Sanitizing lights in school buses

[FL420]

Denver (CO) Public Schools buses to get virus and bacteria-killing ceiling lights.
https://denver.cbslocal.com/2020/11/...0and%20faculty.

[Yosemite77]

These lights are effective against bacteria, mold, and fungi. Unfortunately, they are not effective against viruses, and in particular, not the SARS CoV-2 virus.
It seems to me the Denver schools could have put this money to better use.

[jergle]

A ridiculous waste of tax dollars. Even the viosafe light company says the lights are effective for "bacteria, mold, and fungi", NOT viruses. It wouldn't surprise me if there are some kickbacks going on, but really, do the people that come up with these things not know how to use Google?

[Solo_RV_Guy]

Obviously there is some kind of sell job at work. None of the "visible" spectrum UV is virucidal. UV-C - around 270nm wavelength - is virucidal. It can disable anthrax spores (stubborn things, those are), the exposure time/level for which is the standard currently in use for UV-C sanitizing of high-touch equipment used in broadcasting and event production (think- commentator mics/headsets and their control panels, walkie talkies used by crew, wireless microphones, intercom packs and headsets, etc). The UV irradiation is done after bulk-removal cleaning as UV-C can't penetrate through gunk, grime, and... uh... mucous.

UV-C is not for use where humans or animals can be exposed to it and commercial units have motion detectors to shut off the unit if someone gets too close.

I'm with the folks that find this to be an inappropriate use of the technology if the purpose is to reduce transmission of SARS-CoV-2. Maybe Denver school buses have a mold problem nobody is talking about?

Pre-edit PS (tl/dr): UV-C is useful for air sanitizing in closed systems, and some broadcast trucks have added these systems. Engineering and switching trucks generate a lot of internal heat and the HVAC was designed to minimize outside air exchange; the use of UV-C can substantially mitigate the risk of using recirculated air, the primary infection vector. There are very few *substantiated* cases of fomite ("fomite" means an infectious agent on a surface that is mechanically introduced into a host) transmission of SARS-CoV-2. Note the word "substantiated", it's used because under the circumstances of an individual's infection, respiratory transmission was far more likely. The likelihood of having infectious levels of active virus on a surface increases proportionately to the number of persons that sneeze, cough, or touch surfaces after doing so. This is why self-serve buffets are not a good idea - everyone uses the same serving utensils, often without hand washing between service and before eating... So in high use, high touch areas the cleaning and sanitizing of surfaces becomes more important, especially if the persons involved are "high value" like athletes, entertainers, musicians, or corporate CEOs.

[Kraken]

Their heart is in the right place, but essentially pointless when kids crowd in a bus. It spreads by air far more than touch.

[Ray,IN]

I agree with solo rv guy. IMO this is what that school corporation should be using during this SARS-CoV-2 pandemic.

https://www.genengnews.com/topics/tr...a-and-viruses/
Even that has limitations, dirty surfaces reduce effectiveness of Far UV light. Around my area many doctors and hospitals are using this to reduce the amount of virus in the workplace.


This is very interesting reading if you wish to take the time: https://www.researchgate.net/publica...Susceptibility

[FL420]

I apparently am guilty of not vetting my source before posting the OP. Since both the written article and the news clip made references to the COVID-19 pandemic and "germs" instead of "viruses" and only one reference to "bacteria" I mistakenly assumed the lights would kill viruses. I was wrong. I already knew that viruses required UV light to kill them.
I got to know Albert Samora, the Executive Director of the DPS Transportation Services, when he was the Maintenance Manager of the Boulder Valley School District(BVSD) Transportation Department. He is a good guy who tries to do the right thing.
I suspect he and the school board are under tremendous pressure to do SOMETHING, ANYTHING to get students back on the buses and into the classrooms ASAP. Almost all the school districts along the Front Range tried online learning as a result of the first wave of the virus. Almost immediately they got pushback from parents who weren't used to being cooped up with their kids 24/7 responsible for their childcare and helping with their education. Teachers, staff and school bus drivers were conflicted. They needed their jobs but were afraid of catching the virus from daily close exposure to possible carriers.
Most of the school districts tried different strategies to shift the students from online learning back to inperson learning in the classrooms after the cases plateaued. Within a few weeks new cases arose in the schools requiring many students and staff to be put in isolation and many more who were exposed were required to self quarantine at home. The present third wave, much worse than the first wave, has caused almost every Front Range school district to shutdown the schools sending everyone back to online learning.
Many people are protesting the shutdowns in front of schools and School District offices. I will not speculate here on how many protestors get their "news" and medical advice from Fox News and how many get it from CNN.
Back to the subject at hand. Almost every bus parking spot in the BVSD bus terminals was provided with a long 120Vac cord which every driver was required to plug into the bus after the last trip of the day if the temps were forecast to drop near or below freezing overnight. Each bus was fitted with an electric block heater or a Webasto engine heater. The infrastructure is probably already in place in many school bus yards in cold winter weather communities to power UV light sources all night in the buses when they are sitting idle and empty.
That's my suggestion for dealing with the virus in school buses.
[emoji40]

[Solo_RV_Guy]

Originally Posted by FL420

I apparently am guilty of not vetting my source before posting the OP. Since both the written article and the news clip made references to the COVID-19 pandemic and "germs" instead of "viruses" and only one reference to "bacteria" I mistakenly assumed the lights would kill viruses. I was wrong. I already knew that viruses required UV light to kill them.
I got to know Albert Samora, the Executive Director of the DPS Transportation Services, when he was the Maintenance Manager of the Boulder Valley School District(BVSD) Transportation Department. He is a good guy who tries to do the right thing.
I suspect he and the school board are under tremendous pressure to do SOMETHING, ANYTHING to get students back on the buses and into the classrooms ASAP. Almost all the school districts along the Front Range tried online learning as a result of the first wave of the virus. Almost immediately they got pushback from parents who weren't used to being cooped up with their kids 24/7 responsible for their childcare and helping with their education. Teachers, staff and school bus drivers were conflicted. They needed their jobs but were afraid of catching the virus from daily close exposure to possible carriers.
Most of the school districts tried different strategies to shift the students from online learning back to inperson learning in the classrooms after the cases plateaued. Within a few weeks new cases arose in the schools requiring many students and staff to be put in isolation and many more who were exposed were required to self quarantine at home. The present third wave, much worse than the first wave, has caused almost every Front Range school district to shutdown the schools sending everyone back to online learning.
Many people are protesting the shutdowns in front of schools and School District offices. I will not speculate here on how many protestors get their "news" and medical advice from Fox News and how many get it from CNN.
Back to the subject at hand. Almost every bus parking spot in the BVSD bus terminals was provided with a long 120Vac cord which every driver was required to plug into the bus after the last trip of the day if the temps were forecast to drop near or below freezing overnight. Each bus was fitted with an electric block heater or a Webasto engine heater. The infrastructure is probably already in place in many school bus yards in cold winter weather communities to power UV light sources all night in the buses when they are sitting idle and empty.
That's my suggestion for dealing with the virus in school buses.
[emoji40]

"All politics is local".

Your post actually has a lot to unpack - and not in a bad way. I think the most telling is that parents are simply not accustomed to (and are ill equipped for) educating their kids in formal subjects. I hope these parents come away with more appreciation for teachers!

If your observation about the local climate desiring students to be on buses, in classrooms, etc is as correct as I think it is, the product under discussion is "sanitation theater" in the same way the TSA is ridiculed for the passenger-facing screening. It's for show (their real work is not done in public view); "A little song, a little dance, a little seltzer down the pants..." In a way it's sad to see this, but parents elect school boards to create and enforce policy and if this make parents feel better (no matter how ineffective the "solution" is), District employees who want to keep their jobs will not push back. The side benefit is that bacteria and mold will be deactivated, but there's nothing anti-viral - and that's the part that makes me sad for the students. Their parents are self-deluding about how they're spending school monies.

The way to make in person learning safer would be masks, distancing, enhanced hand hygiene, and effective air handling with fresh air exchanges (or chemical/UV-C treatment of recirculated air). At home, it's best for families to not socialize with others not from their own households for extended periods of time (>15 minutes, give or take). Avoid crowds, unmasked folks, and persons who scream, shout, or otherwise spew their mucous and respiratory droplets into the air. It would be silly to make schools "safe" but have students bring the infection from home... and that seems to be happening in several jurisdictions.

Distancing is the hardest part of in person education - schools were not built with this in mind. Air exchange is probably next, as HVAC systems in places like schools have tended to be designed for energy efficiency as a primary goal and increasing air exchange will probably cause costs to go up. Ditto if existing air handling promotes spread because of air direction or speeds, or both. Fixes for those problems are not trivial or cheap.

We need to continue our healthy behavioral standards for at least another year, maybe more, until enough of the population is vaccinated. Maybe then we can "Rewind to 2019."

[KanzKran]

So-call far UV-C, which has a wavelength of around 222nm if I remember correctly, is safe for people and animals and breaks down viruses the way 'regular' UV-C does. But it can't penetrate the water layer on eyeballs, or dead skin cells which we're covered in, so it's supposedly safe. It's still under investigation and development (Columbia University I think is leading this), and if it goes mainstream, it would be more effective than what they're putting in those buses. Mainly useful for purifying air in large public spaces, I would think.

Having said that, any radiation is only going to 'clean' what it hits. Stuff in shadows will escape unscathed. Which is why the UV-C machines that roam patient rooms and airplane isles have to roam - to shine UV on as much as possible. And even then, some areas won't get sanitized. But it's better than nothing, I suppose.

Might be better to blast the bus interiors with ozone, though that has its downsides, too.

No easy answer, I'm afraid.

Oh, and while sunlight is great for many things, I don't believe any UV-C from the sun actually gets through the atmosphere.

And of course, since I'm not a biomedical physicist, it's just talk.

[Solo_RV_Guy]

Originally Posted by KanzKran

So-call far UV-C, which has a wavelength of around 222nm if I remember correctly, is safe for people and animals and breaks down viruses the way 'regular' UV-C does. But it can't penetrate the water layer on eyeballs, or dead skin cells which we're covered in, so it's supposedly safe. It's still under investigation and development (Columbia University I think is leading this), and if it goes mainstream, it would be more effective than what they're putting in those buses. Mainly useful for purifying air in large public spaces, I would think.

Having said that, any radiation is only going to 'clean' what it hits. Stuff in shadows will escape unscathed. Which is why the UV-C machines that roam patient rooms and airplane isles have to roam - to shine UV on as much as possible. And even then, some areas won't get sanitized. But it's better than nothing, I suppose.

Might be better to blast the bus interiors with ozone, though that has its downsides, too.

No easy answer, I'm afraid.

Oh, and while sunlight is great for many things, I don't believe any UV-C from the sun actually gets through the atmosphere.

And of course, since I'm not a biomedical physicist, it's just talk.

Exactly correct about UV Dark Shadows. That's why the UV-C robots roam, articulate, and do some fancy tricks. Claims of disinfection requires dosimeter cards or calibrated sensors to verify exposure, and those get expensive for non-medical use.

The most likely use for UV-C is in air handling and at least one manufacturer (Siemens) *claims* they have proof of anti-viral action in HVAC products available 'right now'. For places or situations where sufficient fresh air exchange is not possible, sanitizing the recirculated air and ensuring air flow is ceiling to floor, makes spaces usable. On a school bus? I confess it's been a couple of days/decades since I've been on one. Are they climate controlled, sealed environments? Absent some Jedi mind-trick UV-C robot, the way to disinfect the bus involves common sanitizers like quaternary ammoniums and a cloth; wipe down the high touch surfaces at the beginning and end of each shift/run. The ionizing sprayers used in aircraft are another possibility.

Or we teach the kids to not lick the seat backs, wash their hands/use sanitizer, and wear their masks until they get home. Call me a heretic but don't call me late for supper!

Final thought: there have been a couple of accounts of Chinese port workers or freight handlers contracting coronavirus while working inside shipping containers and air freight pods that came from Europe or the USA. What is not yet clear is if the infection vector was from the air trapped inside, or was transferred from the surfaces of the goods or products to the hands of the workers, who introduced it into their bodies. What is real, and what is counterfeit Memorex, remains to be seen.

[FL420]

Almost all students transported to and from public schools on buses travel on yellow Type C and Type D buses. Type C buses are the typical "long nose" buses with the engine in front of the windshield and the entry/exit door behind the front wheels much like a Type C motorhome. Type D school buses usually have the engine behind the windshield and the entry/exit door behind the front wheels much like a gas or FRED Class A motorhome. They all have a long unobstructed aisle from the front entry/exit stairwell to the rear emergency exit door. The rare exceptions are the large quite rare rear engine diesel or CNG powered pushers. Propane-powered, hybrid electric/diesel and most recently all electric buses are making slow inroads into some fleets.
School buses are designed according to Federal Motor Vehicle Safety Standard(FMVSS) 222 to have very specific seating requirements for occupant protection in a collision or sudden maneuvers. Construction materials, seat back height(24" or 28",) seat back thickness(4",) seat width (39" except for last row before the emergency exit door of 26") and spacing between seats(24".) The design concept is descibed as "compartmentalization" designed to protect occupants in most situations except for T-bone type side collisions and rollovers.
The unobstructed aisles the length of the bus and convenient access through the rear emergency exit door should make it very easy for a mobile robotic UV-C device to illuminate almost aii the surfaces except the bottoms of the seats in a yellow school bus. Even smaller activity buses have a central aisle suitable for a device of this kind.
Most public school buses spend about 12 continuous hours parked in a bus terminal parking lot. Often those bus terminals, especially in more northern latitudes, already have the electrical infrastructure to provide electricity to each bus block heater.
[emoji40]

https://stnonline.com/news/school-bu...2010%20persons.

[Solo_RV_Guy]

Originally Posted by FL420

Almost all students transported to and from public schools on buses travel on yellow Type C and Type D buses. Type C buses are the typical "long nose" buses with the engine in front of the windshield and the entry/exit door behind the front wheels much like a Type C motorhome. Type D school buses usually have the engine behind the windshield and the entry/exit door behind the front wheels much like a gas or FRED Class A motorhome. They all have a long unobstructed aisle from the front entry/exit stairwell to the rear emergency exit door. The rare exceptions are the large quite rare rear engine diesel or CNG powered pushers. Propane-powered, hybrid electric/diesel and most recently all electric buses are making slow inroads into some fleets.
School buses are designed according to Federal Motor Vehicle Safety Standard(FMVSS) 222 to have very specific seating requirements for occupant protection in a collision or sudden maneuvers. Construction materials, seat back height(24" or 28",) seat back thickness(4",) seat width (39" except for last row before the emergency exit door of 26") and spacing between seats(24".) The design concept is descibed as "compartmentalization" designed to protect occupants in most situations except for T-bone type side collisions and rollovers.
The unobstructed aisles the length of the bus and convenient access through the rear emergency exit door should make it very easy for a mobile robotic UV-C device to illuminate almost aii the surfaces except the bottoms of the seats in a yellow school bus. Even smaller activity buses have a central aisle suitable for a device of this kind.
Most public school buses spend about 12 continuous hours parked in a bus terminal parking lot. Often those bus terminals, especially in more northern latitudes, already have the electrical infrastructure to provide electricity to each bus block heater.
[emoji40]

https://stnonline.com/news/school-bu...2010%20persons.

Yepper. My point was that UV-C *can* work. The issue with claiming a sanitizing level of radiation was applied must be proven initially and then in periodic performance audits.

I think the uniform nature of school bus seating would allow programmable or purpose-built sanitizing robots, but... it would take anywhere from a few minutes to maybe a hour to disinfect a bus, then the robot would need to be moved to another bus.

Generally I like high tech solutions to problems but in the case of sanitizing high touch surfaces in a bus, common disinfectants will work, not require capital equipment expenditures, and sanitizing in this manner is well documented.

And fomite transmission is not extensively documented (and why I brought up the Chinese freight handlers). Most of the cases of fomite transmission are more readily explained by airborne transmission... I'm still casually looking for documented cases of fomite transmission but most of what I'm finding seem to be largely speculative. Not that it cannot or does not happen; I'm pretty sure it can and does, but we don't really have a lot of evidence that points to fomites as a significant infection vector with the SARS-CoV-2 virus... so far.

The bigger problem with school buses are the proximity of the kids, that they are not going to sit there quietly (expelling and inhaling respiratory droplets), and that they're in the bus for longer than recommended durations. Sanitizing the bus interiors is about the lowest payback action that can be taken, in terms of infection control.

[FL420]

"Generally I like high tech solutions to problems but in the case of sanitizing high touch surfaces in a bus, common disinfectants will work, not require capital equipment expenditures, and sanitizing in this manner is well documented."
"Sanitizing the bus interiors is about the lowest payback action that can be taken, in terms of infection control."
Manually sanitizing every touchable surface on 12 or 13 rows of seats on one bus is very labor intensive and time consuming. The school district I worked for had more than 200 buses spread over 3 terminals located miles apart.
If you ever watched TV news clips showing workers spraying and wiping down surfaces you probably noticed what a sloppy job they did even knowing they were being recorded. In the small rural community where we are hunkered down there is one Walmart and one Safeway. The next closest grocery is 18 miles away. I do all the shopping at WM once a week. This is definitely a "red" county and at least a third of the residents won't wear masks.
After seeing how the WM employees "sanitize" the shopping carts before every use I put a brand new handkerchief in a Ziplock sandwich bag, soaked it in rubbing alcohol and wipe down the shopping cart handles myself. The first time I did it I was unpleasantly surprised to see how dirty the handkerchief became. After 2 or 3 uses it was disgustingly filthy. I replaced it with another new one. The same thing happened to it. They are so filthy that Simple Green, Tide and bleach will not get them clean.
Human nature being what it is I doubt the school bus seats will be any more bacteria and virus free than the WM shopping cart handles. A complete cleaning of a bus interior is an all day job.
If you hire someone as a bus driver, require them to obtain a Class B CDL without an air brake restriction but with passenger and student endorsements then tell them they have to hand sanitize a bus every day you won't have any bus drivers after a short while.
[emoji40]

[Solo_RV_Guy]

Originally Posted by FL420

"Generally I like high tech solutions to problems but in the case of sanitizing high touch surfaces in a bus, common disinfectants will work, not require capital equipment expenditures, and sanitizing in this manner is well documented."
"Sanitizing the bus interiors is about the lowest payback action that can be taken, in terms of infection control."
Manually sanitizing every touchable surface on 12 or 13 rows of seats on one bus is very labor intensive and time consuming. The school district I worked for had more than 200 buses spread over 3 terminals located miles apart.
If you ever watched TV news clips showing workers spraying and wiping down surfaces you probably noticed what a sloppy job they did even knowing they were being recorded. In the small rural community where we are hunkered down there is one Walmart and one Safeway. The next closest grocery is 18 miles away. I do all the shopping at WM once a week. This is definitely a "red" county and at least a third of the residents won't wear masks.
After seeing how the WM employees "sanitize" the shopping carts before every use I put a brand new handkerchief in a Ziplock sandwich bag, soaked it in rubbing alcohol and wipe down the shopping cart handles myself. The first time I did it I was unpleasantly surprised to see how dirty the handkerchief became. After 2 or 3 uses it was disgustingly filthy. I replaced it with another new one. The same thing happened to it. They are so filthy that Simple Green, Tide and bleach will not get them clean.
Human nature being what it is I doubt the school bus seats will be any more bacteria and virus free than the WM shopping cart handles. A complete cleaning of a bus interior is an all day job.
If you hire someone as a bus driver, require them to obtain a Class B CDL without an air brake restriction but with passenger and student endorsements then tell them they have to hand sanitize a bus every day you won't have any bus drivers after a short while.
[emoji40]

I'm not fundamentally disagreeing, but UV-C presents its own issues: any emitter that can cover the seat backs (both sides), seat cushions, and all touchable surfaces, will probably not be a candidate for permanent installation in a school bus. If a 'robot' is developed, it will require moving from bus to bus as each is sanitized. And it will take anywhere from 10-60 minutes per bus. Personnel will not be able to be in bus or possibly even in the area the sanitizing is taking place.

Also, UV-C does not penetrate much of anything (most glass and plastics, for example, will filter out UV-C even if the glass/plastic is clear), especially grime and other bulk contamination. We found this in cleaning high touch items and microphones used by announcers. You can't convince Mr. McMahon that the microphone grille is sanitary when there is still a lung cookie on it from the last show... no matter how much you zapped it with UV-C. Your experience with wiping down carts at WallyWorld demonstrates this - it if doesn't look clean, how does one know? Removal of soil and bulk contaminants will be needed before UV-C *sanitizing* can take place. This puts us back into the quaternary ammoniums, phenyl phenols, and 70% isopropyl alcohols... if the surface has to be cleaned of bulk contaminates, you might as well use a sanitizer and be done with it.

The efficacy of sanitizing is determined by the Four Cs: chemical, concentration, contact time, and coverage. Liquids will penetrate cracks, break down bulk contamination, and have known actions: we can test for concentration and evaluate wet contact times. It doesn't have to be 'car wash pretty', the surfaces just need to stay wet with sanitizer for the prescribed amount of time.

My final thought: if the disinfectant isn't on the EPA List "N", using it for surface contamination is probably a feel good measure.

Additional thought: with 30 seconds of wet time, 70% isopropyl alcohol, Clorox Disinfecting Wipes, and a particular Lysol wipe (exact name escapes me) will disable the SARS-CoV-2 virus. The CDW and Lysol products have a higher concentration of quaternary ammoniums and hence a shorter contact time.

I think there are applications for UV-C in a viral world, but under current conditions and with equipment currently available, it's not a panacea for school bus disinfection.