1 00:00:02,040 --> 00:00:07,520 Speaker 1: Welcome to brain Stuff from how Stuff Works, Hey, brain Stuff, 2 00:00:07,560 --> 00:00:10,639 Speaker 1: Lauren Vogel bomb here Ah, the sounds of autumn, the 3 00:00:10,720 --> 00:00:13,840 Speaker 1: satisfying crunch of a crisp apple or fallen leaves under 4 00:00:13,880 --> 00:00:17,279 Speaker 1: your feet, or the teeth grinding noise of a leaf 5 00:00:17,280 --> 00:00:21,279 Speaker 1: blower powered by electric or gasoline motors that propel air 6 00:00:21,360 --> 00:00:23,680 Speaker 1: out of a nozzle to send leaves and grass cuttings. 7 00:00:23,680 --> 00:00:27,360 Speaker 1: Flying leaf blowers are probably the most villainized devices in 8 00:00:27,400 --> 00:00:30,080 Speaker 1: the lawn care universe due to the noise that they admit. 9 00:00:30,680 --> 00:00:33,440 Speaker 1: In the mid nineteen seventies, when leaf blowers became ubiquitous 10 00:00:33,440 --> 00:00:36,680 Speaker 1: in the United States, to California, cities adopted early bands 11 00:00:36,720 --> 00:00:39,520 Speaker 1: of the equipment, Caramel by the Sea and Beverly Hills 12 00:00:39,640 --> 00:00:42,879 Speaker 1: labeled the leaf blowers a noise nuisance and banned their use, 13 00:00:42,960 --> 00:00:45,000 Speaker 1: a move that has been followed by hundreds of other 14 00:00:45,040 --> 00:00:48,199 Speaker 1: cities across the United States to some degree. But what 15 00:00:48,360 --> 00:00:50,360 Speaker 1: is it about leaf blowers that people hate? Is it 16 00:00:50,440 --> 00:00:54,320 Speaker 1: the decibels the constancy? The leaf blowers pose real dangers 17 00:00:54,360 --> 00:00:56,480 Speaker 1: to the health of users or others who happened to 18 00:00:56,520 --> 00:00:59,960 Speaker 1: be within earshot. Increasingly, the answer appears to be yes 19 00:01:00,280 --> 00:01:03,600 Speaker 1: to all of the above. Leaflowers may send leaves and 20 00:01:03,680 --> 00:01:06,240 Speaker 1: long clippings for a ride, but the gusts, which reach 21 00:01:06,280 --> 00:01:08,360 Speaker 1: a hundred and eighty to two hundred and eighty miles 22 00:01:08,360 --> 00:01:11,440 Speaker 1: per hour that's about two hundred nine four hundred and 23 00:01:11,440 --> 00:01:15,760 Speaker 1: fifty kilometers per hour, also create a nose clogging swirl 24 00:01:15,800 --> 00:01:20,040 Speaker 1: of fungi, spores, herbicides, and microbes. The resulting dust is 25 00:01:20,080 --> 00:01:23,360 Speaker 1: so aggravating to people with allergies asthma, bronchitis, and other 26 00:01:23,400 --> 00:01:27,080 Speaker 1: respiratory maladies that the American Lung Association recommends staying away 27 00:01:27,080 --> 00:01:30,120 Speaker 1: from leaf flowers altogether. And then there's the air pollution 28 00:01:30,520 --> 00:01:33,440 Speaker 1: operating a commercial leaf blower for one hour, and it's 29 00:01:33,480 --> 00:01:36,000 Speaker 1: as much smog forming pollution as you would if you 30 00:01:36,040 --> 00:01:40,440 Speaker 1: drove a recent midsize car, as say Toyota camera from 31 00:01:40,520 --> 00:01:43,280 Speaker 1: Los Angeles to Denver, which is about a one thousand, 32 00:01:43,280 --> 00:01:47,520 Speaker 1: one hundred mile or one tho hundred kilometer trip. That's 33 00:01:47,560 --> 00:01:51,160 Speaker 1: because most leaf blowers use two cycle engines. They're lightweight 34 00:01:51,200 --> 00:01:54,280 Speaker 1: and inexpensive, but they require a mixture of gasoline and 35 00:01:54,360 --> 00:01:57,480 Speaker 1: oil to run. Unlike more complex engines, they don't have 36 00:01:57,520 --> 00:02:01,320 Speaker 1: separate chambers for fueling lubricants. When operated, the engine wastes 37 00:02:01,320 --> 00:02:05,400 Speaker 1: approximately one third of the combined mixture, releasing carbon monoxide, 38 00:02:05,520 --> 00:02:09,280 Speaker 1: nitrous oxide, and hydrocarbons into the air. These three toxins 39 00:02:09,280 --> 00:02:11,320 Speaker 1: are some of the main culprits and the air pollution 40 00:02:11,360 --> 00:02:14,959 Speaker 1: from leaf blowers. Carbon Monoxide helps form smog. Nitrous oxide 41 00:02:15,040 --> 00:02:16,840 Speaker 1: is a prime ingredient in acid rain and has been 42 00:02:16,919 --> 00:02:21,000 Speaker 1: linked to global warming. Hydrocarbons are cancer causing organic compounds 43 00:02:21,040 --> 00:02:25,800 Speaker 1: that also contribute to smog formation. Plus, leaf blowers are noisy. 44 00:02:26,280 --> 00:02:29,600 Speaker 1: How noisy are they When you engage in conversation, that's 45 00:02:29,600 --> 00:02:32,160 Speaker 1: a noise level of about sixty deciples, according to the 46 00:02:32,240 --> 00:02:35,120 Speaker 1: Center for Hearing and Communication. If you're strolling on a 47 00:02:35,120 --> 00:02:37,880 Speaker 1: sidewalk and a car goes by, that's about seventy deciples. 48 00:02:38,200 --> 00:02:41,000 Speaker 1: A leaf blower, even at fifty ft or fifteen meters away, 49 00:02:41,280 --> 00:02:43,960 Speaker 1: can be up to seventy five deciples, and right up 50 00:02:44,000 --> 00:02:46,840 Speaker 1: close that jumps well into the nineties. According to the 51 00:02:46,840 --> 00:02:50,360 Speaker 1: World Health Organization, any noise above seventy five decibles risks 52 00:02:50,400 --> 00:02:54,600 Speaker 1: causing physical hearing damage. And then there's the mental toll. 53 00:02:54,960 --> 00:02:57,919 Speaker 1: Ms Aphonia is a relatively newly classified condition in which 54 00:02:57,960 --> 00:03:01,600 Speaker 1: people are angered by particular sounds like chewing or knuckle cracking. 55 00:03:01,880 --> 00:03:05,240 Speaker 1: Although leaf blowers aren't mentioned in the diagnosis parameters, it 56 00:03:05,320 --> 00:03:08,240 Speaker 1: stands to reason that missophonia may be related to people's 57 00:03:08,240 --> 00:03:11,160 Speaker 1: dislike of the machines because they're extra sensitive to sound. 58 00:03:11,720 --> 00:03:14,480 Speaker 1: Preliminary data shows that miss aphones brains may have a 59 00:03:14,560 --> 00:03:18,240 Speaker 1: hypersensitive connection between the auditory system and the limbic system, 60 00:03:18,280 --> 00:03:20,200 Speaker 1: which is the part of the brain that's responsible for 61 00:03:20,240 --> 00:03:22,639 Speaker 1: creating emotions. It's so much a part of life or 62 00:03:22,680 --> 00:03:25,160 Speaker 1: misophones that they can be shocked when others don't feel 63 00:03:25,240 --> 00:03:28,240 Speaker 1: or react the same way to certain noises. But being 64 00:03:28,280 --> 00:03:32,280 Speaker 1: irritated by leaf blowers doesn't necessarily mean you're asaphone. Erica Walker, 65 00:03:32,360 --> 00:03:35,880 Speaker 1: a doctoral student at Harvard University's chance School of Public Health, 66 00:03:36,200 --> 00:03:38,960 Speaker 1: discovered that it is far less irritating to create a 67 00:03:39,000 --> 00:03:42,000 Speaker 1: sound than it is to hear it. In a survey 68 00:03:42,040 --> 00:03:44,440 Speaker 1: of one thousand fifty residents and more than a dozen 69 00:03:44,440 --> 00:03:47,800 Speaker 1: Boston neighborhoods, Walker found that the majority of respondents said 70 00:03:47,840 --> 00:03:51,080 Speaker 1: they couldn't control or get away from noises like leaf blowers, 71 00:03:51,400 --> 00:03:53,200 Speaker 1: and they believed that no one really cared that it 72 00:03:53,240 --> 00:03:56,680 Speaker 1: annoyed them. What's more, other research has shown that leafblowers 73 00:03:56,680 --> 00:03:59,920 Speaker 1: emit a low frequency noise that penetrates through outer wall 74 00:04:00,160 --> 00:04:02,280 Speaker 1: into homes and businesses in a way that some other 75 00:04:02,320 --> 00:04:06,920 Speaker 1: noises passing vehicles, for example, do not. However, leaf blowers 76 00:04:06,960 --> 00:04:09,760 Speaker 1: have become an integral part of commercial lawn care. While 77 00:04:09,760 --> 00:04:12,320 Speaker 1: a leaf blower may sound like fingernails across chalkboard to you, 78 00:04:12,440 --> 00:04:14,200 Speaker 1: for the businesses that rely on them for a portion 79 00:04:14,240 --> 00:04:22,440 Speaker 1: of their livelihood, it's probably music to the ears. Today's 80 00:04:22,440 --> 00:04:24,760 Speaker 1: episode was written by Laurie L. Dove and produced by 81 00:04:24,760 --> 00:04:27,080 Speaker 1: Tristan McNeil. For more on this and tons of other 82 00:04:27,080 --> 00:04:42,080 Speaker 1: sensory topics, visit our home planet, how stuff Works dot com.