Outdoor Activity During Wildfire Smoke Events in Sonoma County, California

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Regular outdoor activity, aka exercise, is essential for good health. With climate change causing earlier and longer fire seasons in the western Unites States, and specifically Northern California, and the subsequent air quality degradation during the far-reaching smoke events generated by these fires, not only is our respiratory health under attack, but our ability to stay in shape is also at risk. This is an especially difficult situation for people who work outdoors for a living, delivery drivers, landscapers, maintenance workers, etc. The question in my mind as I did this research was:

“Is there any safe outdoor place to go to get away from the smoky air in Sonoma County where I could exercise?”

Keeping this in mind I was interested in understanding the prevailing wind patterns and other local environmental conditions that might make some areas better than others for outdoor activity in spite of the smoke events.


For several months, since August 2018, I have been monitoring daily news reports and searching the web for information related to air quality in the smoke effected areas in Sonoma County, California. I have analyzed the most relevant news and other data, such as air quality measurement applications, and made conclusions based on that, as well as my own anecdotal experience while living through these events in person.

I also spent a significant amount of time “in the field” observing the situation on the ground or in the air as the case may be. Where possible, I took photographs to compare the before and after air quality from a visual perspective.


Both anecdotally and through analyzing my news research, I discovered that there is an unusual situation occurring that causes these smoke events to be so bad, aside from the enormous sizes of the fires, and which may also be related to the weather that makes wildfire conditions so much more dangerous, aka, global warming.

A stable air mass that was stuck in the Bay Area did not allow the smoke to dissipate through normal wind patterns due to what is referred to as an inversion layer or temperature inversion. This exacerbated the smoke event making it much worse than it might have been. The smoke event in November (Camp Fire) lasted for 2 weeks. The smoke event during the Mendocino Complex fire seemed much longer, but less intense. Additionally, the amount of smoke and the height of the smoke was most likely unprecedented. I initially estimated that the smoke in Sonoma County was at least a mile high, taller than any local mountain peak. This was a personal estimate based on field observations. In fact, wildfire smoke eventually reaches very high altitudes and is dispersed for thousands of miles.


There is no safe place to exercise outdoors during these kinds of extreme ‘wildfire smoke event’ conditions. Indoor exercise is the best way to maintain physical conditioning, but even indoor air quality is poor during these events unless there is a good air filtration system present.

Personally, I took a hiatus from intense physical exercise and did yoga and mindfulness breathing which are both beneficial to physical health and mentally soothing during stressful times.



With the onslaught of the fire season in Northern California this summer and through the fall, and the expansion of that season due to drought and climate change, it’s becoming more and more difficult to do my weekly hikes, or even walk the dog for that matter, due to the extremely bad air quality.

For Sonoma County this situation began in mid summer with the initial fires in Lake and Mendocino counties, known later as the Mendocino Complex Fire1 and then again later in the fall with the Camp Fire2 in Butte county, over 100 miles away, the smoke from both events blanketed the Bay Area with a miles-high layer of pollution that lingered for weeks due to an inversion layer stalling the usual wind patterns3 that would have allowed the smoke to dissipate.

During the first smoke event (Mendocino Complex) I became curious as to whether there are areas where normal wind patterns in Sonoma County may leave the air more fresh, or less smoky, where I might be able to do some hiking up hill and not worry about breathing in the unhealthy smoke and other unknown particulates.

I began to spend several hours each week researching and following up on news reports during the Mendocino Complex fire in August-September. Then once that smoke cleared, there was a lull period, when the skies were blue and clear, until the now worst fire in California history began on November 8th, the Camp Fire. Local schools and some businesses had to close due to the danger of being outdoors with the poor air quality.

Indoor air quality suffered as well. The air quality monitor in my living room was constantly beeping, the display animation telling me to the open the windows. Of course that would have only made it worse; I couldn’t even see the nearest mountain from my house in Southwest Santa Rosa, Taylor Mountain, due to the smoky air, and the line of trees a few hundred yards away was barely visible.

On September 11, 2018, during the height of the Mendocino Complex Fire (then the largest known fire in state history), the PBS New Hour ran a report4: “Urban wildfires bring lingering worries about what’s in the ash and air” which showcased the efforts of UC Davis Air Pollution Scientist Keith Bein5,6, who, using specially outfitted electric cars, drove to various spots in Sonoma County to take air samples for chemical analysis. His system, the Rapid Response Mobile Research Unit, can “deploy at the drop of a hat” and get real-time data for public consumption. In spite of the concerns expressed in this report as to the contents of the pollution7 (think of all those burning cars, chemicals, and plastics…), and the obvious bad air quality and spare the air alerts, my child’s school was still requiring PE outdoors, including a weekly one mile run!

My personal experience during this smoke event was a general feeling of fatigue. I had no other symptoms though I heard people coughing and complaining of sore throats. I wasn’t spending a lot of time outdoors, so I think I missed the worst exposure to the smoke.

Two months later a fire broke out in Butte County that would prove to be the worst California wild fire in recorded history. This time the local school district had come around and put a policy8 in place to help them determine when it’s safe for students to attend and when the school should close. Similarly, the local colleges took a safer approach and cancelled classes on days when the air quality was considered dangerously bad. It is worth noting that Sonoma County is divided into two Air Quality Districts9, so local schools may have different inputs depending on how their district handles these smoke events. Using online apps such as AirNow.gov10 and PurpleAir.com11, the powers that be can determine the air quality based on a numerical particulate rating and a GIS-based visual system to show where the air is worst and where the air quality makes it too dangerous to be outdoors. AirNow and PurpleAir are different, so results may vary depending on which app is utilized. AirNow is an EPA-driven app, the sensors are fewer, but they are frequently calibrated. PurpleAir is community driven and has many more sensors. You can install one at your home and upload it to PurpleAir. However the quality of the readings may not be as accurate as AirNow due to less control over sensor calibration

My income suffered during this time since I work at Sonoma State University as well Santa Rosa Junior College, and also the Pepperwood Preserve…all three of which either closed or disallowed outdoor activity for several days within the two weeks of very bad air. More importantly, I felt the adverse-health-effects much more so than during the Mendocino Complex fire, with coughing and more fatigue. In this case it felt much more dangerous than the previous smoke event, but I was also more aware of the danger from my previous research in August-October.

In October I started a third part-time job at the Pepperwood Preserve, gathering tree data from a study by the Ackerly Lab at UC Berkeley to determine how the trees are recovering from the 2017 fires that raged through Sonoma County into Santa Rosa, at the time becoming the most destructive fire in California. The damage to the trees on the preserve was appalling, but the survivors were showing strong signs of recovery, having evolved to benefit from natural wild fires. Quite a few were completely gone. The intense heat of these modern fires is such that entire trees and their roots were seemingly vaporized; nothing left but a hole in the ground and empty tunnels where the roots once ran.

We missed several days of field work at Pepperwood during the two weeks of the Camp Fire smoke event. The stable air mass was finally freed during the Thanksgiving holiday when a series of storms began that cleared the air.

Camp Fire Smoke Event Field Research

On Thursday November 8th the Camp Fire started in Butte County. Fanned by the Diablo Winds12 from the northeast, the smoke from the fire quickly spread southwest13 to the Bay Area. The following morning, the smoke was so bad in Sonoma County, that many local schools were closed and employees of the schools stayed home. This fire ended up being the most destructive in California recorded history, with a death toll of 86 so far, and over 10,000 structures destroyed.

During and prior to the smoke event from this fire, I took several solo field trips to observe and photograph. On October 27th, prior to the Camp Fire, I had taken a field trip with SRJC’s Bio/ES 85.1 class on a transect across Sonoma County from Santa Rosa to the coast between Bodega Bay and Jenner. See Figures 1 and 2 for a comparison of the coastal air quality then and again on November 14th during the smoke event. While in Jenner on the 14th I spoke to the cashier at a gas station and he confirmed that the smoke had been much worse the previous day. I confirmed the same opinion with another cashier at a restaurant in Bodega Bay. A light wind had blown some of the smoke away, but the improvement didn’t last and more smoke arrived in subsequent days.

On November 12th I drove to the Pepperwood Preserve and took some photos of the smoke overlooking the Santa Rosa valley from the Bechtel House at 1220 feet in elevation. Compare these with photos taken in early October from the same viewpoint in Figures 3 and 4.

On November 12th I drove up Ida Clayton Road near Mt. St. Helena, to the highest point to which I could drive (hiking not advisable due to the smoke) to assess the smoke situation at over 2600 feet elevation. See Figures 5, 6, 7, and 8 taken at that location.

Figure 9 is a photo taken on November 9th near my home at the edge of Laguna de Santa Rosa, while walking my dog. This was less than 24 hours after the Camp Fire started and the smoke was already incredibly dense. It’s worth repeating that I live over 100 miles in a straight line from the Camp Fire’s origin point. Word has it that the Diablo Winds were blowing so hard in Butte County during the wildfire that it was consuming a football field’s worth of land every second! It’s no wonder that so many people could not escape such a maelstrom.

Figures 10 and 11 show screenshots of the air quality maps at PurpleAir.com and AirNow.gov for Sonoma County during the Camp Fire. The East Bay was far worse with an AQI14 (Air Quality Index) of 300-400 in certain locations! The smoke from these wildfires reaches half way around the world and effects people’s health far and wide15 whether they know it or not. Awareness is the key to staying out of harm’s way.


All photos, © 2018, Tom Hart

Figure 1 – Sonoma Coast before the Camp Fire, October 27, 2018, panoramic view from Coleman Valley Road near Hwy. 1.

Figure 2 – Sonoma Coast during the Camp Fire, November 14, 2018, regular view from the beach near Jenner.

Figure 3 – View facing Southwest from the hillside below Bechtel House, Pepperwood Preserve, before the Camp Fire,
October 26, 2018, Telegraph Hill peak to the far right.

Figure 4 – View facing Southwest from the front yard at Bechtel House, Pepperwood Preserve, during the Camp Fire,
November 12, 2018, Telegraph Hill peak less to the right.

Figure 5 – View of Mount Saint Helena from Ida Clayton Road during the Camp Fire, November 12, 2018.

Figure 6 – View of smoky sun from Ida Clayton Road during the Camp Fire, November 12, 2018.

Figure 7 – Altimeter at 2669 feet.

 Figure 8 – View of smoky sky at 2669 feet altitude, taken from Ida Clayton Road during the Camp Fire, November 12, 2018.

Figure 9 – View facing west toward Laguna de Santa Rosa, November 9, 2018, during the beginning of the Camp Fire.

Figure 10 – View of AirNow website, November 16, 2018, showing hazardous air in Bay Area…

Figure 11 – View of Purple Air website, November 16, 2018, showing unhealthy air in Sonoma County…


1. Wikipedia.org, “Mendocino Complex Fire”, https://en.wikipedia.org/wiki/Mendocino_Complex_Fire, Accessed Dec. 12, 2018

2. Wikipedia.org, “Camp Fire”, https://en.wikipedia.org/wiki/Camp_Fire_(2018), Accessed Dec. 12, 2018

3. Windmapper.com, http://windmapper.com/CA/observations, Accessed Nov. 10, 2018

4. PBS News Hour. “Urban wildfires bring lingering worries about what’s in the ash and air”, Sept. 11, 2018, https://www.pbs.org/newshour/show/urban-wildfires-bring-lingering-worries-about-whats-in-the-ash-and-air, Accessed Sept. 12, 2018

5. The Press Democrat, “UC Davis study to focus on post-Sonoma County fire pollution”, Jan. 24, 2018, https://www.pressdemocrat.com/news/7908232-181/uc-davis-study-to-focus, Accessed Dec. 11, 2018

6. UC Davis research program What Now! California: A Study in Urban Wildfires, “Wildfires and Health: Assessing the Toll in NOrthWest California”, https://environmentalhealth.ucdavis.edu/, Accessed Nov. 15, 2018

7. The Press Democrat, “Health risks of toxic ash feared in wake of Sonoma County fires”, Nov. 7, 2017, https://www.pressdemocrat.com/news/7606891-181/health-risks-of-toxic-ash, Accessed Nov. 9, 2018

8. SCOE.org, “Sonoma County Schools Air Quality Guidelines”, Nov. 13, 2018, https://www.scoe.org/files/Sonoma_County_Schools_Air_Quality_Guidelines.pdf, Accessed Dec. 12, 2018

9. Sonoma County Air Districts map, https://sonomacounty.ca.gov/Air-Quality/, Accessed Nov. 20, 2018

10. AirNow.gov, https://airnow.gov/index.cfm?action=airnow.local_city&cityid=320, Accessed Nov. 16, 2018

11. PurpleAir.com, https://www.purpleair.com/gmap?&zoom=9&lat=38.398606812601784&lng=-122.75201390000001&clustersize=29&orderby=L&latr=1.2735645379221978&lngr=3.402099832892418, Accessed Nov. 16, 2018

12. Abc7news.com, Oct. 15, 2018, “What you need to know about Diablo Winds and Bay Area wildfires.” https://abc7news.com/weather/what-you-need-to-know-about-diablo-winds-bay-area-wildfires/4490438/, Accessed Dec. 12, 2018

13. The Press Democrat, “Smoke from distant wildfire rattles nerves in Sonoma County”, Nov. 8, 2018, https://www.pressdemocrat.com/news/8930301-181/smoke-from-camp-fire-seen, Accessed Nov. 8, 2018

14. AirNow.gov, “Air Quality Index (AQI) Basics – AirNow”, Aug. 31, 2016, https://airnow.gov/index.cfm?action=aqibasics.aqi, Accessed Dec. 12, 2018

15. IQAir.com, “Wildfire smoke travels farther than you think”, https://www.iqair.com/newsroom/wildfire-smoke-travels-farther-you-think, Accessed De. 12, 2018

3 thoughts on “Outdoor Activity During Wildfire Smoke Events in Sonoma County, California”

  1. Thank you for your educational blog! I’m already looking into a few resources that were posted and I’m confident that this information has made me more mindful of my health during high smoke incidents.

  2. Thank you for your informative and Image enhanced Blog Site. i might mention that my car, a Toyota Corolla, developed a “Check Engine Light” condition during the fires. I took the car to a repair shop- they set the Light to off, and told me to come back if it ever went on again. The air cleared, and my “Check Engine Light” luckily didn’t come on again. I would have faced $300 in fees to just diagnose the Engine Light problem-even before a repair could be made! The smoky air did indeed cause harm, because I had to park my car outside at night and not in a garage.

  3. Hello! Breathing in that smoke during the wildfires was horrible. My husband and I gave birth to our son during the Santa Rosa fires and we were afraid to leave the hospital because it was so smoky. My husband wanted to take our beagle outside so she could get some outdoor time but I felt nervous bringing her out in the smoke too. It was a fine balance trying to cope and trying to live. I expect these fires will be a normal occurrence but at least we can all prepare for it I suppose.

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