Air Quality, 2020 California Fires & U.S. Climate

Article listing vetted donation organizations (this also a bookmark for myself so I can come back and donate from time to time)

Here’s a Climate Map with a list of all U.S. Counties to see how it will be affected by Climate Change.

  • Purple Air Map (outdoors & indoors): Best choice. Crowd-sourced, real-time updates from personal PurpleAir sensors, now with EPA conversion for wildfire smoke.
    • Public PurpleAir Facebook group if you want to see users discussing their PurpleAir devices.
    • If your air is affected by regular pollution, no conversion recommended.
    • If your air is affected by wood smoke, use the EPA release conversion.
    • Learn more about conversion options here.
  • AirNow.Gov & Govt Air/Smoke Map (outdoors): Govt sensors that updates hourly or every some period of time. May not be accurate if you are not near the sensor station. Also, pls note: 
    • “AirNow actually does something more complicated than a 1 hour average that is delayed by up to 3 hours, but the basic idea holds: AirNow data is averaged over a longer time period and will be delayed compared to PurpleNow. See this link for more.” Quote Source
  • BAAQMD (outdoors): Related to AirNow. It gives you an hourly forecast of particulates and further beyond.
  • AirVisual (outdoors): Another good resource that sources their data from PurpleAir + their own IQAir sensors + extra data. It’s a compilation of a lot of sources. This site not only shows you air quality more densely than AirNow, but it also shows you where the fires are and the direction of the wind, so you can kind of take a guesstimate where your bad air is coming from. AirVisual also has a very useful iphone app.
  • AirBubbles (outdoors): This is an app you can download to see readings from govt sensors.
  • Wynd Air Tracker Halo Sensor (portable sensor): This is what I carry around, move around in my house, to check the air quality. Used it many years now on a daily basis. Good quality and reliable. If readings get off-track, you can re-calibrate from the app (the Tracker). I also use it to test if my air purifiers are pumping out clean air, or not (time to change the filter).

Updated: Sept 14th, 2020

With the fires raging, people are finding that purifiers are sold out everywhere locally and hard to find.

I built my own purifiers in previous years (I no longer need to this year). From my experience, this article here is the best/easiest method I would recommend to DIY your own purifier.
DIY purifier

It probably does. But those filters typically can’t be too dense otherwise it slows down the whole cooling/heating process of the building. Those filters are really meant to protect the HVAC system from clogs while letting enough air through. Therefore, those filters really only filter out dust, but not small particulates/viruses.

A MERV12 and higher filter is the minimum at which it starts to filter some PM2.5 out of the air, and even that could slow down the air coming from the HVAC. The downside of slowing down the air flow is that it could result in mechanical problems to the HVAC system as the MERV12 or higher filter gets more and more clogged.

Someone wrote a good article to explain this issue here (The Unintended Consequences of High-MERV filters). So if air purification is your thing, it’s best to go for a standalone one.

According to the EPA (PDF), wildfire smoke predominantly consists of fine particles in the 0.4 to 0.7 micron range.

Particles in the PM2.5 size range are able to travel deeply into the respiratory tract, reaching the lungs. Long term exposure to fine particulate matter may be associated with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer and heart disease. People with breathing and heart problems, children and the elderly may be particularly sensitive to PM2.5. [Source]

  • MERV
    • Stands for Minimum Efficiency Reporting Value
    • Used for HVACS and furnaces
    • MERV ranges from 1-16 (17-20 would be in the HEPA range)
    • MERV12 is the minimum rating that starts to filter out PM2.5 particles. Iirc, it’s supposed to filter out ~50% of PM2.5.
    • MERV values are not standardized and varies from one brand to the other
  • HEPA
    • Stands for High Efficiency Particle Arrestance
    • For air purifiers (or HVACS with HEPA compatibility)
    • HEPA is equivalent to MERV17-20
    • HEPA-type filters are non-standardized. Imitations that were not tested by any authority.
    • TrueHEPA filters are standardized and rated to remove 99.97 percent of all airborne particles of exactly 0.3 micron diameter in a single pass.

Added: Sept 16, 2020

Sharing this article “Managing Wildfire through Cultural Burning” for California at least

Added: Aug 25, 2020 (Watch CalFire daily Fire Situation Report videos on their Twitter)

Added: Aug 24th, 2020 Part 2

Fires burned my beloved Big Basin SP… but the redwoods will recover.

Lightning nearly struck another one of my magical places… the Lick Observatory, causing fires to sprout and get dangerously close to this observatory built in 1888.

Added: Aug 24th, 2020 Part 1

It’s 2020! And we have fires here in California again. By now, if you’ve read the historical posts below, you’ll know that I’ve really looked into air filtration. This update is to share the equipment that I’ve settled on for my family. I have to say, we fared much better this fire season than in previous years because of all the improved equipment. (I gave away all of my DIY purifiers ever since my Kickstarter backed Wynd Max Purifier arrived. One Wynd Max had more power than all of my homemade purifiers put together.)

Main Common Area: The area that we spend the most time in all day. For this area I use the new Wynd Max Home Purifier. It features dual HEPA filters (from research you would know that you only need HEPA filters and maybe a charcoal filter, that all other types of filters are just gimmicks) which can clean out the air in a large room in a brief amount of time. When stuck inside the house all day (or maybe multiple days), the air starts to get stale, so inevitably you’ll need to let in some outside smokey air, and this is where the Wynd Max proves its value… by cleaning up that outside smokey air ASAP so you don’t spend as much time mired in it.

I also use the Wynd Halo sensor with this. There are times when the outside air is smokey, but I need to circulate it inside anyway to combat the stale air.

Here are my steps to circulate air when it’s smokey outside:

  1. Place the Halo sensor near the open window where outside smokey air is being let in and remember what color it started as
  2. Place the Max purifier a short distance away from that window
  3. Keep an eye on the Halo sensor and when it changes more than 1 shade of color, I close the window back up
  4. Let the Max purifier work
  5. When Halo sensor gets back to the starting color, I repeat this process if needed

Overnight in Bedrooms: I have a second Max Purifier that I keep in the room where we sleep all night, because on some nights the outside air is in the Red/Purple zone and it’s unsafe to keep the window open even a crack.

Small Rooms/In The Car/Portable: I have 3 of the Wynd Portable Purifiers, which I call my Cuppa-Fresh-Air, that I move from room to room, or to the car when I’m out driving. These have worked well for small rooms that we spend a few hours in day-to-day, and work well when in the car.

What did I do with my RabbitAir? Why did I get a 2nd Wynd Max Purifier instead of another RabbitAir?

This year my parents stayed in the country instead of traveling overseas, and so I gave my loyal and dutiful RabbitAir BioGS1 purifier with a new filter to my parents. Since I gave the RabbitAir away, I needed a replacement and that’s how I ended up with a second Wynd Max Purifier. From an equipment-cost perspective, the Wynd Max Purifier (dual HEPA) was cheaper than a new RabbitAir (single HEPA). From the ongoing-cost perspective, filter replacements are cheaper with Wynd also, as Wynd sells 2 replacement HEPA filters for ~$70 while RabbitAir sells a single replacement HEPA filter for ~$50.

If anyone actually decides to get a Wynd device, here is my Wynd referral link where you get 10% off. I’m not sure what I get, since I’ve never given it out before.

With the onset of climate change, California has been seeing spates of wildfires in recent years, causing unavoidable poor air quality sometimes for days.

Here are some tips for staying safe with the poor air quality lingering around:

  • INSIDE: Stay indoors and keep windows/doors closed. Use an Air Purifier
  • CAR: Turn ON Air Re-circulate in your car
  • MASKS: If you have to be outside wear N95 or higher rates masks. Don’t re-use masks, only new ones will work and must be tight to your face. These masks don’t work well on kids.
  • LAUNDRY: Wash all your clothes as often as you can, since particulates will linger in your clothing and get into the air as you take it off/put it on, etc.
  • MOP: Particles eventually land on the floor, so mopping or HEPA vacuuming is a good choice.
  • HUMIDITY: Keep you place at a decent level of humidity.

Finally… one way to keep the air clean at home is with an air purifier. 

I bought our air purifier in 2012 thinking I’d only use it on the rare occasion, who could’ve known that we now have to use it almost weekly. After some research, I settled on the BioGS1.0 from RabbitAir. It is many years old now and still running well.

  • Maintenance: My BIOGS1.0 is extremely easy to clean. I pull off the front panel, and remove 3 panels of filters. The pre-filter and charcoal can be vacuumed/washed. The HEPA filter, I just toss and replace.
  • Frequency: Maintenance every 3 months and replace the HEPA filter annually, if used 24hrs/daily.
  • Noisiness: It’s an extremely quiet machine, that I can leave running at night while sleeping.
  • Effectiveness: It cleans out a small bedroom in about 30 minutes and a large living room area in a couple of hours. (I used to leave it by the laundry room and would watch the little specks of lint/dust float into its grills.)
  • Automation: Option to self-adjust filtration level based on air quality using its two sensors (dust and odor).

This tides us over until the air outside recovers and we can open our windows again…

Update 11/13/2018:

I’ve also now begun researching portable purifiers for the car, since we commute so much and the re-circulate option is pointless when the air outside is filled with smoke and we are getting in/out multiple times a day. Basically, since our car doesn’t have a built-in HEPA filter, our bodies are the filters… breathing all that air that gets mixed in each time the door gets opened.

Update 11/13/2018 #2:

Every time I sit in my car, I start to feel a light headache. Even though we have the air on re-circulate in the car, due to the kids, the door stays wide open for long periods of time and bad air gets in and trapped inside. I searched for a car/portable air purifier and could only find cheap ones that break down in two months according to reviews. Finally, I found Wynd, a Kickstarter product that came out a couple years back. Sadly, Amazon, wouldn’t ship to my address but that led me to contact Wynd directly and I discovered that they were local in Redwood City.

Their customer service was very responsive and within an hour I was able to drive there and pickup two sets of Wynd Plus kits. Once I plugged it in and turned it on, I was shocked to see the air quality reading in my car.

Wynd Portable Air Purifer

(Amazon Link, sold-out, but you can still check the reviews. Update: Now sold in Apple Stores.)

Wynd ​​Tracker reading in my car
Wynd ​​Tracker reading in my car

I kept it on and by the time I got home, it registered at:

After a 30-some minute drive with Wynd running in the car​​

I did notice slightly less smokiness in the car and my headache was getting lighter.

Once I reached home, I setup the Wynd Tracker around some spots in the home to see how my RabbitAir did. Surprisingly, my RabbitAir wasn’t doing so well. The air immediately around the RabbitAir was good, but everywhere else was also registering in the red.

The room adjacent to the one my RabbitAir registered very red, even though it’s connected by two hallways.

Air quality in the room connected to where my RabbitAir was running

And then the room where the RabbitAir was actually in:

On the far side of the room where RabbitAir was running on auto-mode

So even though we have the RabbitAir running on auto-mode, you can’t really quite tell if it’s doing enough (I should have probably set it to Turbo mode this whole time) without some kind of accurate sensor versus the little bars on the RabbitAir screen. The only thing we know is that in the car I had more acute headaches while at home I don’t, but clearly there’s a lot more purifying needed in the house.


1.) Portable air quality sensors are useful.

2. ) Car/Portable Air Purification is important (if you spend a lot of time in the car or at work with questionable filtration)

3.) Home Air Purification is important.

The little Wynd Air Purifier + Tracker covers 1 & 2. Now it looks like Wynd is planning on taking care of #3 as well. I stopped by their little startup office today and they revealed to me that they will be launching a new product tomorrow morning on Kickstarter that takes care of in-home air purifying with a more full-featured sensor.

Here are the links to the products mentioned above:

Update 11/16/2018:

Quote from Mercury News regarding prolonged air exposure:

“In Oroville and Chico, where unofficial air quality levels were around 500, breathing the air for 24 hours brought the equivalent health risk of smoking a pack of cigarettes a day, according to a calculation done several years ago by Richard Muller, a professor emeritus of physics at UC Berkeley. The “very unhealthy” levels in parts of the Bay Area would be like smoking half a pack, and the “unhealthy” levels reported elsewhere would be like five or six cigarettes.”

Updated: Sept 24th, 2020
These are the old DIY purifiers I played around with and tested with my Wynd Tracker sens0rs. Just keeping this old data here in case it’s useful.

Once again California is engulfed with fires. This time, the air in my area has mostly stayed in the yellow range, teetering on orange at brief intervals. So I did further research on economic ways to keep the air clean because though we are all set at home, our kids classrooms don’t all have HEPA Purifiers and it would be nice if I could provide an economical solution.

From my research and with the assistance of my Wynd Air Tracker, I’ve successfully made a purifier with just a box fan, duct tape and a True HEPA filter refill, though it’s not ideal because the fan is larger than the filter (very few fan choices at the store in late fall/early winter).

How to build your own?

Materials Needed:

  1. A Fan with a flat face
    • The more powerful your fan, the speedier it will filter.
    • Try to match the filter/fan size. But if it doesn’t it will just take longer to clean all the air in the room, but it will still clean.
  2. A “True HEPA” is preferred (lower preferences are HEPA-type or at the very least a MERV12) Filter Refill. If you don’t know the difference, scroll lower.
  3. Optional: Carbon Filter
    • A carbon filter is nice to have to handle odors/VOCs
    • If you plan to use these year-round, only these two filters are ever really needed/useful… a TrueHEPA and a carbon one.
    • (All other filters are more gimmicks and not essential)
  4. Duct tape or some kind of fastener.
  5. Optional: a Sensor to test.
    • If you are using a TrueHEPA filter. You don’t need to test. It’s industry standardized and verified.
    • If you are using a HEPA-type filter or a MERV filter. You probably want to test.

What’s the quick/economical build I used above?

  • Filter: Merv-13 filter that covers the face of the fan. Face the filter according to its airflow.
  • Fan: Any fan with a flat face that is not larger than the filter
  • Duct Tape: White Duct Tape from Amazon (for aesthetics since I went with white)
  • Sensor (optional): For my sensor, I use the Wynd Air Tracker. (The Wynd Personal Purifier, which includes the air tracker, can now be purchased at Apple Stores as well.) Or you could purchase a particle meter.

At these prices, you could afford to build several, one for each room in your home or even donate some to a school/community if desired.

How did I hear about this?

I’ve done some research online since the huge fires 2 years ago. I’ve found that other parts of the world constantly live with this problem, like China, while us Californians have only recently had to face this issue, so a lot of bloggers have posted their findings online. (Of course, I can’t do any testing until our own air turned bad, since it’s usually very good when not burning up.)

Here is the most comprehensive reference I found on DIY Air Purifiers (they even address the question of putting the filter in front/behind the fan):

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