Wildfires!
12/3/2018
Our nation – especially in the West – has been experiencing an increased number of wildfires. According to temperature records from the US National Oceanic and Atmospheric Administration (aka NOAA), 14 of the 20 largest wildfires in California have occurred over the past 15 years. At the same time, the western US has experienced some of its warmest temperatures on record, with 10 of the past 15 years among the warmest years on record.
Taking sides with either one of the two opposing theories for why these devastating events are occurring could unwittingly cause some political controversy. Yet the fact is wildfires are occurring at an increased frequency with greater destructive capabilities and therefore, should not be ignored. And, as any incident investigation is designed to do, once the root causes (and contributing factors) are laid out, proper corrective actions can be implemented for stopping the loss of life, property damage, as well as destroying a family’s lifetime planning of financial security.
Wildfires occur when all of the necessary elements of a fire triangle come together. That is, an ignition source that comes in contact with combustible material (aka, fuel such as vegetation), that is subjected to sufficient heat and has an adequate supply of oxygen from the ambient air. A high moisture content usually prevents ignition and slows propagation, because higher temperatures are required to evaporate any water within the material and heat the material to its flash point. Dense forests usually provide more shade, resulting in lower ambient temperatures and greater humidity, and are therefore, less susceptible to wildfires. Less dense material such as grasses and leaves are easier to ignite because they contain less water than denser material such as branches and trunks. Plants continuously lose water by evapotranspiration, but water loss is usually balanced by water absorbed from the soil, humidity, or rain. When this balance is not maintained, plants dry out and are therefore more combustible; often a consequence of droughts.
Recently, I visited California’s wine country – Napa Valley. It was only last year that this area suffered the consequence of a wildfire and caused the entire community of Napa Valley to evacuate. I was pleasantly surprised to see all the vineyards were intact, so I was compelled to ask people working at the chateaus why there wasn’t acres upon acres of scorched fields. The answer I received was consistent. That is, because the vines contain a high moisture content, the cumulative vineyards acted as a nature barrier, thereby leaving the fields protected. Thus, the fire triangle could not be completed.
Wildfires can affect local atmospheric air quality, as wildfire smoke is composed of combustion products such as carbon dioxide, carbon monoxide, water vapor, particulate matter, organic chemicals, nitrogen oxides and other compounds.
In 1997, forest fires in Indonesia were estimated to have released between 0.89 and 2.83 billion tons of CO2 into the atmosphere. That represents between 13%–40% of the annual global CO2 emissions from burning fossil fuels. Increased fire byproducts in the troposphere (the part of the Earth’s atmosphere that extends from the planet surface to approximately 6 miles high) can increase the ozone concentration beyond safe levels. Ozone or trioxygen (O3) is harmful to humans as it is a respiratory irritant. The Ozone layer – which is in the stratosphere – is a natural protective barrier that captures UV radiation from entering our atmosphere.
Wildfire emissions also contain fine particulate matter which when inhaled by humans, can cause cardiovascular and respiratory problems. Previously, prevailing scientific theory held that most particles in the stratosphere came from volcanoes, but smoke and other wildfire emissions have been detected in the lower portion of the stratosphere, which – according to scientists that hav been studying the Earth’s changing air quality – strongly suggests airborne particulate in our atmosphere is due to wildfires.
Particulate matter (PM) is a type of air pollution made up of particles of dust and liquid droplets. They are characterized into three categories based on the diameter of the particle: coarse PM, fine PM, and ultrafine PM. Coarse particles are between 2.5 micrometers and 10 micrometers, fine particles measure 0.1 to 2.5 micrometers, and ultrafine particle are less than 0.1 micrometer. Each size can enter the body through inhalation, but the PM impact on the body varies by size. Coarse particles are filtered by the upper airways and these particles can accumulate and cause sinus irritation as well as sore throat and coughing. Coarse PM typically contribute to short-term (acute) effects. Smaller particulate moves further into the respiratory system creating issues deep into the lungs and the bloodstream. In asthma patients, PM2.5 causes inflammation but also increases oxidative stress in the epithelial cells (cells that are outside of an organ, used as a protective layer), resulting in their death. The third PM type is ultra-fine PM (UFP). UFP can enter the bloodstream like PM2.5 however studies show that it migrates into the circulatory system much quicker. The inflammation and epithelial damage done by UFP has also shown to be substantial.
Current atmospheric models suggest that concentrations of sooty particles could increase absorption of incoming solar radiation during winter months by as much as 15%. Meanwhile medical studies have drawn a direct relationship of illnesses – commonly associated with exposure to PM – from wildfire smoke and include bronchitis, exacerbation of asthma and pneumonia and chronic obstructive pulmonary disease. Symptoms of these complications include wheezing and shortness of breath as well as cardiovascular symptoms which include chest pain, rapid heart rate and fatigue.
Children participating in numerous health studies were also found to have an increase in eye and respiratory symptoms. It has been demonstrated that mothers who were pregnant during the fires gave birth to babies with a slightly reduced average birth weight compared to those who were not exposed to wildfire during birth. This suggests that pregnant women may also be at greater risk to adverse effects from wildfire. Worldwide it is estimated that 339,000 people die due to the effects of wildfire smoke each year.
Whether our current increased wildfire phenomenon is attributed to manmade global climate change OR merely a natural shift in the Earth’s continuous atmospheric evolution, it is apparent that our wildfires are creating serious environmental and health concerns. And regardless of one’s political perspective, it seems that we cannot ignore the possibility of oncoming consequences.
In every walk with nature one receives far more than he seeks
John Muir