Sunday, October 18, 2020

Nuclear Power Context

I had a really good conversation with my daughter about nuclear power this week.  We've been having a lot of conversations about infrastructure and the environment during the voting period while she filled out her ballot.  

[I'm so proud of her doing the research and voting the whole ballot.  At her age, I left some of them blank, especially the down ticket races & obscure government boards, thinking that others were more qualified to decide.  We all know how that worked out.]

Anyway, I wanted to document our discussion in case your kid asks, too.

The federal Energy Information Administration is a font of information.  Hooray for deep state operatives that collate, quality check and make good information available! 


The US generated about 4118 Billion kilowatt hours (kWh) in 2019. It's impossible to know how much electricity is generated by privately-owned solar panels "behind the meter", but EIA estimates there's an additional 35 Billion kWh.  It's a drop in the bucket, but growing.

The largest chunk of carbon-free electricity in the US is from nuclear, 19.7%.  That's slightly larger than the 17.5% generated by renewables.  

If we were all to magically replace our gasoline powered cars with electric ones, we'd need to double our electricity generation.  If we were to close down all the existing nuclear power plants, we'd have to figure out a way to add carbon free electricity at an unprecedented and extremely difficult rate.  If we were to do both, as some people want, I don't know how we will keep the lights on.

Moreover, large hydropower and existing nuclear power plants in the US were all built 40-90 years ago. 25% of our nations' electricity generation capacity is at the end of their design lifetime and need to be replaced along with the 23.5% that comes from coal.

The US doesn't produce solar panels any more.  (It's dirty and dangerous to produce.  It's expensive to produce safely.)  We rely on Chinese imports.  The Chinese government just announced an aggressive schedule to decarbonize their electricity generation, which may mean exporting less panels to the US.

NIMBYs have stymied wind mill deployment around the country.  

California Governor Newsom announced an executive order that all cars sold in California from 2035 and later have to be electric.  That's 15 years from now and our electricity grid is neither ready or on the way to being ready in time. 

We are in serious trouble unless we dramatically reduce the number of cars we drive, the number of miles that we drive and the size/weight of the vehicles.  This is why I'm such a shill for Ebikes.

In California, I spend a lot of time on the California Independent System Operator site viewing daily electricity data*.  Consider August 16, 2020.  It was a particularly hot day.


Due to a combination of factors, there was insufficient electricity and California experienced rolling blackouts in the late afternoon and evening to keep the grid from crashing over wider areas.  Here's CAISO data for energy sources for that day. 

I replotted the data to put the "Green" energy on the bottom and the most carbon-intensive sources at the top.  EIA reported that roughly half the electricity imports to CA in 2019 were carbon-free. I have no idea what other means so I left it at the top.
Here's a detail of the renewables portion:
When the sun goes down, renewable energy plummets while energy demand rapidly rises. This leads to the infamous CA duck curve.  

Filling this need with batteries would take an insane amount of highly toxic and dangerous batteries.  There aren't enough rare earth minerals to make it happen, anyway.

You could fill the need, in an emergency, by releasing water from dams during the evening to generate hydropower.  But, rivers and streams don't exist solely to be our batteries.  Rivers support whole ecosystems that rely on the cooling power of water flow during the hot afternoons.  This mimics the natural rhythm of snowpack melt, stream flow in Sierras.  Moreover, you can't count on having water to release in drought years.

This gets us back to where we started.  On an annual basis, CA gets about 8-10% of our electricity from Diablo Canyon nuclear plant.  Before the closure of San Onofre, nuclear used to provide ~20% of CA's electricity.  San Onofre and the geothermal power plants near the CA-MX border used to provide SoCal with nearly entirely carbon-free electricity at night.



So we talked about how and where Cobalt is mined; nuclear, battery and coal waste problems, tradeoffs of different sources of electricity, and environmental justice.

It made me feel like I was doing my job as a mom.

* I was the type of teenager that got insider (not public) tours of Diablo Canyon and Forsmark nuclear power plants. People knew that I was interested in science and energy/water, and I also finagled my way into places.  That wouldn't happen today.

Saturday, October 17, 2020

Deluxe and Status Anxiety

[I'm going through my drafts folder and found this item from 2007 that I never posted.  I added a link to a recent book and it's time you read what I thought in 2007.]

Kathleen sent me a copy of Deluxe: How Luxury Lost Its Luster. Man, that is a depressing book. In brief, scaling up luxury goods meant moving production to large, new factories in China. The cost of production of the luxury goods plummeted to 10-11% of the retail price. Marketing/advertising overtook production in the total price of luxury goods. 



Mark says that the truly depressing movies are the bad ones. In that vein, I recommend that people also peruse Alain de Botton's Status Anxiety  I was especially moved by this quote from page 82 of the hardback edition:
Rather than a tale of greed, the history of luxury could more accurately be read as a record of emotional trauma. It is the legacy of those who have felt pressured by the disdain of others to add an extraordinary amount to their bare selves in order to signal that they too may lay a claim to love.
Maybe that's confirmation bias.

Anyway, Dana Thomas is a business of fashion reporter with good industry access.  Deluxe and Fashionopolis: The Price of Fast Fashion and the Future of Clothes are both good reads about the opposite ends of the apparel trade.  



Leaf Blowers: Window on Governance

I wanted to do a quick post about something that seems like a small tweak and highly local, but that is much more complicated and far-reaching.  It gives another data point for "all politics is local" and "think globally, act locally."

With great fanfare, Redondo Beach voted to ban motorized leaf blowers on July 10, 2018 on environmental grounds.  The announcement did not explain the environmental grounds or clearly define what they mean by motorized.  

The notices went out to residents, but not the gardeners.  Renters, about half the RB population, don't hire gardeners. I don't know if property managers that hire gardeners were notified. The gardeners seemed to be unaware of the rule.

When I told gardeners about the rule, they ignored me or told me either that they were unaware of the ban, or that their electric leaf blowers were exempt.

The health hazards of gas-powered leaf blowers are well known.  They are deafeningly loud and expose the users to dangerous levels of carcinogens from fuel and combustion by-products.  The California Air Resources Board has a website explaining the pollution caused by Small Off-Road Engines (SORE).

BTW, the smog pollution includes NO2, which is known to be a very potent and persistent greenhouse gas.


1 hour of lawn mower use produces as much smog as driving LA to Vegas.  1 hour of leaf blower use = driving 1100 miles from LA to Denver.

The numbers are staggering. 1 hour of leaf blower use produces as much smog as a RT to visit my mom in SF and continuing on to northern NorCal to visit my SIL. 2 hours = a RT to Boulder to visit friends. 

Newer cars are much cleaner than older cars.  Our hybrid is cleaner than average so the equivalent SORE use time may be much lower.  In 2020, SORE smog emissions will roughly equal total car smog emissions in CA. SORE emissions will dominate as older, more polluting cars are retired. 

Lawn Equipment roughly equal total car smog emissions in CA and will dominate as the old cars are retired. 

The case against gas-powered leaf blowers is easy and well-known.  What about the much quieter electric-powered leaf blowers?  Are they a harmless alternative?

They don't produce the smog, but they are just as effective at kicking up clouds of dust.  Gardeners wear particle masks when they use leaf blowers to protect themselves, but the rest of us choke in it.

What's in that dust?
  • Pollen: terrible for allergy sufferers
  • Mold: terrible for people with allergies and compromised immune systems*
  • Road Dust: toxic, carcinogenic, causes lung & heart disease and dementia, makes Covid-19 deadlier
Let's normalize using a rake with a broom and dust pan.  It doesn't kick up as much dust or throw it up as high.  Reject that ultra-manicured yard look.

* My stepmother died of pneumonia after her last round of chemotherapy.  She was given a strong cocktail of antibiotics and anti-fungals via IV, but they couldn't save her.  An autopsy showed that she died of fungal pneumonia.  Mold spores got into her lungs and took advantage of her weakened state.  I think of her every time I hear or see a leaf blower.




What about governance?

Leaf blowers are another reason I lost faith in my local government.  I thought that you pass a law, and people obey the law.  If they don't, you call the cops or some other watchdog responsible for enforcing the law.

I called the non-emergency police hotline.  They took the report, but did nothing.  I asked my council member.  They said that the police were not happy about working without a contract. Hopefully, they would do more enforcement of laws after contract negotiations were successful.  

[The city was also spinning up another number and email address where we could report leaf blower violations as a workaround for the non responsive police department.  I emailed that office time-stamped photos of leaf blower use on my block, but never got any responses from them either.]

WHUT? Local teachers were working YEARS without a contract, yet they were still doing their jobs. From the Beach Reporter
In the 14 months since Redondo Beach enacted a ban on leaf blowers, the city has received more than 1,700 complaints and issued just three citations. ... On Tuesday, the Redondo Beach City Council received its answer when it learned that out of more than 1,375 leaf blower complaints to city code enforcement just two citations were issued. Police issued one citation out of 339 complaints. Numerous courtesy notices were also issued.
Up to that point, I had very few interactions with the RB police. Now, with all the BLM and Defund the Police talk, I've been thinking about what functions are appropriate for the police and which would be more effectively dealt with by others. 

Have you looked at your city's budget? I mean really looked at both the discretionary budget and the zombie costs of pensions? Do you know about the VERY generous police pensions relative to all other types of government jobs? They literally have a gun pointed at our heads during contract negotiations. 

Anyway, this has changed the way I see the police and city budgets. It's also changed the way I see local political races and endorsements from police (and fire) unions.  The saga with the RB firemans' union going after the elected officials that refused to merge with the county fire department (and their platinum-plated pension program) was eye-opening.


Even after cutting $150 M, LAPD still gets more than half the city's unrestricted funds.  If you count pension contributions, and they have the most generous pensions, police departments get the lions share of most city budgets.  

The cities work for the police departments, not the other way around.

Moreover, these employees often don't live in the cities where they serve.  They take that money and spend it elsewhere.  It's not an exaggeration to call it colonialism.

It started with my allergies and leaf blowers.  But it made this suburban mom question who really works for whom.  My local police union** taught me a lesson, and it wasn't the one they intended.  When the Defund the Police movement arrived, I was ready to listen.  

**The police union and the police chief are not equivalent. They don't have the same priorities.

Thursday, October 01, 2020

What's your Voting Plan?

I read this 2020 Asian American Voter Survey and got depressed thinking about all the people who don't have a voting plan yet.

Democracy in the US is in peril & it is up to all of us to save it. Under some metrics, North Carolina is no longer classified as a democracy.
An independent academic study founded in 2012, the Electoral Integrity Project addresses three questions:
  • When do elections meet international standards of electoral integrity?
  • What happens when elections fail to do so?
  • And what can be done to mitigate these problems?
Under the direction of Professor Pippa Norris and the distinguished International Advisory Board, the Electoral Integrity Project produces innovative and policy-relevant research comparing elections worldwide. The research team is based at Harvard University's John F. Kennedy School of Government.
Was it a fair election? The answer is more than a simple yes or no.  Election integrity is more of a continuum.
Elections are just one of the pillars of democracy.  Another pillar is an informed electorate.  I blog about topics that I don't see in the press, or that I don't feel were treated with adequate nuance.  So, in a sense, my blog is an affirmation of my optimism for democracy.  If more people knew the facts, they could react more optimally to ensure better outcomes for everyone.

It's fair to say, this has been wildly optimistic.  Nevertheless, I persist.  Suppose you have never voted before, or are trying to convince friends and family to become voters, where do you get started?

First, you should get your information from high-quality sources.  In a functioning democracy, you would start with the people who run your elections.  For instance, the California Secretary of State runs the state elections.  The Los Angeles County Registrar-Recorder/County Clerk runs the LA County elections.  Finally, the Los Angles City Clerk runs the city elections.

[Substitute your jurisdictions to search for the official sites.]

In Los Angeles County, the county clerk coordinates the ballots and voting for all 88 cities in the county.  It's a huge undertaking as LA Co is both the most populous (10 Million) and the most complex (language diversity) county in the US.
Mandated Languages
Los Angeles County is currently required to provide the following language assistance to VRA voters in addition to English:

•Armenian
•Chinese
•Cambodian/Khmer
•Farsi
•Korean
•Spanish
•Tagalog/Filipino
•Vietnamese
•Hindi
•Japanese
•Thai
•Russian
•Bengali*
•Burmese*
•Gujarati*
•Indonesian*
•Mongolian*
•Telugu*
The full list of LA County Vote Centers just went live on 10/1/2020. Some are open 5 days (10/30-11/03) and others are open 11 days (10/24-11/03.) The list of over 400 secure Ballot Drop Box locations will be released shortly.  If you are a registered voter in CA, your ballot will be mailed to you.  You can mail it back, or drop it off at a Ballot Drop Box or Vote Center.

When I was eligible to vote for the first time, I was an 18 year old college freshman.  I only knew what my teachers and parents told me, and some of what they said were contradictory.  My fellow students pretended to know the answers, but their information was also suspect.

Various groups were after my vote and bombarded our dorm mail room with pamphlets.  I read and tossed all but one.  The League of Women Voters (whom I had never heard of up to that point) left a brochure that explained each initiative (and CA has a lot of them) in plain English and then listed the Pros and Cons of each of them.

The LWV wasn't after my vote.  They wanted to educate me.  I've used their brochures ever since.  Printing brochures is expensive, so most of it is online.  I'm providing links and explaining the differences between the different sites.

[Aside: Non-partisan means LWV does not endorse or oppose any particular political party or candidate.  LWV also works really hard not to be biased.  LWVC is a registered 501(c)(3) and 501(c)(4), which means it does education AND advocacy and I'll get to the advocacy part below.]

You can always start at the LWV US (national) level site at lwv.org and then navigate to your particular states' site.  In my case, that would be lwvc.org.  Follow the links on the right column for the Voter Toolbox for instructions on the logistics of how to vote in your area. You can even Register to Vote online.


Underneath the Voters Toolbox, you will find the CA Voter's Edge widget. (In other states, go to vote411.org for your state-specific information.)

Type in your zip code (your street address is optional) and click on the green "Find my ballot" button.  The site will query a database and return with every single item you are eligible to vote on in the upcoming election (Federal, State, County, City, special Districts.)

LWV volunteers in every community contact candidates running for office and send them written questionnaires and invitations to upload their bios and other informational data.  (I admit to being a bit biased here, but I think that a candidate that refuses, or is too disorganized, to provide information maybe shouldn't be in public office.)

I usually take my sample ballot, sit in front of my computer, read the candidate stuff, and mark my selections on my sample ballot.  In pre-Covid days, I brought my sample ballot to the Vote Center with me and entered in my selections on the touch screen.  This time, I will be using copying my selections from my sample ballot to my actual ballot, which should be arriving this week in the mail.

CA Easy Voter Guide  is your quick-start guide to general information about the election and plain English explanations of what each CA proposition means. Search on your state's Easy Voter Guide if you live in another state.

votersedge.org or vote411.org gives you your customized ballot information.

The Pros & Cons lay out unbiased information about each initiative.


The advocacy arm sometimes decides to take sides on initiatives (but never on candidates.)

Vote with the League provides arguments on why we hope you will side with us on some issues.

Volunteers analyze, organize, upload and sometimes write all of these materials. The decision to advocate on some initiatives is taken by a committee. (Disclaimer, I have provided research and facts for the committee to consider.) Generally, I think these are pretty good recommendations. 

Occasionally, I feel more strongly on an issue that the committee stayed neutral on (or vice versa.) But, I've never had a strong disagreement, which is pretty remarkable, and why I joined the organization as a volunteer.  If partisan politics isn't your thing and you want to be politically involved with a group that values facts, evidence and expertise, then check out your local LWV chapter.

If you are a California voter, Vote Yes on Prop 15: Schools & Communities First. Don't listen to the propaganda.  It only applies to commercial (not residential or agricultural) properties.  Make Apple and Genentech pay property taxes on the real value of their corporate campuses.


Aside (written weeks ago, may repeat above info):
When I was approaching my very first election as an 18 year old UC Berkeley Freshman, I found a LWVC Pros and Cons printed pamphlet outside my dorm along with lots of flyers from myriad groups telling me to vote this way or that way.  I read them all with a critical eye and the LWV stood out from the rest.  Clear, evidence-based discussion of the issues and what our votes will mean.

As an immigrant, I wasn't familiar with the LWV or the other groups vying for my vote.  Before the internet, you couldn't just look up the LWV history or learn how to join.

I was and am a science nerd.  I did not participate in student government at any level.  It didn't occur to me that LWV needs science nerds until a fellow math major invited me to a meeting.   We discussed a specialized field called voting methods that involved lots of math and computer science.  Everyone there was a teacher and/or a technical person and made me feel welcome.

I signed up to join both the voting methods team and the local chapter.  I went to a general meeting, and found myself helping to write the next Pros and Cons and Vote with the League information for the upcoming election (on a highly technical issue that frequently gets reduced to sound bites).

Pros and Cons is purely informational and lays out all the factual arguments to support or oppose measures.  Lies, distortions and wishful thinking are not tolerated. Facts, context and history with as little bias as possible given human writers and editors.

Vote with the League adds recommendations, if any.  After examining all the evidence and Pros & Cons, the League may feel so strongly that it will make recommendations.  Sometimes, the evidence is mixed and the League will stay neutral.  If there is not enough information or the League lacks the specific policy positions to take a stand, we won't.

LA Times posted their guide:
Here’s everything to know about voting by mail in Los Angeles County

Monday, August 17, 2020

Face Mask Science 3, August 2020 edition

Do you have face mask confusion?  Do conflicting headlines give you headaches?

I sort of feel like I've read enough to know that I should wear one whenever I am indoors in any place that is not my own home.  I should also carry one whenever I am outdoors and be ready to put it on whenever anyone is nearby.

There is no way to reduce risk 100%, but we can reduce it to pretty low by:

  • Social distancing in the sense that we minimize going out where we could encounter other people--especially in poorly-ventilated indoor places
  • Social distancing in the sense of putting as much space (and air) between you and others outside your household when you do go out
  • Universal mask wearing, especially indoors
  • Good hygiene (cleaning surfaces, washing hands, not touching face, etc)

The even better news is emerging evidence from multiple countries and situations/studies that show that universal masking reduces the severity of Covid-19 illness if you do catch it. The idea is that viral load matters.  The higher the viral load, the more severe the illness. 

  • Try to avoid situations where you can be exposed to the virus.  
  • Assume that everyone is contagious (even though usually, it's less than 1%, often much less than 1% of the population.) 
  • Then minimize your exposure.

The shaped 2-layer cotton masks I sew are fine for essential shopping trips and the occasional doctor visit.  The problem is finding masks that are comfortable enough to wear when being active (walking, biking, gardening.)

I made some gaiter-style masks with poly/lycra knit sewn into a tube, with a ponytail port at each end.  They were comfortable enough to wear for exercise, but a recent article said that gaiter masks might be worse than nothing.  That made no sense.

Fortunately, Professor Brent Stephens wrote 6000 words about what we know and don't know about masks, different materials, and Covid-19. What kind of mask should I be wearing to protect against COVID-19?

He has some thoughts on Gaiter-Gate, which I need not replicate here. Go read his analysis on why that gaiter measurement (with no control) is highly suspect.  Other scientists pointed out that the measurement that showed a "fleece gaiter" was worse than a bare face at containing droplets might have been measuring fleece fiber shedding instead of droplets.

Professor Linsey Marr wrote how she runs with a gaiter and doubles it up when anyone is nearby.  She posted a presentation on the blocking efficiency of neck gaiters.  The bottom line is that the thin kind that I sew blocks 50-90% of particle sizes that matter when worn in a single layer.  When doubled over, they block 90% over the entire range.

Lab setup:


The data:


The airbrush and spray bottle produce large droplets that, in the absence of a mask or neck gaiter, land on glass slides attached to the opposite manikin’s face. When either neck gaiter was affixed to the spraying manikin, no droplets were observed on the opposite manikin. Thus, the neck gaiters are 100% efficient at blocking these droplets from reaching the opposite manikin’s face.



I know that I sound like a broken record, but the best mask is the one that you will keep on.

Anyway, I am heartened from all of this advice from scientific experts.  It makes Covid-19 less scary.  I have enough to worry about with the elections and the census. 

In other news, this pandemic has made me read up on indoor ventilation and reminded me of sick building syndrome.  I was the canary in the goldmine for that and remember being treated like I was crazy.  One doctor even told me that he ordinarily sends patients who present with my symptoms to psychiatrists but he didn't think that was my problem; after all, I don't dislike technology and chemicals if I decided to major in it.  I'm assembling a blog post with very interesting things I learned.  I even ordered test equipment for my home. 

The mask series.

Friday, July 17, 2020

Road noise and what we can do about it

I'm really noise sensitive.  Perhaps you are, too.  I did some research reading and am collating it here.

(My local main street of Artesia Boulevard is painfully loud.  My ears ring after I've walked more than a couple of blocks along it.)

First off, I found a recently published book that has an entire chapter about Traffic Noise By Sanja Grubesa and Mia Suhanek. BTW, I just learned about IntechOpen, an open access science book publisher. This is so much better than the for-profit model. I'm looking at you, Elsevier Press.

Brubesa and Suhanek wrote a concise and excellent chapter. I'm excerpting a little bit but I hope you click on the link and read it yourself.
Road traffic noise depends on the following three factors:
  • Type of road vehicles.
  • Friction between the vehicle wheels and the road surface.
  • Driving style and driver behavior.
What types of vehicles?  In general, bigger vehicles produce more noise.

Electric vehicles don't produce any engine noise. Some hybrids run in all electric mode at low speeds (below 10 mph for our family's car.)  In congested city driving, electric and hybrid cars reduce traffic noise relative to normal ICE, Internal Combustion Engine, ones.

Vehicles also produce wind noise from the turbulent air that they produce as they travel.  Blocky vehicles create more turbulence.  Aerodynamic ones produce less.  Many economy cars and older minivans are wedges on wheels, delivering better fuel economy and less noise than trucks and SUVs.

The fashion for making minivans "cooler" by shaping their front ends to be more vertical and blocky like SUVs is so bad for noise, fuel economy and public safety for everyone outside the vehicle.  SMDH

Tire noise is a major noise generator.  Tread matters.  If you ride a bike, listen to the difference between smooth and knobby tires.  Car tires are similar, only the car cabin insulates you from having to hear the noise of your tires.  Everyone outside your car notices and is cursing you.

In general, the larger the tire-street contact area, the bigger the noise.  So you may buy the bigger tires for more cabin comfort/smoothness, but you are creating more friction and making more noise.

The heavier the vehicle, the greater the noise.  So EVs have silent engines, but may have greater tire noise.  To have decent driving range, their batteries are heavier than carrying an engine and a tank of gasoline.

The faster the driving, the greater the wind noise.  That's why Noise Increases with Vehicle Speed.


At 30 mph, a typical auto may produce 62 decibels, about the noise of a human conversation. At 54 mph, the same auto would produce 72 decibels. Decibels are a logarithmic scale so an increase of 10 decibels is a doubling of noise.

California had an 85% rule.  The fastest 15% of drivers determines the new speed limit.  Over time, the speed limits on urban arterials climbed from 35 to 40 to 45.  This has been a disaster for road safety for people outside of cars.  It's also made cities noisier.

What can you do about road noise?
  • Reduce the number of cars.  Pedestrians and bicyclists are mostly silent.
  • Lower speed limits and enforce them.
  • Reduce vehicle sizes with sticks and carrots.  People are using cars much too big for their daily needs. (They can rent larger vehicles as needed.)
  • Increase the distance between noise generators and people.  
  • This and the next 2 figures are from this Traffic Noise Factsheet
  • Replace a car traffic lane with a protected bicycle lane and wider sidewalk. The bike lane protector is a low wall that protects the bicyclists from swerving automobiles and creates a noise shadow. A waist-high wall can make the stores & restaurants along arterials much quieter

Trees don't do anything to reduce noise, but they provide much-needed shade to counter the urban heat island effect.

Speaking of urban heat islands, ICEs produce a lot of heat.  Burn anything and it produces heat. Reducing the amount of ICEs on the streets, and making engines smaller would reduce urban heat, noise and air pollution and climate change.

Related:

Thursday, July 16, 2020

More face mask science

I'm emotionally exhausted by the pandemic and all the crappy news.  I've posted links to useful Covid-19 information when I come across them on microblogging platforms like IG and Twitter.  It's just easier than blogging.  But, there is also value to putting it on a blog, with more context and explanations.

I've written about masks in The mask/no mask dilemma back on March 18, when some US government messaging was that masks were not effective for the lay public. A lot of people have written about that bad messaging and I'm not going to belabor it here.  Professor Zeynep Tufecki does it as well as anyone.

Anyway, I also posted some cool visual proof of the efficacy of masks in This is why we wear masks. Those are Schlieren images and show breath vapor, not the motion of aerosols and droplets, which will stay even closer than the images shown.

Almost any type of cloth face covering will catch droplets. Most multi-layered ones will catch the majority of the aerosols as well. Masks hold your air closer to your face than without masks.

As Dr Lucy Jones says, "don't share your air."

In my first post, I (and many readers) didn't know what they meant by "Cotton Mix" but were impressed by its filtration efficacy.


After reading this subsequent article, I learned that it was Cotton/Poly blend. Polyester, and any fabric that has static cling, has electrostatic properties that attract and hold particles. That's why your furnace filter is made of polyester fabric. In fact, some people were buying furnace filters and cutting them up to insert inside their DIY masks.

Read Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks. I excerpted some figures and a table from the paper. Even though it is published in a scientific journal, it's written so they lay public can understand it. It is freely available and I hope you download and read it. It's good.
We have carried out these studies for several common fabrics including cotton, silk, chiffon, flannel, various synthetics, and their combinations. Although the filtration efficiencies for various fabrics when a single layer was used ranged from 5 to 80% and 5 to 95% for particle sizes of <300 and="" nm="">300 nm, respectively, the efficiencies improved when multiple layers were used and when using a specific combination of different fabrics. 
This figure shows that filters can trap particles by either mechanical filtration (tight weave) or by electrostatic attraction.

Cotton, the most widely used material for cloth masks performs better at higher weave densities (i.e., thread count) and can make a significant difference in filtration efficiencies.
Notice that Cotton Quilt fabric (medium weave 120 threads per inch) performs better overall than the 600 threads per inch Cotton except at larger particle sizes?  Looser weave Cotton (cheaper quilting cotton at 80 threads per inch) does a lousy job.
Filtration efficiencies of the hybrids (such as cotton–silk, cotton–chiffon, cotton–flannel) was >80% (for particles <300 and="" nm="">90% (for particles >300 nm). We speculate that the enhanced performance of the hybrids is likely due to the combined effect of mechanical and electrostatic-based filtration.
The hybrids do a better job than pure Cotton. Some even outperform surgical masks, which were never designed to catch smaller particles.  (They were designed to catch larger droplets exhaled by health care workers to protect the patients.)

Our studies also imply that gaps (as caused by an improper fit of the mask) can result in over a 60% decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of “fit” and leakage, while allowing the exhaled air to vent efficiently.
The biggest factor is fit. Isn't that the #1 reason why we sew?  We can customize the fit.

We also sew for improved comfort and face masks are no exception.  If the mask fits and is comfortable, we can wear them for as long as we need.

Pay attention to the pressure drop.  It doesn't matter if the weave and fit are tight, but it's too hot and uncomfortable to wear.  I know that I can wear a real surgical mask while riding my bike or for a long-haul airplane flight.  So I want a combo that has a similar pressure drop of 2.5.  I'll sew something with a good enough filtration efficiency, with the same comfort rating.

Overall, we find that combinations of various commonly available fabrics used in cloth masks can potentially provide significant protection against the transmission of aerosol particles.
Notice that, in every case, more layers offers more protection. 

If you read up on Brownian motion, you learn that smaller particles move faster and encounter more obstacles than larger particles.  So your fabric or filter material doesn't have to be tight enough to mechanically trap the smallest aerosols.  A filter can alter the particle trajectory so that it comes at a slant instead of perpendicular to the filter.  That makes the particle more likely to be caught by subsequent layers. 

That's the magic behind multiple layers.

Knit fabric structure kind of has those layer properties, which is why just one layer of t-shirt jersey can be effective.  Aerosol expert, Professor Linsey Marr, Tweeted that she wears a knit gaiter-style mask single layer when running outside and then doubles it up (by rolling the top over her nose and mouth) if anyone is nearby.

I've come to the realization that I need a wardrobe of masks for different situations.  I'll make some knit gaiter ones for outdoor exercise.  I'll make some fitted woven ones for my essential trips to indoor locales.

It's time to bust out all my cotton/poly or cotton/silk mixes for fitted masks and some high-performance poly knits for gaiters.

I wear a mask to protect you. You wear a mask to protect me. We can sew our own and make it a fashion statement.

Finally, read Masks offer much more protection against coronavirus than many think. Even if the mask is not 100% efficient at filtering out aerosols and droplets containing Coronavirus, it reduces the dose of exposure. So, even if we do get sick, the illness is milder.

"Perfect is the enemy of good," means that waiting for perfection to act is a bad strategy.  We can always strive to do better, learn more.  But we already know enough and have the tools to reduce our collective risk by a huge amount.  Let's all be good enough and defeat this pandemic.

Wednesday, June 17, 2020

This is why we wear masks

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.

Monday, June 15, 2020

Undermining science and scientists

The news this week is full of stories of science being undermined by political appointees.
I'm cleaning up browser tabs and came across a story I meant to write about 5 years ago. In 2015, I wrote VW and the dark side of AI about how VW was cheating on diesel engine smog tests.

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:
  1. Direct bill assistance (does not help renters whose water bill is included in rent)
  2. 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)
  3. Crisis assistance can be added to either option 1 or 2 and can keep the water from being shut off.
  4. Set $ assistance per household assumes 3 people at 49 gpd (gallons per person per day) and does not take into account household size.
Shortly after this report came out, Covid-19 hit.  Governor Newsom issued an executive order that protects homes and small businesses from water shutoffs for non-payment during the pandemic.  Water service providers still have to purchase and provide water, but they may not necessarily get paid for it.

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.