Mobile Air Monitoring with AirCasting


We have all smelled it: smoke from burning wood. Whether it’s from wildfires, campfires, or fireplaces, trillions of tiny particles float into the air when wood burns. In my neighborhood in northern California, most of the particle pollution in the wintertime originates from my neighbors’ burning wood in their fireplaces not for warmth, but for aesthetic reasons.

It matters because when particles are inhaled, they cause health problems ranging from asthma to heart attacks. And if you think your chimney sends the particle up, up, and away from your house, you’re wrong. A study (Pierson et al., 1989) showed that 70% of the particle pollution that goes up the chimney re-enters your home or impacts your neighbors. So you’re just polluting yourself.

While I don’t want to out people in my neighborhood for burning wood, my geeky, let’s-measure-everything curiosity got the best of me. So I decided to set up a mobile wood smoke monitoring system in my car. I mostly wanted to see if I could detect which streets were more polluted. So, armed with a decent (yet expensive) particle measuring instrument, an Arduino, software, and two spare weekends, I created a system that worked quite well. This post will briefly describe the system and present the results.

carsetup1 carsetup2

I chose to use a mid-cost ($5,000) particle measurement device and a bunch of DIY items. This helped ensure particle measurements of sufficient quality to draw conclusions from, yet provided a system where lower-cost particle sensors could replace the expensive instrument someday. The setup consisted of:

  • Nephelometer for measuring particles and estimating PM2.5 (particulate matter of 2.5 micrometers or less in size). This unit, manufactured by Thermo Scientific, uses a pump to draw air into a chamber, where particles scatter light into a photo detector. The light scattering is proportional to the amount or mass of particles in the air.
  • Cyclone inlet that spins the air to remove the larger particles and creates an airflow with only the smaller, unhealthy particles (less than 2.5 micrometers).
  • Copper tubing that guides the inflow air from the Cyclone inlet to the Nephelometer.
  • DTH temperature and humidity sensor mounted outside on the copper tubing. Measuring humidity was important because during moist conditions (>85%), water condenses onto particles and falsely causes more light scattering, and thus higher PM2.5 measurement.
  • AirCasting, an open-source platform for recording, mapping, and sharing health and environmental data using your smartphone.

The Arduino received inputs from the nephelometer and the temperature and humidity sensors. Measurements were averaged every second and sent, via Bluetooth, to the AirCasting app running on my Android phone. The real-time data streamed into the app’s screen, which helped me confirm the smoky and clean streets in my neighborhood in real time, while I was driving around.   When I finished driving the route, I saved the measurement session with all its data and uploaded it to the website. I’ve driven hundreds of miles in northern California with this measurement system. On one night, November 10, 2013, I repeatedly drove a route in my neighborhood.

The data showed lots of interesting things (as shown in the figures below). Conditions in the afternoon (1400 PST) showed good air quality levels throughout the neighborhood — no burning yet. By early evening (1800 PST), one residential area right next to Santa Rosa’s major hospital showed very high PM2.5 levels from wood burning. In fact the PM levels were over 150 ug/m3, which is Very Unhealthy on EPA’s air quality index. This is approaching levels that you would commonly see in polluted cities like Beijing. It’s remarkable how localized the smoke can remain. Notice that on one street the air quality levels are healthy (or Good), whereas on Parker Drive the air is Very Unhealthy.

day earlyevening lateevening

By 1900 PST, the wood burning continued at homes near the hospital. Air quality on other streets was at Moderate levels due to isolated burning and due to a weather condition called a temperature inversion. The temperature inversion acts like a lid on the atmosphere and traps pollution (in this case smoke) near the ground. By 2000 PST, light and variable winds slowly dispersed the smoke near the hospital hundreds of feet to the southeast. One hour later, at 2100 PST, the air quality levels were Moderate throughout the area, and the hot spot near the hospital had dispersed. But the particles just didn’t disappear; while no longer concentrated and unhealthy, the particles were just pushed to some other neighborhood by the slow and gentle overnight winds.

Post script: I haven’t ratted out my neighbors, but I have let some of them know that we are only polluting ourselves.


Pierson W.E., Koenig J.Q., and Bardana E.J. (1989) Potential adverse health effects of wood smoke. The Western Journal of Medicine, 151(3), 339-342, September. Available at


Makers Against Ebola – Pull Tabs

Pull Tabs as a Solution for Easier Disrobing

Pull tabs as a solution for easier disrobing

Contamination; mixing the bad with the good. In this case, getting Ebola virus on yourself. As a worker takes off protective clothing is when they’re most likely to get exposed. Every effort to make the awkward disrobing process easier is a step in the direction of increased safety. Turns out that tabs are a great feature for making this happen.

One source of maker innovation comes from applying the ideas of one discipline to another. In this case, looking into wet suit design provided insight for improving PPE suits. Everybody knows that removing a back-entry wet suit starts with pulling down a zipper with a long strap attached. Why not do the same with PPE and add straps to back-entry suits? Also, to have the greatest impact on the current Ebola epidemic it would be cheaper and speedier to apply retrofits to existing equipment.

So where could tabs or straps be added to a PPE to make removal easier and safer? Under the leadership of Nicole Daphne Tricoukes, a team which included Kailey Shara and Brian Russell set out to answer that question. The results were three distinct sets of tabs which could be added to existing suits which enhance safety while disrobing.

Collar tabs used in a peeling action to safely remove back-entry PPE suit

Collar tabs used in a peeling action to safely remove back-entry PPE suit

First, to peel off a back-entry PPE suit requires a bit of physical gymnastic and if you’re trying to avoid contamination this isn’t a good thing. Ideally clean hands would only touch the clean interior of the suit to pull and remove it. Problem is, there’s nothing to grasp normally. However, by adding tabs inside the collar flaps you provide a gripping point to pull and peel. This is a cheap retrofit solution that can be added to existing suits.

Cuff tabs to ease pant legs over boots

Cuff tabs to ease pant legs over boots

Second, if you watched the PPE disrobing video you’ll know that getting the pant legs off over the boots is a clumsy process. It’s just plain hard to get the cuff over the heal to begin slipping the boot up through the pant leg. What if a tab was sewn at the base of the leg? As you see above, the other foot could step on the tab thereby securing the cuff and allowing the boot to be pulled out of the suit in a much less clumsy and therefore less unsafe manner. Again, an inexpensive retrofit to existing PPE inventory.

Zipper tabs used to make unzipping easy and safe

Zipper tabs used to make unzipping easy and safe

Third, while the tab extenders made grasping the zipper easier, the use of long straps makes unzipping simpler as shown at the top. One strap is attached to the PPE collar while another is attached to the zipper tab extender. The first strap secures the collar while the second strap pulls to unzip the PPE. Opening the suit safely is a critical first step to releasing body heat build-up and beginning the recovery period. Best of all? This is again a cheap retrofit.

The design guidelines for this project call for low-cost, easy to produce, quick to deploy, and impactful solutions. These uses of add-on tabs are wonderful examples of this.

Perhaps in reading this you saw a way to improve it? Maybe you’d like to learn more about this solution? If so then come on over to the project on OpenIEDO and join in. Makers are welcome! #FightingEbola

Makers Against Ebola – Design Goals

Healthcare Workers Fighting Ebola on the Front Line (photo from US AID)

Healthcare Workers Fighting Ebola on the Front Line (photo from US AID)

The Fighting Ebola Challenge has hit its halfway mark. Ideas have poured in from around the world with over 700 people collaborating on solutions to help healthcare workers on the front lines. Makers are jumping on board.

Some reminders about Challenge design goals from the OpenIDO team:

First, ideas should have the potential for significant impact within a short time frame – we want to get ideas to the field in a matter of months! Second, ideas should be low cost and easy to produce. And third, ideas should be simple to deploy and adopt – keep in mind the infrastructure limitations as well as our human center design principles. Do you have an idea that’s ready for the world?

Get prepped with background on the virus, personal protective equipment and the challenges of PPE suits. Then, jump over to the OpenIDEO overview of the Fighting Ebola Challenge and get started. Ebola is wrecking havoc on thousands of peoples’ live. Many are dying and many more are in jeopardy.

Creative makers can solve problems; we can help in the fight against Ebola.

Makers Against Ebola – Zipper Extenders

Evolutions of a Zipper Pull Tab Extender

Evolutions of a Zipper Pull Tab Extender

Exhausted from heat inside a protective suit and burdened with layers of gloves, to disrobe you need to grasp and pull a tiny zipper tab. Who needs this challenge!? Not only would this be frustrating but it could be dangerous. Lack of dexterity and coordination can cause exposure to infection. One solution proposed at Fighting Ebola was to design an enlarged, clip-on zipper tab.

Thermal Image of Retained Heat After Just One Hour

Thermal Image of Retained Heat After Just One Hour

Remember, working inside a PPE suit in West African is exhausting. Body heat builds up. You sweat profusely. Judgment becomes impaired and coordination is affected after just 40 to 60 minutes. Caution is needed to avoid exposure to Ebola so these conditions represent risk. To address this, Brian Russell decided that making the PPE’s zipper tab larger would facilitate safe disrobing and he developed it as part of this larger project.

Understand that the Fighting Ebola Grand Challenge is to provide relief ASAP to caregivers on the front lines of the Ebola crisis. We’re looking for solutions NOW, not in 12 months, so Brian needed to develop a tab-extender that would work with existing PPE suits. He needed to make existing zipper tabs larger to make current suits easier to remove.

First Prototype of Pull Tab Extender

First Prototype of Pull Tab Extender

My favorite insight of Brian’s was that the zipper tabs have a hole at the tip. This was key to figuring out how to connect the new tab sleeve to the existing zipper. He determined that by printing a sufficiently large dimple in the right place within the sleeve the tab extender would “click” into place and hold. This meant tab extenders could be used on the existing inventory of PPE suits. Brilliant!

First Prototype in Use

First Prototype in Use

Sitting down with calipers Brian measured the tab and started modeling in Autodesk Inventor. Through a series of prototypes, trial and error, and input from experts he worked through the variety of prototypes you see above.

Key input came from the head of training for Médecins Sans Frontières (Doctors Without Borders) in Africa. The hole needed to be a certain size for gripping with gloves but not too big within the overlapping folds of the suit. Sharp corners had to be avoided because they could open wounds thereby risking infection from Ebola. These insights can only come from subject matter experts and they are available at the project’s OpenIDEO site to provide feedback to YOU on YOUR ideas.

Final Prototype in Use

Final Prototype in Use

This zipper extender is the type of maker project that can help save lives. It takes effort to learn about Ebola and about working in PPE suits but with this knowledge you too can help fight the battle. Come see what others have proposed, submit your own ideas, or contribute to others’ submissions. This is a collaborative effort.

Makers can help; are you one of them?

Makers Against Ebola – Training Videos

Ebola Training Videos from Catherine Bachy

Ebola Training Videos from Catherine Bachy

Between the caregiver and the Ebola virus is protective clothing. Dressing and undressing correctly are essential for safety. These training videos instruct workers on how to do both correctly. Worn right it protects; worn wrong it infects.

Let’s remember the context. Infection comes from contacting the virus and transferring it to your system. Being careless or not following the steps in these videos puts a care worker at risk.

Also, remember these folks in West Africa are working in high heat and humidity. Due to the risk of heat exhaustion they’re allowed to work only 40 – 60 minutes per shift. That means they dress and undress within one hour, will take a break, and then go through the whole routine again!

This series on is meant to inform and enlist you, the maker, in the fight against Ebola. In coming posts we’ll be featuring maker-solutions being matured over on Fighting Ebola. Stay tuned and if you want to stay current on developments then follow #FightingEbola.

Join the fight!

Makers Against Ebola – Personal Protection Equipment

A Demonstration on Suiting-up in a PPE

A Demonstration on Suiting-up in a PPE

Since contracting Ebola can only happen when people come in contact with infected fluids, caregivers need to be protected. Personal Protection Equipment (PPE) are actually the solution but current PPE come with drawbacks. Improving PPE is a major goal of Fighting Ebola and it’s one area where makers can have an impact. What follows is an introduction to PPE because we can’t improve them if we don’t understand them.

Hood, googles, mask of a PPE.

Hood, googles, mask of a PPE.

PPE as pictured above is a series of layers put on in a specified order. The first layer is body cloth cover, followed by Tyvek, followed by Tychem where each progressive layer breathes less, is less permeable. Layers of gloves are also put on in a specific sequence. Lastly, to protect the mucus membranes located in the eyes, nose and mouth healthcare workers dawn head covers such as hoods, duckbill masks and goggles. Getting the sequence right is important to being protected; even more important is taking the PPE off properly as that’s when a slip-up poses the risk of infection.

Photo by Ted Eytan

Photo by Ted Eytan

At this point caregivers are dressed and ready to work so what do they do in this getup? In an Ebola Care Unit (ECU) they provide care to the sick. This means monitoring patients’ conditions, examining them and doing procedures like drawing blood. Patients often need assistance eating, drinking and taking their medicine. Caregivers will also clean the sick and provide emotional support. Remember, they’re doing all this from inside this layered getup, in close proximity to the virus, and with the utmost need to be careful while at the same time being helpful.

Ebola patients in the ECU are not in good physical condition. They’re weak and need help walking or they need to be carried. They produce lots of fluids such as vomit and diarrhea which are filled with Ebola virus. Patients are understandably restless, depressed and anxious. Having to deliver care is difficult enough but these factors complicate matters.

A care giver’s life inside the PPE is not pleasant. By design the suit doesn’t allow for much ventilation so as you generate heat the temperature in the PPE goes up. In an air conditioned room a person would get hot; in the warmth of West Africa they quickly overheat and dehydrate as their body sweats in an effort to cool itself. In addition to heat there are issues with how their senses are impaired. You might have goggles on which are probably fogged and their peripheral vision is restricted. Their head is covered so their face is hidden, their voice is muffled, their hearing and situational awareness are impaired. It’s suffocating, requires constant vigilance and restraint of habits to not become infected, and there’s a feeling of physical and emotional isolation. These introduce serious challenges to effective care delivery!

Only 40-60 minutes of work time.

Only 40-60 minutes of work time.

Conditions in this gear are so bad that there are serious impacts on scheduling care givers. A worker can only realistically withstand conditions for 40 – 60 minutes inside a Tychem-C PPE before needing to disrobe. With such short windows of uptime there’s pressure to optimize how care time is spent. Physical and psychological conditions in the suit are such that there’s a required recuperation period before suiting up again. Resource planning is greatly complicated by this cycle of downtime to recovery. Planning must be done by the man hour of labor. In the context of too few healthcare workers and a rapidly growing epidemic the PPE issues become a real challenge.

Oh and what’s the per unit cost for this outfit? The Ebola outfit at the top of this post is roughly $60 and, again, it’s almost all thrown away after one hour. Seems to me there’s lots of opportunity for makers to improve on this situation!

Makers Against Ebola – The Missions

The Four Missions (photos from

The Four Missions (photos from

How are makers supposed to contribute to Fighting Ebola: A Grand Challenge for Development? This high-urgency initiative against Ebola is focused around four missions. They’re not centered around medical science but around the healthcare worker, their ability to provide care and stop the spread of the disease.

As you’ll see, these are areas where we makers can help.

Mission #1Strengthen Healthcare Capacity The wonderful care givers on the frontline must be further empowered and protected. Their Personal Protective Equipment (PPE) is cumbersome, hot, and uncomfortable which result in short work shifts, clumsy movement and potential exposure to Ebola. Their work environment and tools must be improved to provide better, safer care. This mission is ripe for maker innovation.

Mission #2Promote Care-Seeking Understandably there is fear of Ebola and in many instances aversion to seeking care. Help is needed to change behavior and encourage care-seeking, it’s key to stemming the epidemic. This is an area where creative makers can contribute to the pool of ideas.

Mission #3Boost Tracking & Communication Measuring, gathering and analyzing data are second nature to makers and can help with decision making, resource deployment, and containment strategies. With all we do with micro controllers, sensors, actuators and communications this is a natural area for us to offer help.

Mission #4Surprise Us! As with any good solution-seeking endeavor it’s open ended. Our community spends its time outside the box more than most so as we learn more we’re likely to have other helpful ideas. This mission is where ideas that don’t fit above will be captured. It’s a place where many makers will likely make contributions.

Solving problems, that’s the kind of thing we’re really good at. Now is our chance to help stem a crisis which poses increasing threat. Let’s show the world what makers can do; go now and start contributing ideas.

Makers Against Ebola – The Virus

Ebola Medical Ward (by Daniel Bausch, MD, MPH&TM)

Ebola Medical Ward (photo by Daniel Bausch, MD, MPH&TM)

Why are so many people getting sick if Ebola is not very contagious? How are makers supposed to get involved and make a difference? We need to understand fundamentals about Ebola if we’re going to help with Fighting Ebola. Let’s start with a little background on the disease.

The current epidemic is the Zaire strain of Ebola. People become infected with it only when they come in contact with bodily fluids (e.g. blood, saliva, tears, urine, etc.) of someone showing symptoms. Ebola is not airborne. To become infected you must transfer the virus from infected fluids in to your system. The common pathways are through the mucus membranes of the eyes, nose and mouth but there are other ways such as through an open wound. This need for direct contact is why it’s not very contagious.

However, in caring for the sick there is plenty of opportunity to contract the disease. Infected people experience fever, headache, nausea, vomiting, diarrhea and more producing lots of infected fluids. The sicker the infected, the more virus they produce, and the easier it is for someone to pick it up. Very importantly, you must come in physical contact with body fluids and the virus must find its way into your system. The virus is found in a variety of fluids including blood, saliva, stools, tears, urine, sweat, breast milk, and semen. Caring for the sick puts people in close proximity to infected fluids and potentially exposing caregivers to Ebola.

Another irony is that while it’s often deadly if you contract it, the Ebola virus is actually quite easy to kill. This virus is in what’s called a “lipid envelope”, that means the virus is enclosed in a vulnerable fatty enclosure. The protective envelop can be easily destroyed with exposure to disinfectants, heat or UV light from sunshine. The virus only stays alive for hours to days and is easy to kill with bleach or alcohol. In many ways this makes the virus seem rather feeble and easy to clean up after.

So, Ebola is not very contagious. However the sick produce lots of fluids and contact with those can lead to infection.

Therein lies our challenge … eliminating exposure while close to the infected. We makers can invent ways to do this, prototype our ideas, and help shut down this crisis. Pop on over to the Research area of the Challenge to learn more. To solve a problem you must first understand it.

Makers Against Ebola – Intro

Colorized Ebola Virus (by Cynthia Goldsmith)

Colorized Ebola Virus (by Cynthia Goldsmith)

While not highly contagious, Ebola is highly deadly once contracted. An estimated 70% of people who get sick with Ebola will die. The current outbreak began in West Africa back in March of 2014 and has since spread through Sierra Leone, Liberia and Guinea. As of October 10 the CDC reports there were 8376 cases resulting in 4024 deaths so far. Again, while not highly contagious, it is spreading and the numbers of sick and dying are growing.

So how can makers help to fight Ebola?

We can help by doing what we do best: solving problems.

Fighting Ebola: A Grand Challenge for Development is a high-urgency initiative to help healthcare workers at the front lines provide better care and stop the spread of Ebola. The program is made up of two parts: 1) OpenIDEO (an open innovation platform) and 2) the Challenge Grant (a funding platform). The Challenge is a fast-paced effort to make a difference quickly.

OpenIDEO is a natural place for makers to contribute. Here you’ll find background information, research, ideas are being generated and prototyped, and in a few weeks the best ideas will be implemented.

The Challenge Grant is $5,000,000 set aside to fund prototypes.

Click here to learn how the OpenIDEO program works.

Let’s get involved; we can make a difference.

The Challenge has 25 days to go!

Packing for Eclipse Season


Animation of this week's lunar eclipse. Image by Tomruen via

This week’s eclipse, anim. by Tomruen /

Looking for pointers to protect your pupils before the partial solar eclipse? Read on.

The lunar eclipse Wednesday morning kicks off a series of blood moons, just in time to get in the Halloween spirit. Set your alarm clocks: you have to get up before the crack of dawn to witness this extraterrestrial marvel.


But then…. when the Moon swings around to the other side of the Earth in a little less than two weeks, most of the United States (and Mexico) get a peek at a partial solar eclipse on Thursday, October 23rd! (Sorry, New England! Looks like you’ll miss it.)

I have such fond memories of the last partial solar eclipse in my region, which peaked as we packed up at the end of Maker Faire Bay Area 2012. The sun snuck behind the moon, and the scene dimmed and was infused with the magic of this rare moment. Through every tiny hole, spooky crescent projections appeared. Thousands of natural apertures made by overlapping leaves created especially delightful shadows, as on the outer walls of Paleotool’s Vardo caravan trailer, pictured below.


LRgogglesThose final few moments of the event coincided with a partial solar eclipse viewable in San Mateo. Joy of joys, fabulous Maker Club Love & Rockets, far more prepared for this great coincidence of Makers and sunworshippers than I was, handed me a pair of paperboard and plastic solar viewing glasses that I continue to cherish and share with others. Love & Rockets’ Natalie van Valkenberg took a great picture of the eclipse through her pair of glasses, right. You can buy five-packs of these to get your whole neighborhood looking up at the sky with you on October 23rd.

LReclipse52012I pulled these glasses out for the Transit of Venus a short while after Maker Faire, and I brought them to my sons’ preschool so they could see the event too. I figured four-year-olds aren’t so good at holding them without accidentally taking them off and looking at the sun. (Natalie’s daughter, left, knows what she’s doing.)

So, worried that the silly kiddos wouldn’t pay heed to the instructions, I built something of a welding helmet made out of a box and the glasses. I made a hole in a box and taped the glasses inside the box. The kids put the box around their heads. Below, you’ll find a quick step-by-step of my eclipse glasses box, but now that I think about it it would probably work just as well by just attaching them in the middle of a much larger piece of cardboard. Little kids just have such a hard time keeping their fragile eyes covered since those viewing glasses are so small. I’d be eager to see others’ ideas!

eclipsebox-step1  eclipsebox-step2  eclipsebox-step3  eclipsebox-step4  eclipsebox-step5

I also brought along a pair of binoculars to use NOT to look at the sun directly but to use to project an image of the venutian eclipse onto a large white paper (which worked quite well, even if the preschool teacher mistook the image of the sun as Venus itself, rather than understanding the dot was the faraway planet. Sigh. Just think of the kids‘ misconceptions I fostered that day!)

LRwillseclipse52012You can use welding goggles to view an eclipse as long as you are certain they are rated 15 or higher.

But you don’t need to use fancy equipment to play with and witness this beautiful moment. All you need is a tiny hole. Take a piece of opaque board or foil to project the image of the obscured sun, pinhole-style, onto a flat, white surface the right distance away. Forget your hole at home? You can even make a tiny aperture with a curled finger or fist (as Will of Maker Club Love & Rockets showed us, right), or criss-cross your hands to create a matrix of moonshadows, as our friends at Evil Mad Scientist Laboratories demonstrated in 2012, below.


These four sites offer some excellent tips for packing your sun-viewing gear. Click around to start your plan for constructing your tools for seeing this phenomenon (without looking at the sun–so tricky!)

We’ve given you fair warning to build your gear! In exchange for this cosmic courtesy, we ask you to please take photos and video of what you make and how you make it and how it worked so that we can populate Make: with lots of great tips for ecliptical apparati ahead of the next solar eclipses. (I’m “totally” making my plans for a visit to Kentucky/Tennessee in August 2017 right now!)

Add links to your favorite eclipse-viewing tools and your own project write-ups in the comments below.