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Nei Jing Now!
31 minutes | Apr 20, 2020
Your Lungs Matter-24/7 including 4/20
Creator:Jose Luis Calvo Martin & Jose Enrique Garcia-Mauriño Muzquiz; Credit:Getty Images/iStockphoto Your lungs matter. Air matters. Exposures matter. Whatever is in the air that makes contact with your lung tissue matters, whether that’s SARS-CoV-2, coal dust, silica, asbestos, diesel exhaust, wood smoke, tobacco smoke, or cannabis smoke. Lung tissue is delicately designed for the exchange of oxygen and carbon dioxide which takes place across tissue that is one cell wide, approximately 0.2 to 2.5 µm. That’s micrometers, not millimeters. One thousand micrometers in one millimeter. The dainty latticework of the lung tissue would blush the cheeks of veteran patrons of Victoria’s Secret. It is fragile and needs to be handled with care. Lungs are the topic of the day. The entire planet is in a frenzy to protect this vital organ, because breathing is essential to life. We are worried we don’t have enough ventilators to rescue lives. Masks are being mandated to prevent us from getting to that stage. We have essentially all but shut down the global economy. At least 2 billion people on the planet are under shelter in place orders, which has even decreased the shakiness of the planet. Yet, all cannabis dispensaries are not closed for business during the Covid19 pandemic as guidance varies from state to state. Popular perception may be that smoking cannabis is less toxic than smoking tobacco. However, according to Dr. Suzaynn Schick, research reveals “cannabis smoke is chemically similar to cigarette smoke.” Dr. Suzaynn Schick is an Associate Professor of Medicine at the University of California San Francisco. She studies the health effects of air pollution in human subjects, with a special focus on the chemistry and toxicity of smoke and the heart and lung disease caused by smoking and using electronic cigarettes. Her analysis of tobacco industry research showed that the primary constituent of secondhand sidestream cigarette smoke is more toxic than the smoke inhaled by smokers. She also found that the toxicity of secondhand smoke worsens as it ages, creating third hand exposure. By Lokal_Profil, CC BY-SA 2.5, I spoke with Dr. Schick in April of 2019 to learn about her research examining the nature of secondhand smoke generated by cannabis smoke. She is one of the first researchers studying the air pollution generated by cannabis smoke. The chemical content of the smoke generated by smoking tobacco and cannabis is very similar, and just as toxic. This is an emerging area of concern since the legalization of recreational cannabis use in many states in the USA. https://www.epa.gov/air-trends/particulate-matter-pm25-trends Cannabis dispensaries with onsite consumption permits for use by vaping and dabbing can have particulate matter concentrations around 100 micrograms per cubic meter (µg/m3). In those venues where combustion is permitted, which means lighting up and smoking it, the particulate matter concentration can range from 1000 µg/m3 to even higher than what the meters can read. For comparison, the average concentration in outside air across the USA is around 10-12 µg/m3 and has been steadily falling over the last couple decades. Levels in the most polluted cities in the world, like Delhi, Beijing, and Mexico City can range from 100 to 500 µg/m3. The World Health Organization air quality guidelines suggest a limit of up to 10 µg/m3 of fine particulate matter for outdoor air. This is especially concerning for the people who work there and are exposed to these levels for 8-12 hours of the day, as well as for people with pre-existing heart and lung diseases. Even air filters and ventilation systems are not able to bring the particulate matter concentration to an acceptable level. The Federal Drug Enforcement Agency has a complex protocol for conducting research related to cannabis, which makes studying the health effects of cannabis use cumbersome and nearly impossible. The potency of cannabis products is also highly variable, in contrast to the relatively standardized packaging of tobacco products. The legalization of recreational cannabis use isn’t based on solid scientific evidence that it is safe to use in that way. Rather, evidence has been accumulating over the past couple decades of the harmful effects, particularly for young people and those with underlying psychiatric vulnerabilities. This is important to consider given that the 2013 Medical Expenditure Panel Survey (MEPS) showed that 1 out of every 6 Americans is using a psychiatric medication. A statistical brief published by the MEPS in 2018 indicated that about 1 out every 8 children between the ages of 13–17 years had a diagnosis of Attention Deficit Hyperactivity Disorder between 2008 and 2015. The medical use of marijuana probably carries a risk-benefit ratio similar to other medications commonly prescribed and monitored by clinicians. Recreational use has a different use-risk-safety profile than medical use. Dr. Schick also points out the cannabis industry can generate significant tax revenues for governmental entities, more so as the processes get increasingly capitalized and industrialized. Due to federal restrictions on banks supporting the industry, there has been less incentive for large corporations to participate in the cannabis market. In September of 2019, the United States House of Representatives passed the Secure And Fair Enforcement (SAFE) Banking Act which would allow banks to service cannabis companies in states where it has been legalized. At the time of the interview Dr. Schick was preparing to once again study the air pollution at the Hippie Hill 420 Festival in Golden Gate Park. However, this year the gathering has been canceled due to Covid19 shelter in place orders issued by the State of California, which are in effect until further notice. In this interview, Dr. Schick gives a brief overview of the differences between vaping, dabbing, smoking, and edibles, and their varying pharmacodynamics, metabolism, and toxicities. She reports measuring significant levels of aldehydes and ketones in the smoke produced by smoking cannabis, similar to the levels in tobacco smoke. We don’t yet know the identity or levels of noxious gases that are emitted by dabbing or vaping marijuana. NNK chemical structure The studies on third hand toxicities produced by marijuana smoking are also still pending. Third hand exposure refers to the chemicals that sticks to the clothes, furniture, and walls in the rooms where smoking has occurred. The substances can react with ozone to produce a highly toxic substance. In the case of cigarette smoking, nicotine in reaction with ozone produces nicotine-derived nitrosamine ketone (NNK), a potent carcinogen. The Centers for Disease Control and Prevention reports that NNK has been found in the urine of more than a third of nonsmoking adults, with levels 2-3 times higher in children with second and third hand exposure. From her professional scientific perspective, Dr. Schick offers a strong warning that smoking cannabis or tobacco is not safe. She says it is “magical thinking” to imagine there is no health risk from smoking marijuana. And yet, in this era, when we are prioritizing the health and safety of our community by severely restricting our personal freedoms, in order to prevent the lung failure and potential deaths of our fellow citizens, the recreational use of cannabis has been determined to be an essential service.
9 minutes | May 30, 2019
Bicycling is in the Air
It’s still National Bike Month in the USA for a few more days, while the whole summer stretches before us to enjoy our bicycles. In the beginning of every May, Bicycle to Work Day encourages people in the USA to get out of their cars and on to their bicycles, followed by World Bicycle Day on June 3rd. So bicycles are in the air, so to speak, and more importantly on the ground in motion. According to the US Census data on bicycle ridership, over 800,000 people rode their bicycles to work in 2017, up from 665,000 in 2007. Dr. Satyalaxmi, Director of the National Institute of Naturopathy in Pune, India recently resumed bicycling after a gap of 35 years. She is now commuting to her office daily, hoping to inspire others to do the same. In this short interview she shares the slight hesitations she had about getting back on her bicycle after so many years. as well as how she is enjoying bicycling and her increased level of fitness and agility. She notes that mainstream society associates social status with mode of transportation, with bicycles being thought of as transportation for people who can’t afford cars. However, she loves the sense of freedom she feels on her bicycle, and the independence from having to coordinate with her chauffeur, which is a problem many or most of us don’t have. Naturopathy promotes the deployment of non-pharmaceutical modalities for prevention and treatment of injuries and illnesses. As such, active transportation is aligned with the theory and practice of naturopathy. Even the American Public Health Association endorses active transportation, which includes bicycling, walking, skateboarding, kick scootering, roller skating, skiing, snoeshoing, even wheelchairing, as an essential part of creating a healthy lifestyle, community, and environment. Pune was historically known as the “Cycle City of India”. In my recent stays in Pune I mostly noted the intense traffic congestion and concomitant air and noise pollution. I used a kick scooter to move about town, much to the delight of onlookers who have likely never seen a female in my age category on a kick scooter. I also met bicycle activists and learned of the efforts to promote bicycling and make it safer and more pleasant. There’s a bicycling revival underfoot, so to speak. The Pune Municipal Corporation is collecting data and has laid out a Bicycle Plan. Bicycle sharing schemes similar to ones popular in Europe and the USA are now coming to India too. Making active transportation a mass transit reality across the globe will require infrastructure that keeps bicycles safe from larger motorized vehicles, affordable housing so everyone can reside close to where they work and live, and a cultural shift that affords health and mobility a greater social status than luxury fossil fueled vehicles, self or chauffeur-driven. The end of May is not the end of bicycling. I encourage you all to join the National Bike Challenge, which encourages creating community, camaraderie, and casual competition around bicycling and runs all the way through September. I wish you all a happy and safe summer and autumn of bicycling. Please share your bicycling stories here or on the Ready, Steady, Go! action item encouraging your own Pedal Power! #June3WorldBicycleDay #NationalBikeMonth #BikeToWorkDay #BTWD #BikeToWorkWeek #BikeMonth #BikeToWork #BikeCommuting #PedalPower #FeetBeforeWheels
17 minutes | May 9, 2019
Teacher Appreciation: A Reorientation Towards the Heart
Mr. Steve Ollanik on the California Zephyr Amtrak It’s Teacher Appreciation Week in the USA and I’d like to take the opportunity to honor another extraordinary teacher. I met Mr. Steve Ollanik on a train journey from Chicago to Emeryville, California earlier this year. In the dining car one morning, I struck up a conversation with a warm, friendly man wearing an unusual “I <3 Physics” T-shirt which amused me. I soon discovered this jovial man had abandoned life as a successful Silicon Valley computer software engineer working on cutting edge artificial intelligence 22 years ago to become a third grade teacher. To this day he has never looked back. When his wife succumbed to melanoma, Mr. Ollanik re-evaluated his life priorities. He remembered how much he enjoyed being with children. In his pre-engineering days he had led children’s groups at the Jewish Community Center and had been a camp counselor in college. Upon reflecting on what was really important to him, he decided to cut back on his responsibilities as an engineer and started volunteering in a local school as a teacher’s aide. He says the day he set foot in the classroom again he knew he wanted to be a teacher. He moved to Boulder, Colorado to be closer to his family of origin, attended the University of Colorado to prepare to become a teacher, and then started teaching third graders. While most of his peers commend him for his courage to walk away from a lucrative career in engineering to follow his heart, he notices the lack of respect in society for teachers. It comes out as assumptions about his level of intelligence, until he reveals he has a graduate degree in computer science and engineering from MIT. He points out, as we are all well aware, teachers are severely underpaid and unsupported by taxpayers. Yet, Mr. Ollanik doesn’t lament this for what he gains in fulfillment and joy is priceless to him. In this interview you will hear the dedication in his voice to his students, his sense of satisfaction when he sees the light go on in his students’ eyes, knowing he is making a meaningful positive impact in the lives of young people. How much he really cares about his students is obvious in this conversation. Some of his students call him “Dad”, or even “Mom”, which is rather hilarious as he’s a fully bearded fellow. That speaks either to his capacity to nurture his students, or says something about abnormal hair growth in adult females in his locality. He reports he has had a good solid laugh every day of the past 22 years he has been teaching because kids are simply delightful. Teachers all over the country, including California, Colorado, Arizona, West Virginia, Oklahoma, Kentucky, are striking, and winning. Not only for better pay and improved infrastructure, but also to change policies that favor performance-based pay and charter schools. Teachers also support sanctuary protections for undocumented children. (People with personal relationships with each other generally want to protect each other.) Activists in North Carolina included expansion of Medicaid and mental health services in their demands, because students need to be healthy in order to learn. They are taking an approach that is holistic, or even “beyond holistic“. Teachers want and deserve more support from society to do the work we have entrusted them to do on our behalf, that is to educate our children. It isn’t just about salary anymore, it is about the future of public education, and the country. Cartoon courtesy of Gustavo Rodriguez, www.garrinchatoonz.com #TeacherAppreciationWeek #ThankATeacher #PayTeachers #TeachersStrike #SupportTeachers #RedForEd
24 minutes | Dec 24, 2017
Balancing Bipolar with Yoga
Happy Holidays! As we close out 2017, it is worthwhile to explore some tools to support our personal peace of mind in the midst of political insanity. The West has known for a few decades that yoga can be instrumental in managing mood and psychiatric imbalances. In the East it has been self-evident since forever. For this installment in the Stories of Resilience series, I began an interview with Ms. Lizandra Vidal to discuss her recovery from a spinal cord injury she sustained a couple of years ago. In the course of our introductory conversation, before beginning the interview, she shared with me her journey with a diagnosis of bipolar disorder. As her experience and perspective are fascinating and inspiring, I requested permission to share that part of her story of resilience as well. We deferred talking about her recovery from the spinal cord injury until a later date. Cartoon courtesy of Gustavo Rodriguez, www.garrinchatoonz.com The practice of focusing the mind in unison with awareness of the body, otherwise known as yoga asana, as well as meditation, has been instrumental in her capacity to manage her symptoms. Through the self-awareness she has cultivated she is able to catch shifts in her mood early, before they spiral out of control. She then makes the appropriate changes in her life, and seeks help to bring her mind, body, spirit, and life back into balance. I’m delighted to share our edited conversation with you. I welcome your comments, experiences, and responses. Lest you conclude that Ms. Vidal’s experience with yoga, meditation, and her mental functioning is anecdotal, there are some scientific studies that say she’s not alone. A 2013 review of twelve randomized controlled trials on the effect of yoga on depression, published in Depression and Anxiety, the official journal of the Anxiety and Depression Association of America, concluded there’s moderate evidence for positive short-term effects of practicing yoga compared with “usual care”. In another study, a cohort of thirty-three high functioning people, defined as those who score well on the Multidimensional Scale of Independent Functioning, were interviewed individually or in focus groups as part of research published in 2010 in Clinical Psychology and Psychotherapy. The subjects reported successful self-management techniques that fall into five categories: “(1) sleep, diet, rest and exercise; (2) ongoing monitoring; (3) reflective and meditative practices; (4) understanding BD and educating others; (5) connecting to others and (6) enacting a plan.” Cartoon courtesy of Gustavo Rodriguez, www.garrinchatoonz.com A similar study published in 2005 in the Australian and New Zealand Journal of psychiatry, interviewed one hundred people with a diagnosis of bipolar disorder who had “stayed well” for the two years prior. The research concluded that “strategies to stay well” included: “acceptance of diagnosis, mindfulness, education, identify triggers, recognize warning signals, manage sleep and stress, make lifestyle changes, treatment, access support, and stay well plans.” A survey of 109 yoga practitioners with bipolar disorder, published in the Journal of Psychiatric Practice in 2014, reported benefits as well as adverse effects of yoga on their condition. The 86 respondents commonly described less anxiety, improved cognitive effects, such as focus and acceptance, and fewer intrusive thoughts. Many also reported positive physical effects, such as improved fitness, weight loss, and increased energy. Some respondents did experience physical injury or pain. Five subjects felt there were instances in which yoga practice increased their agitation or symptoms of mania. Another five felt yoga practice had at times made them more depressed or lethargic. A 2016 meta-analysis of 17 studies, published in the Journal of Evidence Based Medicine, looked at the effect of yoga on people with anxiety disorder. Not surprisingly, it found the more you practice, the more you benefit. Furthermore, the more anxious you are, the more you benefit. Even as yoga and meditation can be beneficial in managing anxiety and depression, it is not uncommon for some people to lose the balance of their mind in the pursuit of the balance of their mind. Some may refer to that experience as a “spiritual crisis”. It is difficult to define a spiritual crisis, and furthermore to distinguish a spiritual crisis from a psychotic episode. Psychosis occurs when thought and emotions are disordered to the extent that the connection to socially accepted reality is strained, or completely disrupted. In a spiritual crisis, the person also has an extreme disruption in their understanding of their values, beliefs, identity, purpose, goals, and identity. Both psychosis and spiritual crisis can be triggered by an intense emotional experience, often of loss. To an observer, the behavior can appear similar, however the person experiencing a spiritual crisis is introspective, reflective, consciously questioning and examining the paradigm they are operating in. They are actively looking to transform their reality system, whereas someone in a psychotic episode employs much less agency. A psychotic episode is emotionally regressive, and often damaging to occupational functioning and personal relationships. While a spiritual crisis may involve a period of dysfunction, the outcome is generally more progressively transformative. The danger is in confusing the two in the initial stages. Medicating the latter can shut down the positive aspects of the transformation. Both experiences need to be cared for with empathy, compassion, and understanding. The Icarus Project is a support network for people who have been, or could be given a mental health diagnosis. Their vision is to accept the entire range of human experience without the confines of categories, labels, and diagnoses. Stay tuned for more in-depth information on this in a future podcast. There is value in exploring the spectrum of realities, rather than mindlessly ascribing to the commonly accepted perception of what is normal reality. Whether one is having a psychotic episode or a spiritual crisis, from the viewpoint that nothing is broken and nothing is lacking, one can go through either experience with resilience for one’s own well-being. In future conversations, we will explore further how each of us interact and intersect with our collective consciousness. In the meantime, refining your awareness of your breath, body, thoughts, and emotions is the foundation of maintaining physical, mental, emotional, and spiritual harmony. Yoga and meditation are excellent tools. The breath as it enters and exits the nostrils is the lifeline to keep you safe in your practice. Awareness and Equanimity are the two wings of Peace. I wish everyone a peaceful, joyful, healthy, prosperous, harmonious transition into 2018 filled with meaningful time spent with loved ones and new friends. May Peace Prevail in All Our Worlds!
20 minutes | Nov 1, 2017
Diwali: The Festival of Noise OR Honk If You Hate Noise
For years I wanted to celebrate Diwali in India. I wanted to see homes lit up with clay oil lamps and feel the exhilaration of firecrackers. I now hope this is my last Diwali in India, until the cultural habit of firecrackers changes to something less toxic. Firecrackers Just Aren’t All They Are Cracked Up To Be Actually, I have been in India on Diwali before. In 1997, I was on the back of a motorcycle riding from Madhya Pradesh to Haryana, with clay oil lamps in the villages and strings of multi-colored flashing electric bulbs lighting the way. There was a simple, touching beauty to the quiet ride. I arrived in my grandfather’s village the day after Diwali, in time to light a few leftover firecrackers. In 2015, I was in Pune on Diwali and celebrated with my neighbor who had decorated her entire apartment with lights and rangoli, the colored powder artwork people apply on the ground everywhere, inside and outside. The city became festive, the people more friendly. People dressed their finest and behaved their best. It was exactly like Christmas in America. However, the additional noise and air pollution, on top of already high baseline levels, is not a warm invitation to the Goddess of Health, Wealth, and Prosperity by any measure. Tradition has everyone scrupulously cleaning their homes, grooming impeccably, whitewashing their walls, balancing out their accounts, behaving with grace and generosity. Meanwhile, simultaneously, they are spewing excessive noise and toxic pollutants into the atmosphere. If I was the Goddess, I’d turn around at the city gates and go somewhere clean and beautiful. Let’s talk about the noise factor first. It starts a few days prior to Diwali. The first cracker shot is a shock to the system. Bam! It sounds like a bomb just went off, inside the apartment complex. After, you’ve caught your breath, the birds have settled back into their trees and the dogs have stopped barking, another one goes off, disturbing the peace again. And this goes on, with increasing frequency as Diwali approaches. And then, on the day of the new moon, people pull out their stockpiles and the city goes bonkers with the crackers. Just a week out from Diwali another long series of firecrackers went off inside the apartment complex, as if someone lit an entire case of firecrackers all at once. We are 11 days out now and the firecrackers are still going. It’s like living in a war zone, except the unannounced acoustic assaults are being perpetrated by your neighbors instead of your enemies. As it is, city life in India is noisy. The ubiquitous unmuffled auto rickshaws roaring through the streets. The incessant honking of horns, for no obvious reason. Often even on a completely empty road, as if to just remind God of one’s existence, like ringing the temple bell on arrival, but everywhere. The road has become the temple. Standards for noise pollution set different limits based on the zoning of the area, as if your ear drums know of the zoning criteria. In India, the zones are classified as Silence, Residential, Commercial, and Industrial, with daytime limits and night-time limits ranging from 50 to 75 dB(A) Leq*, and 40 to 70 dB(A) Leq* respectively. Pune University is a lush, green area of the city. As with many academic institutions, the real estate is prime, and the environment conducive to concentration, imagination, and other cognitive activities. A visit there feels like a relief from the din of the city. It’s zoned as a “Silence”area. The average ambient noise levels at Pune University, as measured by the Maharashtra Pollution Control Board (MPCB) in 2014, the last year for which a report is available on their website, not unexpectedly exceed the limits set by the Environmental Protection Act (EPA) of 1986. On a Sunday, the day of rest, when things do feel quieter, the noise levels measured were 84 dB(A) Leq in the daytime, and 69.8 dB(A) Leq in the nighttime. On a Monday, they were similar at 84 dB(A) Leq and 70.8 dB(A) Leq, daytime and nighttime respectively. The EPA limits for the “Silent” zone 50 dB(A) Leq in the daytime, and 40 dB(A) Leq at night. I won’t detail the rest of the ambient levels in other zones, since you get the idea. You can read the full report here. It’s difficult to find a quiet place or time in metropolitan India. Clearly, there is concern about noise pollution on and around festival days in India, especially Diwali. The Maharashtra Pollution Control Board publishes an annual report that focuses on the Festival of Noise, I mean Lights. The 2016 report for Pune shows the highest level reaching 92.7 dB(A) Leq. The highest EPA limit anywhere anytime is 75 dB(A) Leq. One thing to remember is the dbA scale is not linear. The subjective perception of sound is different than the actual power of the sound waves, the sound intensity. The human ear perceives an increase of 6-10 dB as a doubling of sound intensity. But the sound pressure on the ear drum is doubled with an increase in just 3 dB. An increase from 60 db to 80 db is 100 times more intense, even though it will only sound like it is four times as loud. The damage to your ears comes from the power of the sound wave, not from how loud it sounds to you. Sound Level Sound Intensity (Power) Perceived Loudness 60 dB 1x 1y 70 dB 10x 2y 80 dB 100x 4y Chart courtesy of Noise Help A firecracker exploding emits 140 dbA of sound power. The maximum allowable unprotected exposure time limit in 24 hours for 140 dBA is ZERO. NONE. NEVER. EVER. For children, the World Health organization sets the zero tolerance time limit at 120 dBA. Meanwhile, in India, it’s most often the children who are setting off the firecrackers. No wonder everyone talks so loudly in India. The MPCB only monitors ambient noise pollution in major metropolitan cities 2 days of every year, and on two major holidays, Ganesha Chaturthi and Diwali. Last year, Miiint Technologies launched a noise monitoring app that gives the power back to the people. The app is rather straightforwardly called the Noise Pollution Monitor. It crowd-sources the data collection from the public and can be used in any country, anywhere, anytime. It’s a free tool by which anyone can get informed about the noise levels their eardrums are being subjected to. On learning about this app, I contacted the developer, Mr. Uday Kothari, CEO of Miiint Solutions. You can listen to my interview with him in the podcast on this post. We discussed the significance of empowering people with collecting data, and the huge increase in the power of the data with a larger sample size. So, download the app and contribute your data points. If you are a statistician and are keen to analyze the data, let us know. You can contact me here. We brainstormed some possible pressure points which could effect a reduction in ambient noise levels. Traffic police and auto rickshaw drivers suffer the ill effects of exposure to long hours of high levels of noise, and air, pollution in India, and ought to have a vested interest in their own health and well-being. At the same time, a driver’s license can easily be obtained without ever passing a meaningful test of knowledge or skill, facilitated by an “understanding relationship”, also known as a bribe. More stringent licensing requirements, enforced by police, could help organize traffic flow so it would be less necessary to honk your horn to inform your fellow roadmates you are coming. Credit: [ UNITED ARTISTS / THE KOBAL COLLECTION ]There was a huge hullabaloo in India when the Supreme Court banned the sales of firecrackers in residential areas to mitigate the noise and air pollution problem around Diwali. People protested their religious freedom was being infringed upon. Fiddlers got on their roofs and cried, “Tradition!” But, firecrackers have only been a part of Diwali celebrations for less than a century. Sri Lanka was conquered with bows and arrows; Rama, Sita, and Laxman were welcomed back to Ayodhya with clay oil lamps, and the Goddess Laxmi prefers clean and quiet. Firecrackers are not traditional, nor are they religious, and they infringe on the fundamental rights of others to a quiet night of sleep. We’ve covered noise here. I suggest covering your ears in India until people decide to drive using their eyes instead of just their ears, install mufflers on auto rickshaws, trust that God sees them, everywhere, worship within their hearts, and celebrate with music and song, instead of pyrotechnic offshoots of ammunition. I just decided I will write this article in three parts, otherwise nobody is going to read it. How’s that for an abrupt ending. Stay tuned for parts 2 and 3, where I’ll cover Diwali air pollution and the occupational health hazards of manufacturing firecrackers. *http://soundpollution.blogspot.in/2005/02/definition-of-dba-leq.html dB(A) is used to denote the dB scale weighted by a scale denoted by A. A in our case is the frequency response of the ear over the audio frequency range(20Hz – 20kHz). “A”, in dB(A) Leq, denotes the frequency weighting in the measurement of noise and corresponds to frequency response characteristics of the human ear. Leq is Equivalent Sound Level. It is a measure of sound level over a period of time. If the sound level of 55 dB for one second is followed by a silence of one second, the Leq will be 52 dB over those two seconds. dB(A) Leq denotes the time weighted average of the level of sound in decibels on scale A which is relatable to human hearing.
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