Forest Fire Flames and Smoke: Double the Trouble

As of Friday November 16, 2018, California was home to the three most polluted cities in the world. These three cities – San Francisco, Stockton, and Sacramento – topped the world’s chart of polluted cities as a result of the infiltrating smoke produced from the nearby, devastating Camp Fire. To date, the Camp Fire is the deadliest fire in California history and has burned over 170,000 acres of land, roughly the size of New York City. Over its rampage it has destroyed immense areas of California’s wildlife and burned down over 17,000 man-made structures. Unfortunately, the Camp Fire’s destruction isn’t limited to the destruction inflicted by its flames. This mass burning of a variety of natural and man-made sources has resulted in smoke containing a myriad of small particles that can be hazardous when inhaled. Thus, the smoke produced from the Camp Fire, which is spreading over 150 miles away from the fire and polluting the air of California, is a matter of great health importance.

Rim Fire Yosemite National Forest 2013

The link between adverse health effects due to smoke produced from forest fires and those due to emissions produced from other sources such as diesel engines and industrial factories has long been established. Specifically, exposure to these air pollutants is linked with the onset of respiratory effects such as bronchitis, increased asthma attacks, elevated blood pressure, atherosclerosis, and, for more susceptible individuals, heart attack or stroke.

Alveolar sac lined with capillary bed. Anatomical view of Air Blood Barrier (ABB).

These adverse health effects are largely driven from the small, ~1µm – 10µm in diameter, solid and liquid particles (PM) contained in smoke or emitted from a specific source. Due to these particle’s small size, they are able to travel throughout the lung after inhalation and negatively affect both the conducting and gas exchange regions of the lung. Once the particles have “landed” in a region of the lung, they can persist for days and begin to elicit a pro-inflammatory and oxidative stress response which can exacerbate asthma symptoms and damage integral components of the lung, leading to various respiratory effects.How these particles cause adverse cardiovascular effects is an active area of research. There are three proposed mechanisms: 1) particles smaller than 2.5µm in diameter travel through the lung, pass the alveolar blood barrier (ABB), and enter the bloodstream leading to direct vascular damage, 2) particles that reach the ABB, but do not pass, can induce oxidative stress in the underlying vasculature indirectly, and 3) particles can interfere with the autonomic and central nervous system leading to irregular signaling and irregular heart rate.

Overall, while some of the mechanisms leading to the variety of adverse health effects induced by PM exposure are still unknown, it is clear that PM exposure can be detrimental. When forest fires are near it is extremely important to listen to the local official’s recommendations for staying safe – even if the flames are 100+ miles away! Thus, as the incidence of forest fires continues to rise, likely due to factors such as climate change, we need to be mindful of both the destruction the flames create and the hazardous air the fires can produce.

Peer Edited by Rita Meganck and Jacob Pawlik.

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Time to quit “Ordinary Smoking”

For thousands of years, the tobacco plant has been used for various purposes, ranging from general enjoyment to medicinal uses. Apart from the sniffing and chewing of tobacco, the more common means of tobacco use today is smoking. Nicotine, the drug in question, can have positive psychiatric effects, but is also very addictive thus leading to dependence and other severe health effects. Although the harmful effects of tobacco have been known for decades, nicotine addiction continues to be one of the major causes of noncommunicable diseases and mortality worldwide.

Despite the availability of therapeutic alternatives, nicotine’s inherently addictive nature makes smoking cessation a real challenge for users.Traditionally, combustible products have ruled the tobacco market where smoke from the burning of tobacco delivers nicotine to the users, along with thousands of toxic and carcinogenic compounds. These products mainly include cigarettes, little cigars, cigarillos, cigars and hookah. In addition, flavors are added to mask the harsh taste of tobacco and facilitate new user recruitment. There was also an attempt to manufacture safer cigarettes, known as light cigarettes which ultimately failed to deliver the promise of reduced harm. Products with lower nicotine content have also been adopted to reduce the extent of addiction. Overall, the central effort has continued to develop products that deliver nicotine efficiently without the toxic compound load.

Tobacco products have evolved significantly over the decades

Tobacco products have evolved significantly over the decades

In this quest, e-cigarettes were introduced in the mid-2000s which have gained rapid popularity among existing and naive users. Simply speaking, these products are composed of nicotine in an organic solvent that creates a nice visible cloud of vapor. Enticing flavors and attractive packaging were used to attract users. Originally conceptualized as an aid for smoking cessation, e-cigarettes quickly became a topic of debate dividing health professionals and regulatory authorities. On one hand, vaping does result in reduced harmful compound exposure, but it is suspected to act as a “gateway” to nicotine addiction in youths due to tempting flavors. Additionally, there is grave concern about the long-term hazardous health effects unique to inhaling the e-liquid and flavor compounds. Currently, thousands of different flavored e-liquids are available in the market and the severity of use was even acknowledged by Oxford dictionary by making “vape” the word of the year in 2014. The Internet is also full of vaping videos also called “cloud chasing”. However, e-cigarettes do not to provide a satisfactory nicotine “kick” to the users and also pose danger to the users.

So, what’s next? The next big thing for the US tobacco market is the heat-not-burn products; strategically named “iQOS”, or I Quit Ordinary Smoking. The principle is based on heating instead of burning the tobacco to provide the nicotine with reduced toxic chemical compound generation. Already launched in different parts of the world, iQOS, also known as “heat sticks”, promise nicotine delivery with reduced harmful compound exposure. Research from the tobacco industry supports these ideas. Currently, iQOS is under review in the US by FDA, and if approved, have the potential to completely replace combustible tobacco, as we know it. However, with addition of flavors and selective marketing strategy, these may well be the next biggest concern for health professionals.

Acknowledgements: Drs. Robert Tarran and Boris Reidel for their support.

Edited by Nicole Smiddy

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