7 Impact of Wildfires on Air Quality and Human Health

As weather patterns create drier, hotter conditions, wildfire smoke has become a more pressing air quality issue. Wildfires have become more intense and frequent in recent years, particularly in the Pacific Northwest forests, wreaking havoc on communities and ecosystems. With climate change, wildfires are expected to last longer. It is critical to note that the increase in wildfires will significantly impact air quality, which is one of the primary pollutants. According to a recent study by the National Center for Atmospheric Research, an increase in pollutants from forest fires in the Pacific Northwest has started to undo a decade of air cleanup in the United States. Therefore, lowering the risk of wildfires is more crucial than ever. This chapter will start by discussing how forest fires lead to air pollution and then consider the impact air pollution has on cities and remote areas, how it travels, and threats to human health.

First and foremost, when wildfires burn, the temperature rises to dangerously high levels, amplifying air pollution. Forest fire smoke accounts for 40% of the corruption in the atmosphere from delicate particulate matter. ^[1] The burning of wildfires creates smoke containing thousands of individual compounds, including other toxic mixtures such as carbon monoxide, volatile organic compounds, carbon dioxide, hydrocarbons, and nitrogen oxides.^[2] Hundreds of millions of tons of carbon dioxide have been released into the atmosphere as a result of numerous wildfires, based on data. This amount of carbon dioxide will erode the ozone layer, which blocks ultraviolet radiation, and even change the climate once. Scientists believe that smoke from wildfires could exacerbate the melting of Arctic Sea ice since, in addition to tiny particles entering the stratosphere, it would deposit on the ice, reducing its energy to reflect solar radiation.

These compounds produced by this available combination of ingredients are distinctive. The air pollution particles are commonly referred to as PM 2.5 because they typically have a diameter of fewer than 2.5 microns. As a subset of PM, they are 30 times thinner than human hair, which can penetrate the lungs sufficiently deeply when people inhale it. Due to air pollution by wildfires, pm2.5 in the United States has the most prominent adverse effects on health. More ground-level ozone is produced as a result of the heat’s binding of smog and other pollutants.^[3] These emissions can float in the atmosphere for a long time and travel hundreds of kilometers, which include carbon dioxide, black carbon, brown carbon, and ozone, and have regional and global effects on radiation, clouds, and climate.^[4] Particularly, ozone has long been thought to be detrimental to human health and the environment because it is created at ground level by the direct emissions of toxic substances. It is the primary contributor to haze, posing a significant burden on air quality.

Toxic gases and pollutants emitted by wildfires spread quickly and can have a significant impact on urban air quality that urban areas can become engulfed in a toxic “blanket”. The entire Seattle sky was yellowish brown during the worst pollution in the Pacific Northwest. Unlike traffic emissions, wildfire smoke is more complex in composition and carries all of the harmful substances it encounters as it travels. For example, the wind blows bacteria and fungi away from surfaces such as farmland, deserts, lakes, and oceans. Wildfires accelerate the spread of these microbes, which can ascend into the atmosphere to travel worldwide. In April 2020, scientists discovered traces of bacteria and fungi in the smoke. According to the Centers for Disease Control and Prevention, the number of cases of valley fever in the US states of Arizona and California increased more than sixfold between 1998 and 2018.^[5]

Not only do these air pollutants impact cities, but they can also travel a long distance and impact areas far from the source. Long-distance transport of toxic gas and forest fire aerosol from biomass combustion will eventually have an impact on the climate and air quality in areas far from the source. For instance, the long-distance transportation of smoke from the Pacific Northwest to Colorado in the United States in 2015 resulted in poor air quality and increased metal and mineral concentrations.^[6] According to a 2018 study, wildfire smoke causes approximately 17,000 premature deaths in the United States each year, and that number is expected to double by 2100.^[7] Strong winds, dry conditions, and high temperatures were unusual in the year of the fire, all of which contributed to the rapid spread of wildfires.

Pollutants increase as air quality deteriorates, which is inevitably harmful to human health. Obviously, the dangers of wildfire smoke may extend to human skin, compromising the first line of defense against external threats. The contaminants from wildfires can have a variety of effects on both standard and eczema-prone.^[8] They typically contain unique compounds allowing them to enter cells through the skin’s external barrier, destroying gene transcription, causing oxidative stress, or causing inflammation. Thus, long-term exposure to severely polluted air causes redness and itching on the skin’s surface, as well as measles.

Furthermore, in addition to the damage to the body’s surface, the potential threat to the human body’s internal organs is noticeable. Fine smoke particles emitted by wildfires have the potential to bypass the body’s defense mechanisms and enter the bloodstream, where they can travel to other organs and increase the risk of heart attack, stroke, and breathing difficulties. Delicate particulate matter can also irritate and exacerbate asthma and other respiratory diseases by penetrating deeply into the lungs;^{[9] [10]}that wildfire smoke exposure is estimated to cause 339,000 deaths per year (260,000 to 600,000 deaths per year).^[11] According to a study published in the Journal of the American Heart Association, the body’s immune system rapidly releases immune cells that fight viruses when fine particles enter the body.^[12] However, because immune cells are unable to break down the particles, they must work harder to defeat them, resulting in increased inflammation. Forest firefighters spend months putting out these wildfires, and studies show that they are more likely to develop lung cancer and cardiovascular diseases.

Additionally, there is proof that the particles themselves have the ability to pass through capillary barriers, enter the bloodstream, and trigger an inflammatory reaction throughout the body. Inflammation can affect the lungs, kidneys, liver, and possibly even the brain. It’s worth noting that chronic inflammation can aggravate asthma and chronic obstructive pulmonary disease. Asthma rates rise, and chronic obstructive pulmonary disease may develop when more particulate pollutants build up in the alveoli, blocking gas exchange and potentially leading to pulmonary ischemia and hypoxia.^[13] Environmental Research Letters also reported that about 100,000 people died in Southeast Asia in 2015 as a result of wildfires and illegal land clearing fires in Indonesia.^[14] The most obvious response to smoke inhalation is respiratory problems, and the potential for harm is especially concerning regarding the damage wildfire smoke can do to the heart. Meanwhile, according to research, wildfire smoke PM is clearly and consistently associated with respiratory effects. Smog contains numerous carcinogens, including polycyclic aromatic hydrocarbons and benzene. Wildfires may not only cause direct harm to the human body but may also release toxic substances into the air, affecting human health on a large time and space scale. As a result, it is estimated that wildfire smoke causes a significant health burden and a high societal cost.

In conclusion, climate change is increasing the frequency and severity of wildfires. During the fire season, the constant hot and sunny conditions also contributed to the chemical reaction of increasing ozone. The chemical substances released by wildfires, such as nitrogen oxides, carbon monoxide, and various volatile organic compounds, pollute the entire atmosphere, causing air quality to deteriorate. In addition, the composition of the smog is exceptionally complex, with the majority consisting of fine particles that seriously affect people’s organs and bodily functions after inhalation. The topic of the impact of wildfires on air quality should be paid more attention to, and people must take action to prevent the deterioration of air quality.