Different Smokes

November 15th, 2018 by tony

The Camp Fire last Thursday

 

[Thanks to Jerome for the title; I was going to call this “Summer of Smokes” but both last year’s and this year’s gigantic fires actually took place during the fall and early winter. Most of you are probably old enough—although you may not have been living in the Bay Area at the time—to remember the 1991 Oakland Hills fire. Until last year’s Tubbs fire it was the most destructive fire in California history and it also took place in late October during the so-called “Indian” summer that we often get here.]

The current Camp fire near Chico, CA is blanketing the Bay Area and large swaths of the Sacramento and San Joaquin Valleys with massive quantitites of smoke and soot so much so that the Bay Area Air Quality Management District has issued alerts and “Spare the Air” days every day since last Thursday (eight days so far). Even San Francisco, which normally has good quality air compared to other Bay Area regions, has been in the “red” zone. The pollutant of concern is PM 2.5, particles less than 2.5 microns in diameter, although the Camp fire is also producing soot in particle sizes much larger than that but those particles don’t travel as far.

BAAQMD issues alerts when a composite index for all six major pollutant categories—PM 2.5, ozone, nitrogen oxides, sulfur oxides, CO, and PM 10—begin to rise. Normally in the Bay Area we are in the “good” (0-50) or “moderate” (50-100) category. But now we are seeing readings that put us in the “Unhealthy for Sensitive Groups” (101-150) and “Unhealthy” (151-200). Today Oakland hit 217 and SF 221. 200 and above is considered very unhealthy or hazardous; those are the kind of readings one might get in Beijing or New Delhi.

All of these pollutants plus a host of others that aren’t tracked are cause for concern not just because they might make the sky look hazy but because with prolonged exposure and at high enough levels they have noticeable health effects. If you have asthma or another chronic pulmonary condition, you might start to feel the effects of air pollution while everyone else around you seems to go about their daily lives with little or no idea that they’re literally drowning in smog. But eventually even hardier folks feel the minor signs such as coughing, burning eyes, and scratchy throat.

What makes these conditions concerning is that as cyclists we are not only outdoors breathing in smoke from the fires but exercising, which increases our respiration rate,so that we are probably breathing about eight to ten times more air per minute even at a relatively easy cycling speed. That means we are exposed to much higher amount of pollution compared to sitting at a desk indoors.

Smoke from the Camp Fire Spreads Throughout NoCal

Last October during the Tubbs fire the air quality jumped up and down subject to the whims of the wind, which changed hourly. At times the air was a hazy brown and the smell of smoke was pervasive; the next day it was sunny and clear even though the fires were raging just 40 miles away. I went riding anyway although I did make a concession by riding at an easy pace to reduce the amount of dreck I was inhaling. One day when the BAAQMD said we were in the red zone, I whipped out my Respro cycling mask that I had bought in London years ago for my daily commute to work here in SF. But the air in SF is generally so good especially out by the Pacific where I worked that I didn’t have a use for it. The Respro is a bit confining even though it’s miles better than a N95 mask. The Respro fits tightly—perhaps too tightly (I did buy the right size so they *are* supposed to fit tightly!)—and that’s good for blocking pollutants but bad when the weather is warm, which it was last October. Even though the Respro has exhalation ports that make it much easier to vent your breath, during hard cycling the mask just didn’t breathe well enough to be comfortable on a long ride. For commuting speed it’s mostly fine but I was out for a pleasure ride.

In retrospect it was foolish for me to ride during the fires because even though I had nothing more than an occasional hacking cough and some transient chest tightness, the long term effects of inhaling pollutants being potentially scary. PM 2.5 particles are so small that they can be inhaled deeply into lungs especially when exercising. Those particles not only obstruct the surface area of lungs and interfere with respiration but they also lodge there; very small particles can even pass into your circulatory system and go on to affect other organs. Exposure to pollutants also can set off an inflammatory response that further scars your lung tissue.

This year I didn’t make the same mistake and I’ve cycled only once—last Saturday when the forecast was for moderate pollution (which turned out to be incorrect—it was worse). The pollution is so bad that I doubt a Respro mask is able to cope with it all. We’ve stayed holed up in the house with the HEPA filter running. But we have to go out and run errands and the house is old and hardly sealed up so we are still getting a goodly share of smoke. Both of us are coughing like patients in a sanitarium and albuterol has become our BFF nonetheless.

If you’re young and robust, you’re probably ignoring the warnings and heading out for a good spin despite the smoke. Maybe that’s alright for now but in the long run it can’t be good. Ending up with COPD, lung cancer, or pulmonary fibrosis are not pleasant ways to die.

Well, the fires are just a transient hazard. Next week the high over the Rockies that is causing our offshore prevailing wind will move and we’ll return to our usual onshore flow and maybe even some rain. The smoke will change direction away from the Bay Area, and eventually the Camp fire will be extinguished. But chronic exposure to everyday air pollution is no good thing either and we have plenty of it with the enormous number of cars filing up and down our roads and highways. Diesel engines produce copious soot in the PM 2.5 range and regular gasoline automobiles create ozone both directly and indirectly. Even on days that have “good” air quality, pollution can be much higher in certain locations for example next to freeways. So avoid riding next to freeways or major roads with a lot of car traffic. Even better would be to go mountain biking away from roads, period.

A BAAQMD reading is for an entire day but the pollution changes from hour to hour. Particulate matter tends to be worse in the early mornings because of the night time stagnant air whereas ozone tends to be worse later in the day after tailpipe emissions climb. In addition the commute hours cause big pulses of pollution in the early morning and late afternoon. If you are riding during the week, you have to fit that around your work and home life and that likely means you’re riding early in the morning or after work, right when car pollution is peaking. On top of all that air pollution behaves differently at different times of the year. During summer with increased heat and sunlight we have higher generation of ozone and during winter temperature inversions and wood fireplaces mean higher PM readings in the late evenings, nights and early mornings.

With ozone generally peaking during the afternoon and PM more or less level during the day except at nights and early mornings during the cold months, the best time to exercise is usually going to be in the mid-morning. But another option is to wait until well into the evening when ozone has started to drop. With a good set of lights you’ll be able to enjoy that cleaner air. Years ago I often had to work until 7 in the evening. I’d rush home, change into my cycling clothes and head out over the Golden Gate Bridge to the Marin Headlands to clear out my head and get in a refreshing ride. With a good set of lights and being alert riding at night can not only be cleaner for your lungs but also safe.

Share

Leave a Reply