Air Pollution: Most Critical Products And Their Impact

Air pollution is responsible for millions of premature deaths worldwide each year, with 99% of human beings currently breathing air that exceeds the World Health Organization's (WHO) guideline limits for pollutants. The health risks associated with particulate matter of less than 10 and 2.5 microns in diameter (PM10 and PM2.5) are especially well documented. PM2.5 accounts for most health effects due to air pollution in the US and is associated with an increased risk of death. The specific sources of air pollution are varied, but human-made air pollution comes primarily from vehicle emissions, fuel oils, natural gas, manufacturing by-products, and power generation. This includes ground-level ozone, various forms of carbon, nitrogen oxides, sulfur oxides, volatile organic compounds, polycyclic aromatic hydrocarbons, and fine particulate matter. The most critical air pollution products are those that are known or suspected to cause cancer or other serious health effects, such as reproductive effects, birth defects, or adverse environmental effects.

Volatile organic compounds (VOCs)

VOCs can have adverse health effects, including eye, nose, and throat irritation, headaches, loss of coordination, nausea, and damage to the liver, kidneys, or central nervous system. Some VOCs are known or suspected to cause cancer in humans and animals. The extent and nature of the health effects depend on factors such as the level of exposure and the length of time exposed. People with respiratory problems, young children, the elderly, and those with heightened sensitivity to chemicals may be more susceptible to the harmful effects of VOCs.

To reduce exposure to VOCs, it is recommended to increase ventilation and climate control by opening doors and windows and using fans to maximize the amount of fresh air. When using products that emit VOCs, it is important to increase ventilation, meet or exceed label precautions, and dispose of unused chemicals properly. It is also suggested to buy only what is needed when it comes to products containing VOCs, such as paints, solvents, adhesives, and caulks, and to consider purchasing low-VOC options.

Additionally, it is advised to identify and remove or reduce the sources of VOCs in indoor spaces. For example, unused paints and similar materials should not be stored within schools or other occupied areas. Formaldehyde, a well-known VOC, can be measured and reduced through the use of sealants on exposed surfaces. Integrated pest management techniques can also help reduce the need for pesticides, which are a source of VOCs.

Particulate matter (PM)

Of these, particles less than 2.5 micrometers in diameter, also known as PM2.5, pose the greatest risk to health. PM2.5 is associated with the greatest proportion of adverse health effects related to air pollution, both in the United States and worldwide, according to the World Health Organization's Global Burden of Disease Project. Short-term exposures to PM10 have been linked to the worsening of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), leading to hospitalization and emergency department visits.

Long-term exposure to PM2.5 has been linked to premature death, particularly in people with chronic heart or lung diseases, and reduced lung function growth in children. In California, PM2.5 exposure contributes to about 5,400 premature deaths from cardiopulmonary causes each year, according to a 2014-2016 analysis. It also contributes to about 2,800 hospitalizations for cardiovascular and respiratory diseases and about 6,700 emergency room visits for asthma annually in the state.

Fine particles are also the main cause of reduced visibility (haze) in parts of the United States, including many national parks and wilderness areas. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. PM2.5 particles come in many sizes and shapes and can be made up of hundreds of different chemicals. Some are emitted directly from sources such as construction sites, unpaved roads, fields, smokestacks, or fires. Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, vehicles, and industries.

Carbon monoxide (CO)

Breathing air with a high concentration of CO reduces the amount of oxygen transported in the bloodstream to critical organs like the heart and brain. At very high levels, which are possible indoors or in other enclosed environments, CO can cause dizziness, confusion, unconsciousness, and even death. While very high levels of CO are not likely to occur outdoors, elevated outdoor CO levels can be of particular concern for people with some types of heart disease. They are especially vulnerable to the effects of CO when exercising or under increased stress. In these situations, short-term exposure to elevated CO may result in reduced oxygen to the heart, accompanied by chest pain, also known as angina.

The Clean Air Act, established in 1970, authorises the US Environmental Protection Agency (EPA) to regulate the emissions of harmful air pollutants, including CO. The EPA sets and reviews standards for CO in outdoor air, and emissions standards for new motor vehicles under the Clean Air Act have ensured that the entire nation meets the carbon monoxide air quality standards.

To summarise, carbon monoxide (CO) is a critical air pollution product due to its detrimental effects on human health, particularly for those with heart disease, and its prevalence across the US. The EPA's efforts to regulate CO emissions and set air quality standards are crucial for protecting public health and the environment.

Ozone (O3)

However, ground-level ozone is a harmful air pollutant and is considered "bad" due to its effects on human health and the environment. It is not emitted directly into the air but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs). Cars, power plants, industrial boilers, refineries, chemical plants, and other sources emit these pollutants, which react in the presence of sunlight to form ground-level ozone.

Ozone is one of the six common air pollutants identified in the Clean Air Act, which aims to limit the levels of these pollutants in outdoor air based on health criteria. Ground-level ozone can trigger a variety of health problems, especially for children, the elderly, and people with lung diseases such as asthma. It is the main ingredient in smog and is most likely to reach unhealthy levels on hot, sunny days in urban environments.

Scientific studies have found that long-term exposure to ground-level ozone, i.e., for periods longer than eight hours, including days, months, or years, can have serious health impacts. These include increased respiratory illnesses, metabolic disorders, nervous system issues, reproductive issues, and increased respiratory and cardiovascular-related mortality. Additionally, breathing in other pollutants may increase the body's response to ground-level ozone, and ozone may enhance the body's response to allergens.

To address ground-level ozone pollution, the EPA has implemented measures such as vehicle and transportation standards, regional haze and visibility rules, and regular reviews of the National Ambient Air Quality Standards (NAAQS). States also develop State Implementation Plans (SIPs) to outline measures for improving air quality in areas that do not meet the NAAQS.

Nitrogen dioxide (NO2)

The presence of NO2 in the atmosphere has been extensively visualized and measured by NASA's Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument. TEMPO utilizes sunlight reflected and scattered off the Earth's surface, clouds, and the atmosphere to determine the concentration of NO2 and other gases. The measurements have revealed high levels of NO2 over urban areas, particularly during rush hours, and along major highways.

The health risks associated with NO2 pollution are significant. Short-term exposure to elevated levels of NO2 can irritate the respiratory system, causing inflammation and reduced lung function. Prolonged or chronic exposure to NO2 has been linked to the development and exacerbation of respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). Vulnerable populations, including children, the elderly, and individuals with pre-existing respiratory issues, are at an even higher risk of adverse health effects.

Additionally, NO2 pollution has ecological consequences. It contributes to the formation of ground-level ozone, which can damage vegetation and reduce crop yields. NO2 also plays a role in the creation of particulate matter pollution, which can have far-reaching environmental impacts, including reduced visibility, ecological disruption, and climate change.

Addressing NO2 pollution requires a multifaceted approach. Regulations and emissions standards for vehicles, power plants, and industrial facilities have proven effective in reducing NO2 levels. Transitioning to cleaner energy sources, such as renewable and alternative fuels, can also help minimize NO2 emissions. Furthermore, promoting sustainable practices, such as encouraging the use of public transportation, carpooling, and reducing idle vehicle time, can contribute to decreasing NO2 pollution.

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