We have a preponderance of evidence that Covid-19 is spread by aerosols and large droplets expelled through our mouths when we talk and through our mouth and nose when we sneeze or cough. We also have plenty of evidence that (nearly) universal mask-wearing in public is extremely effective in Reducing transmission of SARS-CoV-2. The linked article by Prof. Kim Prather et al is written extremely clearly in plain English and I highly recommend reading it.
I'm embedding two videos because they are helpful to understand social distancing and wearing masks. But, it's important to keep in mind that they are showing hot air instead of droplet and aerosol motion, which does not spread as far.
Schlieren or shadowgraph imagery shows changes of thermal patterns in the air. We expel heated air, which will mix with ambient air and might waft upwards (hot air rises.) Large droplets are heavier and will fall downwards. Aerosols might hang around a few minutes to hours, but eventually fall.
With these caveats, these images nevertheless demonstrate the effectiveness of wearing face masks that cover the nose and mouth.
First, this charming* video of NIST scientist, Matthew E. Staymates, working from home. Note how his breath stays much closer to his head when he wears a mask vs when he doesn't. This is why mask wearing, along with social distancing, dramatically reduces transmission risk. Remember, this is showing hot air; virus-containing droplets will most likely by caught in any type of mask as long as it covers the mouth and nose.
I particularly like that he wears different styles of cloth masks sewn by NIST colleagues, who did socially-distanced handoffs outside his home. All types of masks work as long as they are comfortable enough for you to actually wear them over both your nose and mouth.
This older video demonstrates how much air you exchange with others just in normal face-to-face conversation. It starts with normal nose breathing, then mouth breathing, talking, coughing, conversation, etc.
I'm cautious and minimize my shopping trips. When I go into stores, I use hand sanitizer, then put on my mask and then enter. I don't touch the mask until I get back outside. This protects me. It protects you.
Give people without masks a very wide berth, 2 meters or more, and minimize your exposure to them. If someone takes off their mask to talk in a store, run away. They've contaminated everything within droplet distance. If they talk loudly, that can be far greater than 2 m. If a store allows unmasked people to enter, assume all surfaces are contaminated. (This creates so much more work and risk for retail workers.)
If all staff and shoppers are wearing masks, I would not stress about breaking the 2 m bubble for a short time. Remember, it's also the viral load in a short amount of time that is dangerous. If you get a tiny bit of viral load, and you have a healthy immune system, your body would destroy the viruses before they can get a toe-hold in your respiratory tract.
When I see people wear masks under their nose, I give them wider berth, but don't say anything to them about it. They tried, but maybe they are too uncomfortable. Or maybe they are conspiracy theorists who don't understand that oxygen and carbon dioxide pass through the masks just fine. Either way, I don't want to engage with them. A mask that covers their mouth would still contain droplets expelled by talking unless they sneeze or cough.
For those of us in low-risk settings (not health care workers or people who work around others all day) the best mask is the one you will actually wear. If you try to make it too efficient at filtering, it can be difficult to breath through, or get soggy from your exhaled breath. If you take off your mask when indoors (other than in your own home,) then you lost protection.
I walk and bike outdoors without a mask, but carry one in case it gets crowded. I'm coming around to the idea that perfect is the enemy of good and I may sew lower-coverage masks that don't extend as far across my cheeks for outdoor exercise and gardening. The best mask is the one that you will keep on.
* Maybe I'm biased because I got my PhD at a NIST lab.
Wednesday, June 17, 2020
Monday, June 15, 2020
Undermining science and scientists
The news this week is full of stories of science being undermined by political appointees.
This global map of tropospheric NO2 was produced using data from the Envisat's SCIAMACHY sensor in 2004.
Science funding is very scarce. If you are lucky, you will get one or two opportunities in your scientific lifetime to be involved with a new satellite sensor. Around 2004, I met scientists who were validating and calibrating the SCIAMACHY sensor. They couldn't figure out why they were detecting more NO2 than were supposedly being emitted.
They were working off emissions inventories which took into account all the known emitters of NO2. They knew all the fixed sources like factories and power plants. They could estimate the mobile sources (vehicles) based on the amount of gasoline and diesel sold and the expected emissions from those vehicles. So what was wrong? The emissions inventory (and associated models) or the satellite sensors?
This discrepancy troubled scientists for 10 years while VW and other diesel vehicle manufacturers brazenly lied and cheated. Imagine how much science could have been done if scarce people time and money weren't wasted trying to reconcile pollution measurements to falsified emissions data.
Back then, I had never heard of the term, gas-lighting. Man, I am a member of several routinely gas-lit many groups: women, people of color, scientists. All that fury is bubbling out right now.
Go take a look at these and other figures of NO2 that wasn't supposed to be there.
- Sowing Doubt and Undermining Science
- Disbanded EPA science panel blasts lack of action on particulate matter
- A War Against Climate Science, Waged by Washington’s Rank and File
This global map of tropospheric NO2 was produced using data from the Envisat's SCIAMACHY sensor in 2004.
Science funding is very scarce. If you are lucky, you will get one or two opportunities in your scientific lifetime to be involved with a new satellite sensor. Around 2004, I met scientists who were validating and calibrating the SCIAMACHY sensor. They couldn't figure out why they were detecting more NO2 than were supposedly being emitted.
They were working off emissions inventories which took into account all the known emitters of NO2. They knew all the fixed sources like factories and power plants. They could estimate the mobile sources (vehicles) based on the amount of gasoline and diesel sold and the expected emissions from those vehicles. So what was wrong? The emissions inventory (and associated models) or the satellite sensors?
This discrepancy troubled scientists for 10 years while VW and other diesel vehicle manufacturers brazenly lied and cheated. Imagine how much science could have been done if scarce people time and money weren't wasted trying to reconcile pollution measurements to falsified emissions data.
Back then, I had never heard of the term, gas-lighting. Man, I am a member of several routinely gas-lit many groups: women, people of color, scientists. All that fury is bubbling out right now.
Go take a look at these and other figures of NO2 that wasn't supposed to be there.
Water Rights and Water Rights
If you were to explain legal water rights in the western United States to someone who knows nothing about it, I don't know if they would believe you. It's so ludicrous and steeped in historic inequality, I can't defend it. I wrote a little bit about it in Living history back in 2015.
Our Boulder condo straddles a water ditch, but our HOA does not own the water rights to the rain and snow on our property. In fact, our rain gutters feed into the ditch because some white farmers, back in the 19th century, filed paper claims to the water that falls on our property in perpetuity. If we need water, we have to buy it from them, or someone similar (all white men), who was granted water rights by the white men who ran the government at the time.
Do I have your attention?
Back in April, I posted the first half of my March 2020 report to the LWV/LAC about water safety in Los Angeles County.
Here's the water affordability background and discussion.
Back in 2012, California enacted AB 685, now Water Code Section 106.3. It statutorily recognizes that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” Safe and clean are already defined by multiple water quality laws federal and state. Declaring it doesn't make it so. You have to add some homework and $.
In 2015, that was followed by AB 401, which requires the CA State Board of Equalization and other stakeholders to develop a plan for funding and implementation of the Low-Income Water Rate Assistance Program.
In 2019, SB 200 established the Safe and Affordable Drinking Water Fund to assist low-income Californians. The law spelled out how it would be funded, but the implementation details are still being worked out.
The California Water Board released a report on low-income water affordability to satisfy AB401; related to AB685 and SB200:
Options:
It is absolutely vital that everyone gets water, especially during a pandemic when good sanitation is a life or death matter. But what about the water providers? Some were already struggling financially before the Covid-19 crisis because their customers were already economically struggling. Yet, help from the state from AB401 still hasn't arrived.
The stopgap may be the same solution as for water safety: merging the struggling water service providers to stronger ones. Strong can mean many things, including access to clean water through paper water rights and/or money to purchase water from those that hold paper water rights.
One such scenario is playing out right now in southeastern Los Angeles County. I'm following it closely and will do more research before blogging about it.
Our Boulder condo straddles a water ditch, but our HOA does not own the water rights to the rain and snow on our property. In fact, our rain gutters feed into the ditch because some white farmers, back in the 19th century, filed paper claims to the water that falls on our property in perpetuity. If we need water, we have to buy it from them, or someone similar (all white men), who was granted water rights by the white men who ran the government at the time.
Do I have your attention?
Back in April, I posted the first half of my March 2020 report to the LWV/LAC about water safety in Los Angeles County.
Here's the water affordability background and discussion.
Back in 2012, California enacted AB 685, now Water Code Section 106.3. It statutorily recognizes that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.” Safe and clean are already defined by multiple water quality laws federal and state. Declaring it doesn't make it so. You have to add some homework and $.
In 2015, that was followed by AB 401, which requires the CA State Board of Equalization and other stakeholders to develop a plan for funding and implementation of the Low-Income Water Rate Assistance Program.
In 2019, SB 200 established the Safe and Affordable Drinking Water Fund to assist low-income Californians. The law spelled out how it would be funded, but the implementation details are still being worked out.
The California Water Board released a report on low-income water affordability to satisfy AB401; related to AB685 and SB200:
Options:
- Direct bill assistance (does not help renters whose water bill is included in rent)
- Renters’ water credit (gives help once a year while water bills are monthly; poorer families move more frequently and may not be on lease or receive aid)
- Crisis assistance can be added to either option 1 or 2 and can keep the water from being shut off.
- Set $ assistance per household assumes 3 people at 49 gpd (gallons per person per day) and does not take into account household size.
It is absolutely vital that everyone gets water, especially during a pandemic when good sanitation is a life or death matter. But what about the water providers? Some were already struggling financially before the Covid-19 crisis because their customers were already economically struggling. Yet, help from the state from AB401 still hasn't arrived.
The stopgap may be the same solution as for water safety: merging the struggling water service providers to stronger ones. Strong can mean many things, including access to clean water through paper water rights and/or money to purchase water from those that hold paper water rights.
One such scenario is playing out right now in southeastern Los Angeles County. I'm following it closely and will do more research before blogging about it.
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