to other respiratory issues such as lung infections like bronchitis and pneumonia. It can also cause lung tissue damage and irritation, even in people with healthy lungs. Those with pre-existing respiratory diseases are at an increased risk of experiencing respiratory-related health effects due to short-term particle exposures.

Transitioning to clean energy sources and improving air quality through policy changes can help reduce the respiratory health impacts of air pollution.

Cardiovascular issues

Cardiovascular disease is a general term used to describe conditions affecting the health of the heart or blood vessels. It is the leading cause of death in the United States, with most deaths occurring in people over 65 years of age. One in three Americans has heart or blood vessel disease. Traditional risk factors for cardiovascular disease include male sex, older age, increased blood pressure, high total cholesterol, low HDL (high-density lipoprotein), and smoking. However, other factors such as diabetes, air pollution exposure, and exposure to secondhand smoke have also been found to contribute to the development of cardiovascular disease.

Recent clinical and epidemiological data suggest that air pollution is related to cardiovascular disease. Ambient air pollution (AAP) and particulate matter (PM) have been associated with adverse health effects, including respiratory and cardiovascular diseases. Fine particulate matter (PM2.5) has been found to have a stronger correlation with adverse health effects than larger particles (PM10). These fine particles can be inhaled deeply into the lungs and contribute to serious health problems. Exposure to air pollution can affect the pulmonary blood vessels and conductance and resistance arteries in the systemic circulation. The pro-constrictor/anti-vasodilator effects of air pollution in resistance arteries can lead to elevations in blood pressure, a major risk factor for cardiovascular disease.

Additionally, air pollution can worsen pre-existing cardiovascular conditions such as ischemic heart disease and heart failure. People exposed to smoke from wildland fires, which includes wildfires and prescribed fires, are at risk of various health effects due to the pollutants present in the smoke, including PM2.5. Similarly, exposure to secondhand smoke from tobacco products can lead to cardiovascular disease, heart disease, and stroke.

The sources of air pollution can be broadly categorized into natural phenomena and human activities. Natural sources include smoke from wildfires, ash and gases from volcanic eruptions, and gases emitted from decomposing organic matter. Human activities, also known as anthropogenic sources, include carbon monoxide (CO) from vehicle exhausts and sulfur dioxide (SO2) from industrial processes. As the world becomes more industrialized and populated, the air we breathe continues to grow dangerously polluted, affecting the health of millions of people.

Indoor air pollution

The health effects of indoor air pollution can be severe and include irritation of the eyes, nose, and throat, headaches, dizziness, fatigue, respiratory diseases, heart disease, and cancer. Those with pre-existing medical conditions, such as asthma, may experience asthma attacks or worsened symptoms following exposure to indoor air pollutants. Children are especially vulnerable to the effects of indoor air pollution, as their lungs are still developing. Exposure to indoor air pollution can increase their risk of developing asthma and other respiratory issues, as well as contribute to low infant birth weight and infant mortality.

The World Health Organization (WHO) has recognized the dangers of household air pollution and has issued guidelines for indoor air quality and household fuel combustion. These guidelines provide recommendations on the types of clean fuels and technologies that can be used to protect health and strategies for transitioning to cleaner household fuels and technologies.

Reducing indoor air pollution can be achieved through the adoption of cleaner fuels and technologies, such as solar, electricity, biogas, liquefied petroleum gas (LPG), natural gas, alcohol fuels, and improved biomass stoves that meet emission targets. Additionally, improving ventilation in homes can help reduce the concentration of indoor air pollutants.

The health impacts of indoor air pollution can be both immediate and long-term. Some individuals may experience immediate reactions such as eye irritation, headaches, or asthma attacks. However, long-term exposure to indoor air pollutants can lead to more severe health issues, including heart disease, respiratory diseases, and cancer, which may only become apparent years after the initial exposure.

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