Tag Archives: damage

Leaf blowers are not only annoying but also bad for you (and the environment)

The seemingly-innocuous leaf blower may actually cause a lot more damage than you’d think — to both your health and the climate.

A groundskeeper blows autumn leaves in the Homewood Cemetery, Pittsburgh.
Image via Wikimedia.

It’s that time of the year: trees are shedding their leaves, and people are blowing them off the pavement. According to the Centers for Disease Control and Prevention (CDC), this quaint image actually hides several health concerns for operators and the public at large.

The inefficient gas engines typically used on leaf blowers generate large amounts of air pollution and particulate matter. The noise they generate can lead to serious hearing problems, including permanent hearing loss, according to the CDC.

Sounds bad

Some noise may not seem like much of an issue, but the dose can make it poison. The CDC explains that using your conventional, commercial (and gas-powered) leaf-blower for two hours has an adverse impact on your hearing. Some emit between 80 and 85 decibels (dB) while in use. Most cheap or mid-range leaf blowers, however, can expose users to up to 112 decibels (a plane taking off generates 105 decibels). At this level, they can cause instant “pain and ear injury,” with “hearing loss possible in less than [2 to] 5 minutes”.

The low-frequency sound they emit fades slowly over long distances or through building walls. Even at 800 meters away, a conventional leaf blower is still over the 55 dB limit considered safe by the World Health Organization, according to one 2017 study. Because they’re so loud, they can be heard “many homes away” from where they are being used, Quartz explains.

This ties into the greater issue of noise pollution. The 2016 Greater Boston Noise Report (link plays audio,) which surveyed 1,050 residents across the Boston area, found that most felt they “could not control noise or get away from it,” with leaf blowers being a major source of noise. Some 79% of responders said they believed no one cared that it bothered them. Leaf blowers are also seeing more use — in some cases becoming a daily occurrence. As homeowners and landscaping crews create an overlap of noise, these devices can be heard for several hours a day.

Image credits S. Hermann & F. Richter / Pixabay.

With over 11 million leaf blowers in the U.S. as of 2018, this adds up to a lot of annoyed people. Most cities don’t have legislation in place that deals with leaf blower noise specifically, and existing noise ordinances are practically unenforceable for these devices. However, there are cities across the U.S. that have some kind of leaf blower noise restrictions in place or going into effect.

Noisy environments can cause both mental and physical health complications, contributing to tinnitus, hypertension, and generating stress (which leads to annoyance and disturbed sleep).

Very polluting

A report published by the California Environmental Protection Agency (CalEPA) in the year 2000 lists several potential hazards regarding air quality when using leaf blowers:

  • Particulate Matter (PM): “Particles of 10 Fm and smaller are inhalable and able to deposit and remain on airway surfaces,” the study explains, while “smaller particles (2.5 Fm or less) are able to penetrate deep into the lungs and move into intercellular spaces.” More on the health impact of PM here.
  • Carbon Monoxide: a gas that binds to the hemoglobin protein in our red blood cells. This prevents the cell from ‘loading’ oxygen or carbon dioxide — essentially preventing respiration.
  • Unburned fuel: toxic compounds from gasoline that leak in the air, either through evaporation or due to incomplete combustion in the engine. Several of these compounds are probable carcinogens and are known irritants for eyes, skin, and the respiratory tract.

To give you an idea of the levels of exposure involved here, the study explains that landscape workers running a leaf blower are exposed to ten times more ultra-fine particles than someone standing next to a busy road.

Additionally, these tools are important sources of smog-forming compounds. It’s not a serious issue right now, but as more people buy and use leaf blowers, lawnmowers, and other small gas-powered engines, these are expected to overtake cars as the leading cause of smog in the United States.

What to do about it

Well, the easiest option is to use a rake — or just leave the leaves where they are, which is healthier for the environment.

But leaf blowers didn’t get to where they are today because people like to rake. Electrical versions, either corded or battery-powered, would address the air quality and virtually all of the noise concerns (albeit in exchange for less power).

While government regulation might help with emission levels, noise concerns might best be dealt with using more social approaches. Establishing neighborhood-wide leaf blowing intervals, or limiting the activity to a single day per week, would help make our lives a little better. As an added benefit, this would also help people feel that their concerns are being heard, and foster a sense of community.

Buy art not cocaine.

Scientists successfully undo cocaine-induced cardiovascular damage in mice

Researchers at the Miller School of Medicine, University of Miami, discovered a potential new pathway to treat the devastating effect of cocaine on the cardiovascular system. They found out that excess levels of reactive oxygen species (ROS), molecules known to be found in the aortas of hypertensive animals and humans, are also involved in cocaine-related cardiovascular disease.

Buy art not cocaine.

Image credits Dave O / Flickr.

ROS are a type of unstable molecules that contain oxygen and rapidly react with other chemical molecules in a cell. An excess of reactive oxygen species inside cells may cause DNA, RNA, and protein damage, and can lead to cell death.

Scientists discovered that cocaine activates the molecule microRNA (miR)-30c-5p, increasing ROS levels in the circulatory system. The team also found that by blocking the activation of miR-30c-5p, they could dramatically reduce damage to the cardiovascular system.

“The biggest surprise to us was that the modulation of a single miRNA-mRNA pathway could have such a profound effect on cardiovascular function,” says Chunming Dong, M.D., study senior author and professor of medicine at the University of Miami.

“This also suggests that targeting this one pathway may have significant therapeutic benefit, which is an exciting possibility.”

The team performed their research using mice. They injected the animals with cocaine and assessed their circulatory health: the mice had high blood pressure, excess levels of ROS, and stiff blood vessels. All these are markers of cardiovascular disease. Researchers also observed a buildup in the miR-30c-5p molecule. When scientists administered cocaine but treated the mice with antioxidants, they managed to inhibit the excessive accumulation of miR-30c-5p and the mice showed no changes in blood pressure, vessel elasticity, or ROS levels.

Doctor Dong says that this is the first study to identify the role of miR-30c-5p in cocaine-related cardiovascular disease. He also notes that the study has some limitations due to the fact that the experiments were only conducted on mice. His research team plans to examine human patients as well, to see if this targeted pathway is viable.

The paper was published in the journal Hypertension, on February 26, 2018.


Neuropathologist examines brains of 111 N.F.L. players, finds 99% had degenerative disease linked to repeated blows to the head


Credit: Pixabay.

It’s no secret NFL players suffer repeated blows to the head and concussions are common. This lifestyle has been previously associated with a heightened risk of developing neurodegenerative diseases but, really, nothing could prepare us for the latest findings of Dr. Ann McKee. The Boston University neuropathologist examined the brains of deceased of 202 deceased football players, which included 111 former professional NFL players. Of these 111 NFL players, 110 had chronic traumatic encephalopathy, known as CTE and thought to be inflicted by repeated blows to the head. Overall, among the 202 brains, 87% showed the diagnostic signs of CTE.

There is no question anymore this is a problem in football

CTE is a degenerative brain disease commonly found in athletes, military veterans, and others with a history of repetitive brain trauma. The disease was formerly believed to exist primarily among boxers and was referred to as dementia pugilistica, which is now classed as a subtype of CTE.

Individuals suffering from CTE will gradually deteriorate their brains and will end up losing brain mass over the years or decades. Some parts of the brains are particularly vulnerable to atrophy while others are prone to become enlarged. Another defining aspect of CTE is the accumulation of tau protein, which serves to stabilize the cellular structure in the neuron but which can damage the function of the neuron when the protein becomes defective.

Clumps of tau proteins are commonly found in the Alzheimer’s diseased brain but what sets CTE apart is that the tau clumps form around small blood vessels, and most often near the bottom of sulci, the deep folds in the brain’s cortex. Severe CTE also affects deeper brain structures like the hippocampus, the amygdala, and the brain stem.

Top: normal healthy brain. Bottom: the brain of Greg Ploetz who played   defensive tackle for the Texas Longhorns and who suffered from severe chronic traumatic encephalopathy. Credit: Boston University Photography.

Top: normal healthy brain. Bottom: the brain of Greg Ploetz who played defensive tackle for the Texas Longhorns and who suffered from severe chronic traumatic encephalopathy. Credit: Boston University Photography.

Mckee and colleagues carefully examined the brains of 202 individuals which were donated by their families to the National Institutes of Health. The men were as young as 23 and as old as 89 when they died, and included a mix of former college football players, NFL players, and a couple of individuals who played football during high school.

The researchers strikingly found signs of CTE in  48 of 53 brains of former college players, seven of eight who played professional football in Canada and nine of 14 semiprofessional players. Astonishingly, 110 of the 111 former NFL players had CTE. Overall, 86 percent of former professional players had severe disease, and 56 percent of college players, the team reports today in The Journal of the American. 

Linemen made the bulk of the individuals studied by McKee’s team. They’re the ones who knock heads the most during a game although they might not be as violently hit as a quarterback. Previously, a team from Stanford found that the average college offensive lineman sustains 62 blows to the head in a single game. Each hit strikes the head with a force equivalent to that of a car crashing into a brick wall at 30 mph.

The symptoms of CTE can be debilitating and may have life-changing effects for both the individual and for his or her family. Common symptoms include memory loss, difficulty controlling impulsive or erratic behavior, impaired judgment, behavioral disturbances including aggression and depression, difficulty with balance, and a gradual onset of dementia.

About 96 percent of the donors whose brains were diagnosed with CTE  experienced progression of their symptoms during life. In fact, this is precisely the reason why the brains were donated by the deceased’s family. It’s very important to keep this in mind given the selection bias. At the same time, CTE can only be diagnosed after death and since the Boston University group started their study, some 1,300 former NFL players have died. Even considering these 1,300 as an undiagnosed nebulous, if we add the confirmed CTE diagnoses, we still end up with a minimum C.T.E. prevalence close to 9 percent, which is vastly higher than in the general population.

Previously, questionnaire-based studies of retired NFL players found depression and memory loss symptoms — both hallmarks of CTE — were presented in 5% to 20% of sampled individuals. This figure might be representative of the CTE prevalence given the present findings.

Whatever’s the case, given the significant prevalence and worrisome symptoms of CTE, much more research is warranted so we can fill in the blanks and, most importantly, devise new ways to protect and treat football players. At the end of the day, football players should be made more aware of the health risks their subjecting themselves.