by Alan Pryor
GUEST COMMENTARY – While many Davis residents are aware that the Davis City Council is considering a Staff recommendation on wood burning restrictions this Tuesday, few probably realize that there are actually 2 additional somewhat competing recommendations that the Council is considering. One is a long-awaited “Guidance” document submitted by the Yolo Solano Air Quality Management District. The other is a recommendation passed 6-1 by the Natural Resources Commission resulting at their September meeting.
Each of these recommendations or proposals are similar in that they would prohibit wood burning on certain days when PM2.5 (particulate matter less than 2.5 um diameter) concentrations in the region are expected to exceed certain thresholds. Each of the recommendations also differ with respect to which projected PM2.5 threshhold is used to issue mandatory “No-Burn” advisory, which air quality agency’s PM2.5 projections are used, and whether EPA Phase II stoves and pellet stoves are exempted from compliance with the otherwise mandated “No-Burn” notices.
The 1st part of this article discusses and compares similarities and differences between the various recommendations. The 2nd part addresses questions pertaining to technical specifications of the recommendations and the potential impact this would have on public exposures to PM2.5 and costs associated with the program.
Part 1 – Following are three tables providing a simplified comparison of the 3 different recommendations for wood burning restrictions presented to Council
(a) All include exemptions for loss of electrical power and low income hardships
(b) All proposals allowing for restricted use of EPA Phase II and pellet stoves include the requirement for no visible emissions after start-up
Re: NRC and Staff Proposed Exemption of EPA Phase II Stoves and Pellet Stoves
Both Staff and the NRC recommended exemption of EPA Phase II wood stoves and pellet stoves under their respective proposed wood burning ordinances that will be considered by Council this coming Tuesday. Conversely, the YSAQMD stated in their Guidance document included in the Council packet, “Allowing operation of these devices could still result in “nearest neighbor” complaints and might not achieve the ultimate policy goals”. (referring to use of possibly exempted EPA Phase II stove and pellet stoves during otherwise “No-Burn” days). A member of the Davis Wood Smoke Scientific Advisory Committee also wrote, “…continuous or longer-term use of even these more efficient wood burning devices can still result in excessive wood smoke exposure to nearby downwind residents. This is especially true at the low wind speeds during which mandatory no-burn advisories are likely to be issued“.
Question – If operation of EPA Phase II stoves can result in excessive downwind exposures under typical “No-Burn” day advisories, why did the NRC and Staff recommend that EPA Phase II stoves be exempted from its recommended wood burning ordinance?
Answer – It is unknown why Staff proposed this exemption and not explained in their proposal to Council. As for the NRC-proposed exemption, this was proposed simply as a political compromise without any scientific underpinnings. Past Councils and Staff had consistently rejected previous NRC science-based proposals using wind speed dispersion modeling as being too restrictive. Some members of the NRC proposed that exempting EPA Phase II wood stoves was something that Council might consider implementing even though the underlying science clearly indicated that operation of EPA Phase II stoves under such weather conditions common to “No-Burn” days would very likely result in excessive exposure to immediate downwind residents.
Inspection of the 3rd column in Appendix A at the end of this document (the dispersion modeling results previously used by the NRC to formulate its wind speed-based recommended proposals) clearly shows that use of an EPA Phase II stove can produce 24 hour PM2.5 exposures to immediate downwind residents that are far in excess of allowable federal standards. For instance, even with winds up to 2.5 mph during the night and overcast days, use of an EPA Phase II stove would likely produce downwind maximum exposures of from 125% to over 300% of allowable federal standards.
It is worth further noting, however, that the EPA is now in the process of promulgating more stringent standards for EPA Phase III wood stoves which are expected to be implemented early next year. The wood stove industry can now routinely produce wood and pellet stoves that will produce down to 2 g PM2.5 per hour if properly operated and the EPA is expected to recommend these values as its new standard for wood stoves. Use of such devices could result in emissions about one-quarter of current standards and these lower emission devices can probably be safely used under somewhat stagnant air conditions. These appliances are currently rare in the real world, however, as very few such units have been manufactured and sold to date.
Some producers of manufactured logs have commissioned studies which indicate that burning their products in a non-EPA Phase II wood stove will produce emissions only about 25% of the emissions produced by burning Douglas fir cordwood with 20% moisture levels under similar conditions. However, others have pointed out that this is not a fair comparative evaluation because 20% moisture Douglas fir is not considered to be nearly as clean burning as very dry hardwoods such as almond, walnut, or oak firewood. These detractors point out that the emission profiles of these manufactured logs when burned are only slightly better than when burning very dry hardwoods. For this reason neither the Sacramento Air Quality Management District, the Bay Area Air Quality Management District, or the San Joaquin Valley Air Pollution Control Districts allows exemptions from wood burning restrictions for manufactured logs.
Question: If manufactured logs are not substantially better in reducing emissions than seasoned hardwood, why did the NRC propose to exempt manufactured logs?
Answer: As with EPA Phase II stoves, manufactured logs are newly-proposed to be exempted by the NRC in an attempt to obtain political acceptance by offering a perceived slightly less environmentally damaging option. However, this proposed exemption is NOT based on a rigorous scientific analysis of the resultant “nearest neighbor” impacts resulting from the use of manufactured logs. That said, a manufactured log burned in an open hearth fireplace may show about the same emission profile as burning somewhat marginally dried Douglas fir cordwood in an EPA Phase II device. Thus, they would still be expected to produce PM2.5 exposures in excess of federal standards to immediate downwind neighbors.
In Sunday’s Enterprise, Bob Dunning wrote, “Even more telling, Cahill adds that “models used in a recent City of Davis study show the local ground level impact is enhanced for wood stoves because its cooler smoke tends to hang closer to the ground, compared to the generally hotter and more buoyant smoke from an open hearth fireplace.“
Question: If this statement is true, why are open hearth fireplaces so stringently regulated under low wind speed conditions as might exist under “No-Burn” day advisories?
Answer: Dr. Cahill is partially correct and only for a very narrow range of atmospheric conditions. Firstly, a close examination of Appendix A will show that EPA Phase II wood stoves do not burn cooler than open hearth fireplaces as quoted in Bob Dunniing’s column. In fact, they burn quite a bit hotter than open hearth fireplaces and that is why their combustion efficiency is higher. Open hearth fireplaces can, under a very limited set of conditions, produce projected lower ground level concentrations of wood smoke than EPA Phase II wood stoves under identical weather conditions. This is because the volume of wood smoke from chimneys of open hearth fireplaces is so much greater that it substantially increases the chimney escape velocity of the hot, burned gases.
This air exits at such a high velocity from the chimney that it can literally punch a “hole” through a low hanging inversion layer and be dispersed higher into the atmosphere. As I said, however, this only occurs at very low wind speeds and a very low inversion layer. If the inversion layer is slightly higher and/or higher wind speeds prevail, the excessive amount of wood smoke produced by an open hearth fireplace is pushed back down to the ground producing far higher concentrations and exposures to wood smoke to immediate downwind neighbors as shown in Appendix A
Dispersion modeling shows us that even given this phenomena, the resultant concentrations of wood smoke produced by open hearth fireplaces under low wind speed conditions (e.g.2.5 mph) can still produce wood smoke concentrations exposures in excess of the 35 ug/m3 federal standard and thus present a danger to susceptible populations particularly if regional air quality is already compromised.
Simply put, burning in open hearth fireplaces even under low wind conditions is still dangerous to your neighbors’ health. And, of course, as wind speeds pick up and effectively push more of the very high levels of wood smoke produced by open hearth fireplaces down to ground level, the wood smoke concentrations can become even more injurious to respiratory health. Thus, open hearth fireplaces can produce ground level concentrations of wood smoke with far more adverse impacts than Dr. Cahill’s and Bob Dunning’s interpretation of the data would otherwise indicate.
Both the Sacramento AQMD and the YSAQMD use the same outside consulting firm (Sonoma Technologies, Inc. – STI) to make their daily district-wide PM2.5 projections. Because there is remarkable similarity in the overall district-wide average PM2.5 concentrations (as previously demonstrated by both Tom Cahill and the YSAQMD) and the day to day measured changes are so consistently similar, it is believed that either agency will provide very close approximate concentration projections with no material difference. The Sacramento AQMD has historically had a slightly higher daily projected PM2.5 but their trigger points for calling for “No-Burn” advisories are also slightly higher. That said, both air quality agencies called for an identical number of “No-Burn” days last year (38).
Question: Why did the NRC recommend using the Sacramento AQMD as the agency for issuing “No-Burn” advisories instead of the Yolo Solano AQMD in whose district Davis resides?
Answer: There are two reasons the NRC recommended using the Sacramento AQMD as the lead agency for issuing “No-Burn” advisories. The first is that the Sacramento AQMD “No-Burn” advisories are disseminated through a far broader network of regional TV and radio stations and newspapers than those advisories issued by the YSAQMD. Thus, there is a greater likelihood of Davis residents actually becoming aware of the daily “No-Burn” advisories issue by the Sacramento AQMD. Plus the Sacramento AQMD has a far larger public outreach and educational budget than the more provincial YSAQMD. The 2nd reason is that the YS AQMD has declined to support mandatory wood-burning restrictions in Davis over the six years so there is a question of their ability to provide support services to the City.
It is worth noting that the unusually high number of “No-Burn” advisories last year (38) was unique over the 120 day season, and due to the unusual stagnant, dry weather patterns across the state. By comparison, two years ago when normal weather patterns prevailed, only 16 “No-Burn” advisories were called by the YSAQMD – or greater than 50% fewer days than last year.
The YSAQMD’s current district-wide daily “No-Burn” advisories are partially based on daily PM2.5 concentrations as measured at a monitoring station maintained by the California Air Resources Board located off Gibson Rd. in Woodland. The YSAQMD has stated that they believe their daily projections of PM2.5 concentrations would be enhanced for Davis if they instead base their projections on daily PM2.5 concentration readings taken from the YSAQMD-maintained monitor located west of Hwy 113 on rural UCD property. However, they have estimated this would cost the City about $7,000-8,000 annually following an initial cost of $29,000 to provide these special services.
Question: Will these extra costs to the City result in more accurate PM2.5 projection specific to the City of Davis?
Answer: As discussed above, the pattern of regional PM2.5 concentrations are very closely related across both the YSAQMD and the Sacramento AQMD. Indeed, the YSAQMD’s own data supplied to the NRC show very little overall differences between Woodland and Davis on a day-to-day basis. Some days Woodland is a little higher than Davis. On some days, the opposite is true. On average, the Woodland monitor reads about 1-2 ug/m3 higher than the Davis monitor but that is really likely more a function of the more rural location of the Davis monitor. In fact, being closer to the urban center in Woodland may more accurately reflect urban conditions in Davis than a Davis monitor in a field far removed from any wood burning sources. As a result, using the Davis monitor as a source for PM2.5 projections may even serve to underestimate conditions in central Davis. If Council chooses to use the YSAQMD projections as the basis for “No-Burn” day advisories, it would be technically and economically well advised to adhere to the current YSAQMD method of projecting PM2.5 concentrations based on the urban Woodland monitor without charge rather than the rural Davis monitor. The old adage seems to ring true, “Why buy the cow when you can get the milk for free”.
The Council will be weighing all these issues this Tuesday evening. The agendized item will probably not come up for discussion until at least after 8 pm as the Council is first considering the proposed selection of the surface water project and plan for the election next Spring.
Wow… I will have to sit down with a cigar on the patio while BBQ ribs are smoking on my backyard smoker to digest all of this. But I better do it quick before those things are banned too.
Seriously though, thanks Alan Pryor for providing a comprehensive source for our frequently asked questions.
Note… my wife has mild asthma. We replaced our wood-buring fireplace with a gas insert many years ago. However, the neighbor next door and the one across the street burns wood. It never bothers my wife. In fact, she comments how good the neigborhood smells when the weather is cold and those fires are burning.
We have very good windows and weather-proofing, and we rarely smell that smoke indoors.
I think this effort to ban wood-buring fireplaces is a solution looking for a problem.
To Jeff Boone re: “…my wife has mild asthma…the neighbor next door and the one across the street burns wood. It never bothers my wife. In fact, she comments how good the neigborhood smells when the weather is cold and those fires are burning….I think this effort to ban wood-buring fireplaces is a solution looking for a problem. “
Your wife is lucky her asthma is not so severe. I have heard from literally dozens of Davis residents who are otherwise adversely affected by wood smoke. Some can’t take walks on the streets on smoky evenings. Others can’t do yard work on some days if their immediate upwind neighbor is burning. Some residents have resorted to putting tape around window and door frames each winter to keep out the pervasive wood smoke. Some have written to me that their asthmatic children have to be called inside each evening when their neighbors start burning as the smoke can trigger asthma attacks. These are real people with real problems looking for any solution that cleans their neighborhood air
alanpryor,
Most people with severe asthma are restricted from walking outdoors when the wind blows hard, and there are dust particulates in the air. They cannot handle fumes from various things and must take precautions.
If they have such a problem with wood-burning fireplaces, I suspect they would have similar problems with charcoal-burning BBQs and my very expensive backyard pellet smoker.
I have sympathy for people with health issues, but I cannot accept that the rest of us have to lose so many freedoms to help compensate. It is just their bad luck that they cannot take a walk on dusty windy days and cold days when neighbors are burning wood for heat.
You mentioned taping windows. As I said, retrofitting a house with good windows installed correctly, and weather-stripping should prevent particulate matter from entering the house. Also, for people with severe asthma, they should have air scrubbers installed in their homes. The valley is a bad place to live if you suffer from severe asthma.
Watch out Jeff, you’re going to be called selfish and callous. I’ll bet you also sent your kids to school with thick peanut butter sandwiches.
If I owned an EPA phase II stove I wouldn’t be feeling too secure about that right now. Just a matter of time?
“As for the NRC-proposed exemption, this was proposed simply as a political compromise without any scientific underpinnings. Past Councils and Staff had consistently rejected previous NRC science-based proposals using wind speed dispersion modeling as being too restrictive. Some members of the NRC proposed that exempting EPA Phase II wood stoves was something that Council might consider implementing even though the underlying science clearly indicated that operation of EPA Phase II stoves under such weather conditions common to “No-Burn” days would very likely result in excessive exposure to immediate downwind residents.”
“I wouldn’t be feeling too secure about that right now. “
You’re talking about a handful or two of days in question, not a threat to your usage overall.
Which days will I not be able to use my older wood stove? If the days will vary, how will I know? Could the ban ever be in force on Thanksgiving or Christmas holidays? If we have a power outage, will the ban immediately lift?
I know Ryan, what a fricken nightmare.
Ryan:
Good questions.
“Which days will I not be able to use my older wood stove? If the days will vary, how will I know?”
The atmospheric conditions will determine it. The city plans to list them on their website and the government channel, but I think a reasonable complaint to the city is their antiquated communications system needs improvement.
“Could the ban ever be in force on Thanksgiving or Christmas holidays?”
As I read this yes, but again I think a reasonable amendment would be to change that.
“If we have a power outage, will the ban immediately lift?”
Yes
[quote]”The city plans to list them on their website and the government channel.”[/quote]
You have to have internet to view the city’s website and Comcast cable to view the government channel. Maybe a phone number to call with an announcement would be better. Many people don’t have a Comcast cable subscription and some not even TV. You’re right. The City does not have a way to really announce things on a day to day basis. The people who care will be all over it and the people who light a fire a few times during the Winter will not follow it.
If you amend it to not ban on winter holidays, that should wipe out the end of December and the beginning of January as possible ban days.
Thanks Alan for the thorough write-up on the technical aspects of the proposed ban (limitation). I am still wondering about the enforcement aspect of it. One question that may have been answered and I missed it. Who would be fined in the scenario where multiple unrelated inhabitants in a rented house, duplex, etc., were found to be in violation? Also is the DPD the entity doing the citing?
[quote]Could the ban ever be in force on Thanksgiving or Christmas holidays?[/quote]
Current programs in the Sacramento AQMD, the Bay Area AQMD, and the San Joaquin Valley APCD do NOT have exemptions for holidays and they have called wood burning restrictions on various holidays in the past. In fact, the Sacramento AQMD called a No-Burn nighton Christmas last winter and despite the wood burning restrictions it turned out to be the night with the highest PM of the season. It reached a level considered dangerous even to the general population.
While you may think that not having the ambiance of a fire may wreck your Christmas festivities, I can assure you that a holiday trip to the ER with a parent or child wheezing from an asthma attack kind of trumps it…and I have been there. Having a loved one with severe asthma that can have attacks triggered by neighborhood wood smoke completely changes your prespective about the rights of others to burn vs your rights for clean air. Lots of people in Davis have this problem and some at times become functional prisoners inside their own homes because the outside air gets so bad. They have complained to the City about it and I know some of the folks and know their respiratory problems on bad air days are real. I just think these people deserve some protection on the worst air days… holiday or not.
During the burn season, Sacramento has a number to call to see if it is a burn day. If we use the Sacramento burn/no burn days, anyone with a television OR a radio OR a subscription to the Bee OR a subscription to the Davis Enterprise OR a computer and web access OR a telephone will be readily able to find out what days are burn days.
“If you live in Sacramento County, call 877-NOBURN-5 (877-662-8765) from November through February to Check Before You Burn. A recorded message will tell you the daily burn status.”
[quote]Who would be fined in the scenario where multiple unrelated inhabitants in a rented house, duplex, etc., were found to be in violation? Also is the DPD the entity doing the citing?[/quote]
The person who actually lit the fire would probably be the person receiving the warning. But you’re right in that it may be confusing if there are multiple occupants in a rental. Don’t have the exact answer for that yet.
Current enforcement plans envision using the City’s Enforcement Officer (such as is used for weed abatement and building permit violations)to write letters to offenders during the first season.
Alan, I have lived here for many years and know many peope in Davis through my kids schools, church, political campaigns, service organizations, employment, recreational activities, sports, family and friends of all ages and varying levels of fitness and health. I have family members who had asthma, but they seemed to only have trouble managing their condition during the smoggy summer months, not during the Winter with intermittent rain. I have never, in any of these groups or activities, met someone like you describe – someone who is so allergic to the smell of fireplace smoke that they have a life-threatening reaction or are “functional prisoners in their homes.” Is banning residential fires just low hanging fruit?
Ryan:
” Is banning residential fires just low hanging fruit?”
Just to clarify again, it’s banning residential fires on days with certain atmospheric conditions.
Alan, Thank you for taking the time to provide this information. It’s very helpful.
Barbara wrote:
> If you live in Sacramento County,
> call 877-NOBURN-5 (877-662-8765)
> to Check Before You Burn.
It is funny that David recently posted that it would be unfair to make someone without an ID make a call (even if they had a free “Obamaphone”
http://www.youtube.com/watch?v=tpAOwJvTOio )
to get an ID before they vote, but it is just fine to require people to make a call every time they want to have a fire at home…
From Dunning’s column this morning:
“thanks to some eagle eyes scrutinizing our wood smoke data, we now know that during the 120 days of last winter’s “burn” season, only five individuals complained about wood smoke in the air … that’s out of a city of 65,000 people, many of whom don’t hesitate to complain when something offends them … those five individuals, three from the same general area of town, were responsible for all 65 complaints registered during those 120 days … for my money, such a dramatic lack of complaints indicates our voluntary compliance with no-burn days is working exceedingly well …”
Wouldn’t it be even more interesting to learn who those five individuals were.
When I used to work in a legislative office, they taught us that each letter writing complaint represented another 99 people who felt the same way and didn’t complain. It’s worth noting that when my wife got sick from exposure to smoke, we didn’t complain and in fact had no idea where the smoke was coming from.
I agree with a point that Medwoman made that complaints is probably not the best measure – ER visit statistics for asthma might be a better measure. Then again, the real health effects are long term cancer and other lung diseases that we cannot measure short term.
David:
“When I used to work in a legislative office, they taught us that each letter writing complaint represented another 99 people who felt the same way and didn’t complain.”
Where have I heard that before? That’s the claim anyway, anything it takes to try and trump the number of complaints.
Sorry that I remain unconvinced – and demonstrated it with anecdotal evidence – that complaints are the best metric.
What percentage of the people even know when a no burn day is and know to complain that that has been violated?
David wrote:
> When I used to work in a legislative office,
> they taught us that each letter writing complaint
> represented another 99 people who felt the same
> way and didn’t complain.
If five crazy people from Davis write to complain that Obama should be removed from office because he is a space alien and has a fake birth certificate does that mean that almost 500 other people in Davis feel the same way?
We have five crazy people in Davis that hate fires (and probably hate their neighbors who have the fires even more). I wonder how much we have spent for the City of Davis, the NRC and the YSAQMD to continue to study this to make the five crazy people happy.
You’re of course presupposing that five people would write in about such a matter. Then again, given the absurd claims I have seen, I no longer give the benefit of that doubt that there wouldn’t be 500 people feeling the same way.
You’ve decided to equate the position of the complainer as crazy, and as hateful. Then again, I assume you didn’t have to rush your spouse to ER for a breathing treatment.
In my opinion your hypothetical has too many incongruities to really have any real explanatory power.
Using David’s theory that for every complaint there’s 99 others:
1 in a town of 100 would mean the whole town felt the same way
1 in a city of 65000 would mean that 100 others felt the same way
1 in a city of 1,000,000 would mean that 100 others felt that way
Sorry, but the numbers just don’t pan out.
GIANTS ALL THE WAY!!!!
David wrote:
> I assume you didn’t have to rush your spouse
> to ER for a breathing treatment.
I have never had to take my spouse to the ER, but as a kid with bad asthma I went to the ER more than half a dozen times. Unfortunately my kids seem to take after me and have been to not only the ER here in Davis, but have had to spend the night at Sutter Sacramento for overnight breathing treatments (and blood oxygen monitoring). Like a lot of kids with asthma I’m a lot better now, but sometimes something that kicks up a lot of dust (like the tomato harvesters when I walked by a field with my dog last month) will make it hard for me to breath. I made a mental note to remember to turn around when I’m walking my dog and I see the big machines in the fields vs. the crazy response of trying to ban mechanical tomato harvesting in Yolo County…