Air Pollution: What's In The Air We Breathe?

Air pollution is a major threat to global health and prosperity, causing around 7 or 8 million premature deaths annually. It refers to the release of pollutants into the air, which are detrimental to human health and the planet as a whole. These pollutants can be gases like ozone or nitrogen oxides, small particles like soot or other chemicals like lead. They can be released into the air by human-made sources, such as vehicles, fuel oils, and natural gas, as well as natural sources like wildfires, dust storms, and volcanic eruptions. The effects of air pollution include respiratory issues, cardiovascular problems, and other serious health conditions.

Particulate matter

The size of particulate matter is important in determining its potential health impacts. Particles with a diameter of 10 micrometers or less (often referred to as PM10) can be inhaled into the lungs and cause adverse health effects. Those with a diameter of 2.5 micrometers or less (PM2.5) are considered fine particles and pose the greatest risk to health. These fine particles can penetrate deep into the respiratory tract, reaching the lungs, and causing irritation to the eyes, nose, throat, and lungs, coughing, sneezing, and shortness of breath. Long-term exposure to PM2.5 has been linked to more serious health issues, including heart disease, asthma, reduced lung function, and increased mortality.

The health effects of particulate matter are not limited to direct inhalation. Particulate matter has also been shown to reduce visibility and affect climate change. Black carbon, a constituent of particulate matter, promotes climate warming, while other constituents like nitrate and sulfate have a cooling influence.

To protect public health, organizations like the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA) have developed guidelines and regulations to address particulate matter and air pollution. The EPA, for example, has established national and regional rules to reduce emissions of pollutants that form particulate matter, helping state and local governments meet air quality standards. Additionally, public health alerts and advisories are issued by organizations like the New York State Departments of Health and Environmental Conservation (DEC) when particle pollution levels are expected to be unhealthy, allowing individuals to take necessary precautions.

Nitrogen dioxide

NO2 is a significant air pollutant, with human-made sources in the United States emitting millions of short tons of nitrogen oxides each year. The primary sources of NO2 emissions are trucks, buses, and cars, followed by non-road diesel-powered equipment, industrial processes, and coal-fired power plants. Power plants, industrial sites, and on-road vehicles have made significant strides in reducing NO2 emissions, resulting in improved air quality across the nation. However, monitors still detect high concentrations of outdoor NO2 in large urban regions and areas near major highways.

To address the issue of nitrogen dioxide pollution, the federal Clean Air Act has implemented more protective standards, contributing to a nationwide decline in NO2 emissions. These efforts have resulted in cleaner power plants, industrial sites, and vehicles, improving air quality for many. However, there is still work to be done, as many people continue to breathe unhealthy levels of nitrogen dioxide pollution.

Ground-level ozone

Ozone itself is an atmospheric gas composed of three atoms of oxygen. While ground-level ozone is harmful, stratospheric ozone is beneficial as it forms a protective layer that shields living things from the sun's harmful ultraviolet rays. Stratospheric ozone occurs naturally in the upper atmosphere, while ground-level ozone is created by human activities such as the combustion of fossil fuels.

The concentration of ground-level ozone increases with height above sea level, reaching its maximum at the tropopause. It accounts for about 10% of total ozone in the atmosphere, while the remaining 90% is in the stratosphere. Ground-level ozone is less concentrated than stratospheric ozone, but it still has significant health effects and contributes to global warming as a greenhouse gas.

To address the issue of ground-level ozone pollution, the US Environmental Protection Agency (EPA) has implemented regulations and air quality standards to help states reduce ozone levels. These include designating areas as attainment or nonattainment based on national ambient air quality standards and providing states with guidance on improving air quality through state implementation plans (SIPs). Additionally, the EPA has established rules to reduce emissions of pollutants that form ground-level ozone, aiding state and local governments in meeting air quality standards.

Fossil fuels

The combustion of fossil fuels is a key contributor to smog, which forms when emissions interact with sunlight. Smog, or ground-level ozone, can irritate the eyes and throat and damage the lungs, especially in children, the elderly, and those who work or exercise outdoors. It can also trigger asthma attacks and worsen symptoms for individuals with asthma or allergies.

The health impacts of fossil fuel-derived PM2.5 are particularly concerning. Studies have shown that exposure to PM2.5 from fossil fuel combustion is associated with adverse health outcomes, even at low levels. The developing fetus and young children are more susceptible to the adverse effects of air pollutants from fossil fuel combustion than adults. PM2.5 has been linked to oxidative stress and inflammation in human cells, providing a foundation for chronic diseases and cancer.

According to the World Health Organization (WHO), air pollution, including that caused by fossil fuels, is responsible for millions of deaths annually. A recent study found that air pollution from fossil fuels contributes to nearly one in every five deaths worldwide, with exposure to PM2.5 from fossil fuel combustion causing approximately 8.7 million deaths globally in 2018. The health crisis caused by fossil fuel pollution is particularly severe for vulnerable populations, including children, older individuals, low-income communities, and people of color, with urban areas often bearing the brunt of the impact.

Addressing fossil fuel air pollution is crucial, and transitioning to clean, renewable energy sources is essential. A global phase-out of fossil fuels would have significant health benefits and help combat global heating. Efforts to reduce greenhouse gas emissions and invest in alternative energy sources are vital to mitigate the health and environmental consequences of fossil fuel pollution.

Wildfires

The health effects of exposure to wildfire smoke are well documented and include exacerbation of respiratory conditions such as asthma, reduced lung function, and increased risk of cardiac problems. The fine particles in wildfire smoke are responsible for most of these adverse health impacts. These particles are generated during combustion and can include a mix of hazardous substances, such as soot, smoke, and toxic chemicals. The specific composition of wildfire smoke can vary depending on the materials burned and the intensity of the fire.

Wildfire smoke is particularly concerning due to its ability to travel long distances, affecting not only those in close proximity to the fire but also individuals downwind, potentially exposing them to harmful pollutants. The frequency, intensity, and size of wildfires have been increasing, posing a growing public health problem and contributing to reduced air quality. This trend is likely to continue as the climate crisis intensifies, with warmer temperatures and increased ultraviolet radiation creating conditions that intensify smog and facilitate the spread of wildfires.

To mitigate the health risks associated with wildfire smoke, individuals are advised to stay indoors with windows and doors closed during smoky conditions. Using air conditioning with the recirculate setting turned on can also help reduce exposure to smoke particles. In areas with high levels of smoke, it is recommended to avoid outdoor activities, especially strenuous exercise, as this can increase the inhalation of harmful particles. Evacuation to areas with better air quality may be necessary, and following official evacuation orders is crucial.

While wildfires are often caused by human activities, they are also a natural source of air pollution. The smoke released during a wildfire contains a complex mixture of pollutants, some of which are known to be carcinogenic. The specific health effects of wildfire smoke exposure can vary depending on individual factors, such as age, pre-existing health conditions, and the duration and intensity of exposure. However, overall, wildfire smoke is a significant contributor to air pollution and has detrimental effects on public health and the environment.

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