# Air Pollution - Types, Sources, and Fixes

I finished my PhD last week. Today I start posting again. This is a month-long series, one post each week, regarding air pollution and our health. First, we discuss types of pollution, then the health effects of different types based on where you live (US vs. China as case studies), then we move on to the health effects of each type, finally we end on how you filter it.

Hint: Two posts ago (and over a year ago) I said I wasÂ taking a break to build a better pollution filter. I did that, and the final post in the series will be telling you all about that part. In the meantime, please go to www.getblueskies.com, sign up for our upcoming release emails (which will let you know when we launch on indiegogo with a discount for the first buyers), and share our website with your friends that might be interested.

###### Air Pollution

I was speaking with a physician about air pollution, and about which types cause asthma, and she was stunned that there is background research indicating that different types of outdoor pollution have differing relationships with asthma.Â Part of the reason for this was that she didn't realize how easy it was to differentiate which types of pollution come from which sources.

Okay, then. There are several major types of pollution. And NO2 from traffic is far and away the outdoor pollutant that that is most highly associated with our increasing asthma rates in the US (more on this in a future post).

###### Major Pollution Types

Particulate Matter is big chunky pollution. It is called PM10, or PM2.5, for how wide it is. PM10 is 10 microns wide, PM2.5 is 2.5 microns wide. For comparison,Â the average human hair is on the order of 100 microns wide (thin hair is about 17 microns, thick hair is up to 180). PM can be dust, fine soot, pet dander, or pest droppings (think cockroach poop). These can be very easily filtered with HEPA-style filters (HEPA filters are physical filters that block large pollution particles using small holes).

A photo from my time in China. PM pollution is pollution you can see.

Chemical Pollution is very defined and very small. It's specific molecules. It's about 10,000 times smaller than PM2.5. It's also about the size of the the air we breathe, so you can't physically filter it. It is things that you've heard of, like CO (carbon monoxide), SO2, and NO2 (these both become strong acids in water, which causes acid rain. Note that our lungs are about 100% humid air, so they become strong acids, like battery acid, in your airways). These are extremely difficult to filter, and tend to require chemical reactions (more on that on a later post!). We are focusing on SO2, which just comes with fossil fuels, and NO2, which comes about every time you burn something in our atmosphere (our atmosphere is 78% nitrogen, and 21% oxygen, when you burn things, it uses the oxygen to convert stuff into CO2 and other emissions, but at high heats, it also produces NO2. Higher heats means more NO2). We ignore CO for now, and we ignore CO2 because it doesn't cause immediate health threats compared to these other pollutants.

Cars emit a lot of NO2. Catalytic converters help, but they still produce NO2 in amounts that are harmful

VOCs are complicated. They are typically things you smell, like the new car smell, new elevators, paint, permanent markers, etc. Some people are highly sensitive or allergic to these. They can typically be filtered by most activated charcoal filters, because the carbon radicals in VOCs tend to adsorb well onto charcoal (ie they bond to it). We are going to ignore this, because we're assuming you don't like to leave your child in a freshly painted room, in new cars, or on new elevators.

###### Pollution Sources and Types

Hokay, so, now we need to discuss which pollution sources produce each. So I've made this helpful chart. These are relative amounts of pollution within their category, with no clearÂ scaling criteria, but it gives you an idea of how different vehicles or power sources relate in terms of pollution. In other words, a two stroke engine clearly doesn't produce as much pollution as a coal fired power plantÂ More important, these areÂ rough relationships. You can have a wide range in each category, with a coal plant with no controls that burns high-quality coal producing significantly less pollution than the same design coal plant that burns low quality coal, for example.

Chart with differing sources of pollution, and relative amounts of pollution produced by each.

Let's go through this one-by-one.

Vehicles burn gasoline or diesel. Gasoline vehicles pretty much just produce NO2 (and CO! But we are ignoring that for now), and our catalytic converters help reduce that. Smog is a byproduct of NO2 interacting with other pollutants that are already in the air. The part of smog that we see is actually PM pollution, rather than chemical pollution. Diesel vehicles produce a lot PM, and some SO2, and relatively more NO2. Catalytic converters can reduce NO2. Using low-sulfur diesel can reduce SO2.Â A lot of developing countries do not use low-sulfur diesel or catalytic converters, so they produce a ton more of every type of pollution.Â Two Stroke Engines are common in India (and other places, but not so much in China, and almost never in developed countries, unless you count lawnmowers). These things burn oil alongside gas. They produce nasty fumes, like your weedwacker or small lawnmowers. This is part of the reason that India has a particularly nasty type of air pollution. These are being phased out over time, with bans on new models of two-stroke engines in many cities.

Power Plants are a lot more complicated. In the next post, I will be discussing pollution controls in power plants in more detail. Put simply,Â natural gas powerplants produce predominantly NO2. They burn CH4, and convert it to CO2 and H2O.Â NO2 emissions can easily be reduced by 90% with proper controls (discussed in the next post).Â Coal fired power plants can be nasty. With no controls and with using low-cost coal, they produce a lot of each type of pollution. PM is the result of impurities in the coal that can't be burnt, or unburnt specs of coal. Low-grade coal produces prodigious amounts of PM, and contains a lot of sulfur that burns to produce SO2. They produce a lot of NO2. All of this can be reduced greatly simply by building in controlling systems. These controlling systems are used in nearly every coal plant in developed countries and in many coal plants in advanced developing countries. They are completely ignored in nearly every coal plant in many developing countries.

## Traffic Pollution vs. Power Plant Pollution

Which of these should you care about? That depends on where you live. Most of the pollution in developing countries comes from power plants, but if you live next to a busy street or highway, traffic pollution could be the bigger concern. If you are in a developed country, particularly the US, traffic pollution is almost always the largest concern. Why? Because you are sitting directly next to the source. Whether you're biking or walking with your infant in a stroller, you are right next to the pollution. The problem exacerbates when you are nearby to a highway or major intersection, because there is a ton of traffic.

So, in short, if you are in the US and much of Europe, you should be worrying about the invisible (but smellable) traffic pollution that you are breathing in. If you are outside the US, it varies country by country. If you are in China or India, you need to be concerned about both traffic and powerplant pollution, and there is pretty much no escaping it.

- Jason Munster

# Adele and Hello - Math and a Carbon Footprint Analysis

I mentioned I wasn't going to post about the environment as much anymore, but I can't stop. I honestly started this just to show how fun math can be in looking at the number of views on Adele's Hello on youtube. It ended up with me being curious what the environmental impact was.

So today I looked at the youtube video of this song. For your convenience, here it is so you can listen to it while reading this post. Apparently it's blowing up, with an insane number of views per day.

It has 309,000,000 views and has been up for all of 20 days. Let's use some basic math to figure out how popular this song is!

Let's first see how many seconds there are in a day.

$24 \frac{hr}{day} \cdot 60 \frac{min}{hr} \cdot 60 \frac{sec}{min} = 86,400 \frac{sec}{day}$

And over 20 days:

$86,400 \frac{sec}{day} \cdot 20 days = 1,728,000 seconds$

With 309,000,000 views in that time, we end up with 178 views initiated per second, on average, for 20 days, nonstop.

But, hold up, it takes 6 minutes for this song to complete. So that means, on average, there are:

$6 min \cdot 60 \frac{sec}{min} \cdot 178 \frac{views}{sec} = 64,000$

Let's round that up to 65,000. On average, at any given time, there are 65,000 people watching the Adele Hello video on youtube. There are 15 million views per day. That's just one video on one source. In eight whole day, as many people listen to the song,Â on just youtube,Â as watch the superbowl.

If this clip keeps up (which is unlikely), she will surpass Gangam Style, with over 2 billion views, in less than 150 days. And medical stocks will go up, cause I worry that listening to this song tooÂ frequently may drive people into depression.

"But Jay," you say, "what about the energy and environment component?!?"

Let's figure out Adele's carbon footprint from youtube! Let's assume that Google's hosting emissions are negligible. Let's just focus on the energy used for a laptop. Let's say that it is 50W (this is conservative).

From a prior post, we know that a 100W lightbulb uses ~1kg of coal per day. So a laptop will use about 0.5kg per day. How much CO2 is this?

This is basic chem! Let's get really basic. Coal is mostly made up of carbon. So when it is burnt, every carbon molecule breaks off and bonds with O2. So we assume that all 0.5kg of carbon becomes CO2. You need to add that weight of the O2. C weighs 12 AMU (atomic mass units, pretty much the mass of a single molecule) and O2 weighs 32 AMU.

So we need to multiply the weight of coal, which is pure carbon, by the proportional increase of mass of CO2, cause each carbon atom gains O2 weight (12+32=44)

$0.5 kg-CO_2 \cdot \frac{44}{12} = 1.85 \frac{kg-CO_2}{day}$ for a 50 watt computer running all the time.

Also this song is 6 minutes, or 1/10th an hour, and an hour is 1/24th a day, so this song takes 1/240th of a day.

$1.85 \frac{kg-CO_2}{day} * \frac{1}{240} = .00771 \frac{kg-CO_2}{view}$

Don't forget, though, that we have 15,000,000 views per day!

$0.00771 \frac{kg-CO_2}{view} \cdot 15,000,000 \frac{views}{day} = 115625 \frac{kg-CO_2}{day}$

Or, you know, ~125 tons of CO2 per day. Just from Youtube and Adele. This is the generation rate of about 2000 Americans.

And why this analysis overestimates Youtube's and Adele's contribution to CO2 emissions

Most people are multi-tasking while listening to Adele (ie those 50 watts they are using are also going towards whatever else they do while listening to Adele, such as reaching for tissues to blot their tears), so you have to take a fraction of this number Â ðŸ™‚

Second, much of the power use in the US is now coming from natural gas, which is more efficient than coal, so you can cut down this number.

Third, tissues take a whole lot of energy to make. I'm betting that the raw number of tissues used while listening to Adele will increase the CO2 footprint.

How many times did you restart the song while reading this blog, BTW?

- Jason Munster

# Tesla's Powerwall - Not Economical

Tesla Powerwall

I'm gonna open by saying that I really like Tesla's powerpack. Technology isn't pushed past the bleeding edge without loss-leaders pioneering. That being said, the numbers, as usual, don't lie. On a per-unit-energy cost basis, these things aren't economic in most of the US. Once you consider the externalities, however, the overall benefit does make them "profitable." Likely you will see subsidies to internalize these externalities, thus making the powerpack work.

Unless the inverter costs too much. More on that later.

One major implication I haven't seen anyone talk about? Utility companies currently have to pay people with solar panels who produce excess electricity at market rates. They've been trying to get rid of this for years.Â This technology gives utilities every reason to demand they no longer pay people for their excess produced solar power. This has enormous implications. It's now indefensible to force utilities to buy at market rates the extra power produced by homes with solar. Read more near the bottom.

Tesla's Powerwall next to a car. Small-ish and sleek. 7 inches deep, weighing 220 lbs

# What is this Powerwall?

Powerwall is a power pack that you hang on your wall. It costs $3,000 for a 7kwh pack designed for a daily cycle, meaning it's charged and used once per day. This is the cost without installation. Also, this is the cost if you already have solar cells and an inverter. If you want to work with the grid alone, you have to buy an inverter*. Even if you already have solar cells and don't need an inverter, this seems like it's a product designed for the wealthy. Let's look at the math (my favorite part!) *Inverters. Batteries and solar panels produce DC current, or Direct Current. This means it doesn't change phase. What we use in our homes is Alternating Current or AC. The alternating current means that the positive and negative terminals switch sides of the power plug. In the US, they switch sides 60 times per second. DC means that the terminals do not switch sides. Hence batteries having a + and - terminal, and all your non-battery electronics not having these. The Maths! We are going to make some of the rosiest assumptions in the world. First, though, let's get some solid data lines up. Take a peak at NPR's cost of electricity infos. 1. On average, people pay 12 cents per kwh of electricity 2. In Hawaii, they pay 33 cents. We'll use this as a case study. 3. The Northeast and California, two other case studies, pay about 16 cents. 4. The average American uses 900kwh of electricity per month in their home (from eia.gov). Really rosy assumptions 1.Â The sun shines for 300 days a year and provides enough electricity to power your house during shining and to fully charge the battery 2. The electricity grid doesn't buy back your excess solar*. If they do have to buy it back, then the economics discussed here don't play out 3. You've already paid for all of your solar installation and you aren't concerned about those costs of that electricity going into this powerpack 4. These things don't degrade over time (extremely rosy assumption) Hokay! 300 days per year of 7kwh of electricity provided by this beast is: $300 \frac{days}{yr} \cdot 7 \frac{kwh}{day} \cdot = 2100 \frac{kwh}{yr}$ So 2100 kwh/year. What's that get you in most of the US? $\ 0.12 \cdot 2100 = \ 252$ So$252 per year. For a $3000 battery pack. In most of the US, if your solar panels worked perfectly for 300 days a year, it'd take you 12 years to pay back your investment. This is a 6% annualized ROI (Return On Investment). In other words, you'd make more money in the stock market, so it's a bad investment, not even accounting for installation costs and with impractically rosy assumptions, in most of the US. What about in the Northeast and California, where electricity is$0.16?

$\ 0.16 \cdot 2100 =\ 336$

Or payback in 9 years. This is an 8% ROI, making it a decent investment.

Let's be realistic, though. In the Northeast, we have storms and winter. Solar panels don't work so great here. We aren't getting 300 cycles per year out of this. We'd be lucky to get 150, making it an 18 year payback, or about a 3% ROI. What about California? They actually might get 300 days of viable sun a year. So in California, you could be break-even.

Now what's the problem here? Normal people don't look for 8% ROI on their home upgrades. They look for 15%. Pretty much they want 3-5 year payback periods. So pretty much, someone has to have a very green outlook on life to buy one of these. Or there have to be subsidies (more later)

Hawaii

Hawaii has sunshine and electricity costs 33 cents. Let's say you've paid off your solar panels in Hawaii.

$\ 0.33.2 \cdot 2100 =\ 700$

In Hawaii, with our rosy assumptions and no installation cost, the powerpack will pay for itself in 4.25 years, for a whopping 18% return on investment, without any subsidies. There is a viable business model here.

Seriously, someone go start a powerpack/solar panel installation company in Hawaii.

Anywhere else, and these things will need hefty subsidies.

Subsidies

Why would you subsidize these things? Easy. There are only two reliable power sources that can compensate for variability in solar power: hydro and natural gas. Every other power plant takes far too long to spin up to be useful. In other words, nuclear power doesn't stop producing pretty much ever. Coal power takes about a day to get to capacity, so it can't cycle well.
Hydro power is a limited resource. We are pretty much tapped out in the US, and what we have is already being used, so it can't ramp. We'd have to replace what's currently being used with coal, natural gas, or nuclear to use hydro for solar-grid reliability, so that entirely defeats the point.
Natural gas ramps quickly, and we have excess capacity in the US. Natural gas still produces CO2 that spreads globally, and NO2 that spreads locally. NO2 becomes a strong acid when you breath it in, so we have healthcare reasons to reduce it. Thus it might make sense to subsidize these powerpacks to make people more likely to buy them.
Second, this is good tech. It's pretty much where it needs to be in order to make sense to buy in many parts of the country, if you already have solar. Subsidizing it will cause further advancement in battery tech, making it that much more viable in a wider array of applications. Battery tech is one of the things holding us back from so many viable technology applications, so if there is something to subsidize that will more than pay for itself, it is battery tech that is nearly cost-even now.
Some Extra Thoughts on my Rosy Assumptions
*If Solar Companies don't need to buy back Electricity
In most places, if you produce excess electricity that you don't use, the solar company has to buy it back at market rates. So buying this powerpack and storing energy for commercial purposes is useless. All of the economic discussion above is bunk if the grid needs to buy your excess power. In other words, only greenies would buy it.
One important thing to consider.Â This product makes storing electricity from solar into a break-even cost in any sunny part of the country. Utilities have always hated paying for this. They lose money on it. They've fought legal battles to get it repealed. And now they have the ammunition they need to repeal it, because it's now no longer a burden to consumers to store their excess electricity for later use themselves.
Maybe consider buying utility stocks if you find a company that is over-exposed to paying for home-solar-produced power? I'd tell you to look towards California here.
Inverter Costs
If you don't have solar already, you have to pay for the inverter to make this thing convert DC back to AC for your home. I can't see any reason to do this. The cost differential between peak power and non-peak is about 4-6 cents in most places. Far too little to justify the expense of both an inverter and a powerpack. A gas generator is a better bet if you need reliable power.
Large Scale Efficacy
I'm betting the large-scale systems are more cost-effective. They don't need to be as small and as sleek. And you can have one large inverter for all of the daisy-chained power packs. Who would buy these? Commercial electricity buyers, like stores.
Who wouldn't buy these? Industrial complexes. They make deals directly with electricity companies and pay $0.07 to$0.10 per kwh.
Â - Jason Munster

# Remedying air pollution, one person at a time

One of my friends once told me, "If you are complaining about the government and aren't doing anything to solve the problem, then you are part of the problem."

I decided to do more than write about pollution associated with energy, and have started a side project to build a breathing filter (and mask that it will go with) for people living in and visiting countries with significant air pollution.

My apologies for not posting this sooner, I wanted to wait until I had finished a major milestone on my PhD that was taking literally all of my time. In other words, I didn't want to post about "working on" something that I had no time to work on.Â I hope to become active again in posting related articles now that I've a bit of free time again.

20,000 people die every day from air pollution. Most of them cannot afford current filters. It's time to change that.

So. China and India are not going to institute US-level air pollution controls on their power plants. So if they aren't going to filter the entire sky the way we do, the next best thing is to just filter the parts that people breath. By filtering it just before they breath

"But Jay," you say, "Aren't there other masks on the market already?"

Indeed, my friend, there are. Except most of them fail in one way or another. Nearly all of them fail to achieve a face-seal. This means that there are small leaks. Small leaks are fine when you are filtering large particles like water droplets (think viruses that travel on sneeze particles), because the leaks are often at 90 degree angles. The droplets can't make those 90 degree bends, and they get absorbed by the mask or deposited on the skin. This is why doctors masks can be fairly effective. PM2.5 and chemical pollutants, however, are small. PM2.5 is 1/30th the width of a human hair in diameter. It can easily make a 90 degree turn through a leak in a mask, and get into your lungs where it penetrates deeply, creates scar tissue, and then gives you asthma and lung cancer until it kills you. The other pollutants are literally molecules. They have no problem making any bend of any sort. If there is a leak, they are getting through.

Gas mask. The only true way to ensure there is no leak.

What's the easiest way to tell if your mask leaks? Take a deep, sharp breath. If your mask doesn't push against your face from suction until the pressure equilibrates, you don't have a good seal. So pretty much, every mask short of the one pictures above doesn't work.

So this is one part of what I will address. I've a few methods to ensure no leaks while maintaining low costs for masks. I'm not exactly going to be open on how I will do it, but this is happening.

So, if you plan on traveling in China, India, or near LA (heh) next year and need a breathing filter, be sure to talk to me.

- Jason Munster

# Air quality limits, Geographic Air Pollution Causes

Hi everyone!Â Last weekÂ I wrote about air pollution, where it is bad, what causes it, and the main harmful components of air pollution.This week I am going to give you some exact numbers. First, though, let's start with a scary fact. Then I'm moving into how pollution goes away once it is in the air.

US limits on PM2.5 are 12 micrograms per cubic meter averaged over a year. In Europe, the limit is 25. Note that for every increase of 10 micrograms, there is an associatedÂ 9% increase in lung cancer incidence, and a .6 yearsÂ decrease in life expectancy. Scary, right? China has an annual average limit of 40, and India has an annual average limit of 50. They don't do so well in some cases. Beijing averages 56, and Delhi averages 150. In other words, Delhi's population has somewhere in the vicinity of 10 years less of life from air pollution alone.

What about other pollution? SOx, NOx, and ozone tend to accompany each other. Wherever you have SOx, you have the other two. Even clean-burning natural gas power plants produce NOx, just as a by-product of combustion is our nitrogen atmosphere. NOx becomes ozone and smog when mixed with sunlight and organic radicals (the latter of which exist just about everywhere). In other words, these three things are difficult to separate. Moreover, they are often accompanied by PM2.5. Research is having trouble teasing them apart and figuring out what might cause what. But, again, SOx and NOx become strong acids when they react with the water in your lungs, and ozone is toxic to life at ground level (always remember, ozone 15km overhead blocks out the bad parts of the sun, ozone at ground level damages living things).

SOx and NOx, once emitted, are typically cleared out by rainstorms, creating acid rain. It's better than breathing it in, right?

The US has pretty good air quality overall. But if you look at the US government website that shows current levels of pm2.5, you'll see some cities in the US are straight up awful. While their annual average might be around 20-25, on the day I checked, San Bernardino, CA, had 137 micrograms per cubic meter. This is absurdly high. On days like this, people will have difficulty breathing.

Los Angeles on a polluted day. Thanks Curtis Barnes for the correction!Â Site.

In other words, you can go almost anywhere in the world and find places that are tough to breath in. That being said, there are some countries that are really bad almost everywhere. Bangladesh, India, Nepal, China, and Pakistan are all very polluted. Much of the middle east is as well.

So what makes these things hang out? The most common reasons are inversions. It's when warm air sits on top of colder air. Since air likes to rise when it is warm, if there is a layer of cold air that is polluted that also happens to be capped by warm air, that cold layer will sit there and stagnate. Instead of blowing up or away, it will simply accumulate pollution. Another cause is being surrounded by mountains. Mexico City, for example, is right in the middle of a bunch of mountains. The pollution cannot rise above the mountains, so it lingers and builds. It is also common for coastal areas, or areas next to high deserts, to have times when air refuses to vacate. Those mechanisms are a bit complicated, so we won't discuss them. Finally, being near 30 degrees North or South latitude tends to make air pollution stick around. LA, for example, is at 34 North. The reason for this being bad is that the Earth has the giant airflow patterns. Air is heated at the equator by the sun, then it rises. Eventually it cools and falls near 30 degrees north. The result is that inversions happen more frequently, cause there is air pushing down on the cities.

Diagram of temperature inversion. Site

That's about it for the major causes of air pollution buildup. Of course there has to be pollution to start with for these effects to matter.

Hokay, so, what makes PM2.5 go away when it starts hanging around? Either a wind comes through and blows it out, or a rain comes through. Rain scrubs PM2.5 by absorbing it, and it chemically converts SOx and NOx to acids that become solutes in the rain. Hence acid rain. Also hence why skies are most clear after rains, and how they can smell so fresh and clean after rain. So, if you are going to go for a run in Beijing or Delhi, wait til after a big rainstorm ðŸ™‚

Let's talk about that last point a little bit more. China is dry nearly all the time. It doesn't rain much there, so it has a bigger problem of building up air pollution. India has the monsoon season, but is also fairly dry otherwise. What about LA? If you have ever driven in a slight rainstorm in LA, you will see that everyone freaks out and has no clue how to drive in the rain. It's hilarious for about 5 seconds until you realize you are now in a traffic jam. It doesn't rain there, either.

So. Your most polluted places will be near 30 degrees latitude, potentially on the coast or in mountains, dry, and in the vicinity of polluting vehicles, industry, or power plants. Neat. right? I bet you thought it was just pollution alone that caused pollution to linger.

Hokay, that's all for now. Thanks for reading!

- Jason Munster

# Which Country has the Worst Air Pollution in the World?

Before I get into anything, this is a first in a series of three articles I am going to be releasing. Instead of my monthly release rate, I am going to be releasing them one each week. If you are traveling to or live in a polluted environment, I highly suggest you subscribe to the blog or do it as an RSS feed.

Now to the article!

If you guessed China, you guessed wrong. Did you get it wrong? If you say you didn't, I am going to call you a liar. Every person I know, when asked which country in the world has the worst air pollution, answered China. This includes experts on China, experts on air pollution, and experts on countries that are more polluted than china.

Also, the number of people that die per year from air pollution is staggering, more on that after the math.

China isn't even close to being the country with the most fouled air. That distinction belongs to India, by a huge margin.

Okay, well, let's delve further into it. Of the top 20 most polluted cities in the world, how many would you guess are in China? Okay, that was a trick question. China doesn't have any of the top 20 most polluted cities in the world. And India holds the distinction of having at least 10 of them.

A gate in India that can't be seen through air pollution.

Before getting to the science grit, one more important thing. Owing entirely to city air pollution in India, at least one study shows that Indian citizens living in cities have 30% less lung capacity than Europeans living in cities. So, pretty much, pollution makes it so

Okay, let's back up and discuss air pollution a bit.

What is Air Pollution? (This is the technical part of the post)

In this above mentioned study, air pollution is strictly PM2.5. Why is that? Because PM2.5 is particulates smaller than 2.5 microns, roughly 1/30th the width of human hair. They are small enough that they penetrate deep into the lungs, where they cause permanent damage and can lead to cancer. PM2.5 is produced by powerplants (mostly coal-fired) and any combustion-based motor vehicle. The EPA has a great guideline for PM2.5 if you want to read more.

There are other pollutants that everyone seems to ignore. Back in the day, you heard a lot about acid rain. Acid rain is caused by $SO_2$ and $NO_2$ . CombustingÂ anything creates NO, cause there is so much $N_2$ in the air (78% of the stuff we breath is $N_2$ ) that some of it combines with oxygen during combustion, creating NO. NO reacts with $O_2$ to produce NO2 and O-, the latter of which produces ground-level ozone (more on that soon). Let's look at what happens to $SO_2$ and $NO_2$ in air:

$2SO_2 + 2H_2O + O_2 \rightarrow 2H_2SO_4$

So that's sulphuric acid.

$2NO_2 + H_2O \rightarrow HNO_2 + HNO_3$

And that is nitrous and nitric acid. Another fun reaction is:

$NO + VOC + sunlight \rightarrow O_3$

VOCs are Volatile Organic Carbons. It pretty much means organic matter in the air. It comes from plants. $O_3$ , or ozone, is bad for people and plants at ground level.

So let's review what happens here. Power plants burn fossil fuels, they produce PM2.5 which causes cancer, coal-fired powerplants produce $SO_2$ which becomes acid in your lungs, and all combustion plants produce $NO_2$ which also becomes acid in your lungs. PM2.5 is the worst, but the other pollutants are also bad. Burning coal causes the most of all of these pollutants. Lower grade coal, the stuff burned more often in China and India (the US has high grade coal), has less energy relative to pollutants, so it makes more pollution.

Now, exactly how bad are ozone, NOx ( $NO_2$ ) and SOx ( $SO_2$ )? They are all similar, so lets just look at SOx health effects according to the EPA. In short, exercising in an environment with this stuff is bad for you, and sends people to the emergency room. In the worst case scenario, it exacerbates or triggers asthma, heart attacks, and aneurysms, killing people nearly instantly. Long term exposure increases asthma and other health hazards. Now keep in mind that this stuff is considered less of a problem than PM2.5.

Back to the Qualitative

Okay, now that we know what the stuff is and what it does, let's get to some specific numbers. The World Health Organization indicates that air pollution is "single biggest environmental health risk in the world" the largest health hazard in the world, killing 7 million people per year.

What's the best way to deal with this stuff? Staying indoors helps a lot. Your house acts as a good barrier against it. Having a filter also helps. If you live in China or India, build one of these at your home. The filter will stop working eventually, so it will have replacement costs, but you can probably get clean air for around $100 per year for a single room in your house. Now keep in mind, this is a HEPA filter, which filters out only particles. Good luck with that SOx, NOx, and ozone. The guy who stapled together the filter and the fan states that it's the only thing you need for clean air in his blog. Clearly the PhD he is learning in psychologyÂ does not qualify him to know a lot about air quality. It doesn't disqualify him from knowing about it, but being completely unaware of the chemicals I described above does. HEPA + fan. Good for PM2.5, useless vs. ozone, SOx, and NOx. In other words, this filter will work inside, but you are still going to get bad chemicals living in your lungs. If you want to filter more, be prepared to shell out thousands of USD. Also, if you plan on going outside, or you want to exercise, if you work outside, you're pretty well screwed. There are a few masks that work, but all have their flaws or are expensive. More on this later, we've hit 1000 words and it's time to go. Before we let me repeat one thing. If you are in a polluted area: Do. Not. Exercise. Anywhere. That. Isn't. Filtered. And no mask on the market filters out SOx, NOx, and Ozone. Thanks for reading! - Jason Munster # Solar Roadways: Full of Crap and Bad at Math First of all, sorry it has been over a month since I've posted. I've decided to get together a few people to start addressing some of the things I write about, and that has taken my time up til now. I'll be posting once per month from here on out, on the first SundayÂ of every month. Today's post isÂ a long one, but one of the most interesting I've written by far. This is the one time where I will say the following: if you are short of time, skip directly to the math section. It shows a serious glaring deficiency of either forethought or disclosure on the part of the founders of Solar Roadways. Moreover, it shows they can't do basic math. Never trust an engineer who can't do basic math. It's a very crackpot idea. Here We Go! I've heard a lot of talk about Solar RoadwaysÂ recently. I'm going to use it as an example of how to analyze some "science." After you follow the very basic math below, you will see that the team at Solar Roadways does not know what numbers to run*. A much larger problem: they suggest that solar roadsÂ can replace fossil fuel power, while simultaneously and surreptitiously admitting that they need a ton of grid power to make this work. So pretty much they are either dumb or straight up liars. First, let's talk about why these roadsÂ might be good, from their point of view. Being a by-the-numbers type of guy, the first thing I did was check the "numbers" section of their website. While their assumptions are dubious at best (more on that later) TheyÂ say that their roads could provide 3x the energy that the US needs, in kilowatt hours (kWh is a useless measurement here, cause it will be intermittent power. In other words, it produces no energy at night, and will need to be supplemented by fossil fuel power. More on that later). Also, the roads look a lot cooler, with light-up sections, and ability to melt snow so that road maintenance is reduced. So the thing is wired to the grid so that if it snows, it can use heating elements to melt the snow instead of plowing it. But doesn't snow take a lot of energy to melt? Would it take less energy just to push it with a plow? Time for the math! Math of Melting vs Pushing Snow Plow trucks to be replaced by Solar Roads? Not happening. Okay. Let's assume middle-case scenario of 8 inches of snowfall, being removed with one sweep by plow trucks, and that this is between powder and heavy snow in consistency, which means 1" of water equivalent. A DOT snowplow clears 10' width of snow, or 120 inches. In one foot of movement forward and plowing 8" of snow it moves the water-weight of 1"x120"x12" or $1 \cdot 120 \cdot 12 = 1440 in^3$ Now we have to figure out how much energy cost this took in fuel, so we will later relate this to the mileage efficiency of a DOT truck. First, let's figure out how much energy it takes to melt this much snow into water. Do do this we need the latent heat of fusion, or the energy it takes to transition from ice to snow. It's 334 Joules/gram. How do we convert from cubic inches of water to grams? Easy. Because the metric system makes sense, one $cm^3$ of water = 1 gram. There are 2.54 cm per inch, so: $1440 in^3 * (2.54 cm/in)^3 = 23600g$ Okay, we have grams, now let's calculate the energy to melt as much snow as a plow moves from driving 1': $23600 g \cdot 334 \frac{J}{g} = 7,880,000 J$ Or ~7.8MJ. Per foot. Or, for a mile: $7.8 \frac{MJ}{ft} \cdot 5280 \frac{ft}{mile} = 41184MJ/mile$ to melt 8 inches of snow. Okay, so, a plowtruck uses diesel. Each gallon of diesel has 136.6MJ. Very conservatively assuming a plowtruck gets ~5 miles to a gallon (I'm guessing it's more like 10, someone who has driven one, correct me and I will correct these #'s), it would take 27.3 MJ to plow one mile of snow. Compared to 41,184MJ to melt it. It literally takes 1500x as much energy to melt is as it would to move it. This is what you would call a very very bad idea.Â Engineers as cofounders should know better than to let this slide as a potential solution. End of Math Section Okay, so now that we've completely dismantled the case of using these things to melt snow, lets move on to some other issues. We'll skip theÂ minor issues, because that's just nitpicking, and move straight to the parts where they just don't know what they are talking about, and finish with things they clearly know about, but are purposefully misleading people with in order to get more money. Finally, we will close with me realizing that Nathan Fillion is a fool. Okay, to the problems with this solar roadways project: Dubious assumptions: Things they don't understand: the supply lines of a very basic input. REE mining in China is not a clean thing. Nor was it great in the US. Right now there is not enough world production to make enough of these solar roadway tiles. Look at this article to see more pictures of REE production in China. They assume an 18.5% efficiency of the solar panels. These are panels that use Rare Earth Elements (REEs). On their FAQ, when someone asks if they are using REEs, they state (paraphrased), "Our electronics don't use silver or gold" (neither of which are REEs,Â so they are either changing the topic or don't know what question they are answering) "but we can use any solar cell." Good that they can use any solar cell, because there is not enough REE production in the world to produce solar at the scale they need to even replace one major highway with these. Bad they they use 18.5% as their assumed efficiency, because solar cells in this range of efficiency use REEs. REEs are pretty much only produced in China, because producing themÂ make a massive amount of pollution. Decades ago every other major country quit producing REEs because of the pollution they cause, and because China didn't care about pollution or health hazards, so the world was happy to let them pollute themselves and take their REEs. It's been so long since the US produced REEsÂ that we literally don't know how. Solar Roadway's answer is "let's leave this to the government." They aren't addressing the problem at all. While other countries are looking to have their own production, it will take a very long time for this to come to fruition, and the production rate still won't be enough for a second-rate harvesting design (flat roads with bad optics vs. tilted panels with great optics to concentrate light perfectly). At best, they can go with non-REE solar cells, which have about an 5-10% efficiency. That means that each of their hexagonal panels will produce half the power anticipated, and thus will make half as much money toward recuperating their costs. In other words, these non-REE solar panels need more basic raw materials (in terms of roadway) per kwh produced, and thus will cost more per unit energy, in an already material-intensive design for a solar cell. This shows that the project is lacking in any real expertise or understanding of the core problem they are trying to solve. Keep in mind that these are not dealbreakers. The team could hire an expert, or consulting, to fill in their knowledge gaps (likely the former, consultants are expensive, and they really need long-term help to bring this to fruition). Also, it doesn't negate all the other benefits of the solar roadways. Finally, non-REE solar panels are a hot topic in research. If the rest of the solar roadways tech is developed, and they are just waiting for good solar cells, it will rapidly enhance future deployment. In short, the solar cells are a slight additional benefit to whatever holds them in this case of mass-distribution and inefficient use of cells. So if this new road itself doesn't compare favorably to asphalt, the project is sunk in the water. Things they are just completely wrong/misleading about: melting snow, shutdown of fossil fuel, price of energy We discussed the melting of snow. They suggest it replace snowplows. Bad idea. It's clearly not going to work, energetically speaking. They keep talking about how 50% of US electricity use is from fossil fuels, and how these roads are going to replace it. This is so wrong that it is hard to debunk in one post. But here goes: First, only 40% of US primary energyÂ (my link, please read it for background if you feel a bit lost, it is far briefer than this post)Â is for electricity. Second, only 66% electricity of this comes from fossil fuels. In other words, 26.4% of US electricity comes from fossil fuels (if we change all our transportation over to electric, these numbers will change, but that would require these roads to have induction power installed - AKA roads that provide the car with energy for driving so they don't have range issues). This is the total amount of emissions that could be replaced by solar roads in their current design. Primary energy in the US. As detailed by the math above, only 25% of primary energy in the US can currently be replaced. So, pretty much they are off to a bad/misleading start there. But this is nitpicking. The real issue comes in when they talk about replacing fossil fuels. First, they talk about heating the roads. This means they will have to put energy into the roads. Where will this energy come from? Power plants. So much for shutting down fossil fuel. But wait, there's more! Solar power is intermittent. It doesn't even work at night, so power plants also have to be on then. So pretty much, their idea of shutting down power plants is completely shot out of the water by these two things. Can solar roadways still be part of a larger energy solution? Well, not if they are heating roads to melt snow. That just takes far too much energy. If they scrap the melting snow idea and go to just producing energy? Yeah, it might help some. But let's get to one last funny part, the one that shows they know that they won't be shutting down fossil fuel power any time soon. Energy storage. From their FAQ, they mention that there will be "virtual storage" in that during the day they will add power to the grid, and at night they will take power from the grid. This is double-speak to mean: during the day we will provide power that can offset coal and natural gas power plants. At night when we aren't producing, natural gas powerplantsÂ (again, my link) will fire up to power our roads (nuclear is not an option for power phasing like this, nuclear powerplants don't spin up or wind down on half-day timescales). In other words, they fully well understand that they aren't going to do away with the rest of the power grid, and that they aren't going to replace all those fossil fuel emissions. So pretty much, saying that these can replace our power grid is double-speak sales points. The final problem? They don't understand energy distribution. Electricity is produced at about$0.03 to $0.08 per kwh at a power plant. By the time it arrives to us, we pay$0.13 to $0.25 (or$0.50 in Hawaii), because distribution costs a lot of money. Solar panels on our roofs produce power that costs about $0.15 to$0.20 cents per kwh, give or take. So the end-user cost of grid power is the same as that of house solar. But if you run that solar power through the distribution channels and add that price, suddenly you're talking $0.25 to$0.40 power. So, unless they are giving this power away for free, it's probably not gonna be a great solution.

Some Solutions

I've softened my usual tone quite a bit for this writeup, cause I don't want to be a complete naysayer of something who is trying to do something positive (sorry, I know how much you all know and love my biting sarcasm and scathing reviews).Outside of their false solution of trying to solve the energy/climate issue, this idea has some potential. On that note, rather than pointing out problems, I've come up with some great solutions.

My suggestions:

1: Nix the whole melting of snow concept to replace plow trucks. Energetically, it doesn't work. Plow trucks should still exist. Instead of replacing them, replace the salt and sand they need to spread. Make it so plowtrucks plow all but the last 1/8" of snow, then melt thatÂ (note, this is still a tremendous amount of energy, but stay with me). This will have a few benefits:

• No more salt and sand on roads means less salt and sand damage to vehicles, making vehicles last longer
• No more salt and sand on roads means that DOTs can save money buy not buying these things
• ... no salt and sand runoff, which pollutes local waterways
• ... animals that go to roadways in the spring to lick off accumulated salt won't do that, reducing traffic accidents from moose and deer, etc.

2: Get a bit more cognizant or REEs and their limitations. Don't use bad assumptions that are easy to poke holes in.

3: Stop selling people on false promises of doing away with fossil fuels. It makes the whole green movement look bad when prominent people are lying or severely misinformed.

4: Focus on the real potential of making these have inductive energy for electric cars. This could eliminate range anxiety (people fearing their electric cars will run out of energy and leave them stranded). Electric car sales will move a lot faster if people can drive from LA to SF, or between Boston/NYC/DC. The potential partnerships include every major car company that markets in the US. Also, this could reduce oil use, and drastically reduce air pollution from cars in these busy areas by further replacing combustion engines with electric ones (even if we power them with electricity from coal, a well-scrubbed coal plant produces fewer bad things than a car). Moreover, since people won't need fuel, they could be assessed a charge per mile driven instead. By whoever owns the roads. Here is your real money-maker for the roads, fellas. It will be far more lucrative than producing tiny amounts of electricity. Please get on this. It will lead to more electric car research, and more rapidly drive forward battery development, and it turns out that cars make a bunch of really bad pollution that causes harmful side effects like death.

This last bit, changing your startup's tack when a better model comes along, is important. And solar roadways needs to do that for a viable product, because their core solution faces a lot of headwinds (yay, sailing puns!) in break-even with their current model.

So, overall, these roads could be an excellent idea. The solar part, their main selling point, is BS because of cost, efficacy, and the need for gas-fired power plants to supplement them. The shutting down most fossil power plants is a lot of nonsense for the same reason. Making the environment better by reducing salt and sand use? Decent. Potentially by making most cars electric? Game-changer, but they are barely looking at that aspect right now. Probably cause they are too busy counting the piles of cash that indiegogo just threw at them (or, more likely, answering the insane number of emails that comes from this sort of campaign).

Hokay, that's my piece. Thanks for reading this long one.

- Jason Munster

Extra stuff!

Some background about Solar Roadways initial funding: They were funded by government SBIR. This stands for Small Business Innovative Research. It's for high-risk, high-reward research. In other words, this was considered high-risk from the start. They got a phase II, which means they did well. It's clear they still have issues and are still high-risk. But I'm glad someone is paying for research and innovation like this, especially because if it pays off, it could result in more jobs and more taxpayer base. That being said, they haven't received more funding or any grants to build this out further. Possibly cause it's a big, crazy idea. Elon Musk can pull off big, crazy ideas, because he is a brilliant manager and has a very strong personality. These guys are going to need some bigger guns on their team if they are going to make something of this project.

Second, Nathan Fillion is a bit of a fool. In touting Solar Roadways, he displays why pop culture heroes shouldn't get involved in matters outside their field of expertise (mainly, looking good in front of a camera, and pretending to be someone who they aren't in front of a camera). His adoration of something he doesn't understand falls deep within the territory of religious fervor. Nerds: just cause one of your heroes likes something doesn't mean it actually is plausible.

One final-final note: I know that this post is 3x longer than my rest. I assure you, it's far shorter than I wanted it to be. I don't believe in two-part posts very often, though. If you have read this far. please leave a comment so I can appreciate you forever ðŸ™‚

*Engineers who don't know what numbers to run are a bad investment. For my own company, all business types are skeptical of how much I know (or want to take advantage of me fully) until they find out that I used to be in finance and have a really good idea of the big picture of most things. In short, this company has a lot of potential once they take on broader experts.