SPECIAL TO THE VANGUARD –
Based only on the results of the stationary monitoring, though, Dr. Cahill concluded the following
“Aerosols measured in Davis were often equivalent to those measured in downtown Sacramento at the same time, confirming earlier evidence that the aerosols in central Davis are regional in nature, not locally generated”, and
“The freshly generated smoke values are about the same at both sites, indicating transport probably on the nighttime eastern (down-slope) winds from the foothills and the Sierra Nevada.”
Dr. Cahill’s report showed that the average PM concentrations made at Davis City Hall over the December through February test period was 9.0 ug/m3 while that simultaneously measured by the California Air Resources Board at their 13th and T St. monitoring site in downtown Sacramento averaged 8.8 ug/m3 over the test period. He also presented a graph showing the PM readings at both sites as shown below.
Dr. Cahill attributed this relative equivalency to the fact that Davis receives westerly winds carrying particulate matter passing over Sacramento that originated in the Sierra foothills where wood burning is very prevalent. He then presented a meteorological model of how such air flows occurred over a specific one-day period last winter.
Presentation by Alan Pryor of Yolo Clean Air
Dr. Cahill’s presentation was followed by a presentation by Alan Pryor of Yolo Clean Air who reviewed Dr. Cahill’s report and submitted 8 pages of technical comments to the NRC. Mr. Pryor has often been at odds with Dr. Cahill during the past year over the need for wood burning restrictions in Davis and his PowerPoint presentation made a number of points seemingly overlooked in the Cahill report.
Firstly, Mr. Pryor pointed out that if Davis air is now functionally equivalent to Sacramento air in terms of particulate matter, this represents a very ominous deterioration of air quality in Davis. He indicated that almost exactly 1 year earlier Dr. Cahill wrote an Op-Ed in the Enterprise and sent a letter to the Council opposing any wood burning restrictions in Davis because ““the PM2.5 in Davis is about ½ that of Sacramento”. Dr. Cahill had then claimed that the comparatively cleaner air in Davis obviated the need for mandatory restrictions such as had already been imposed in Sacramento.
Pryor then stated that if PM air quality in Davis air is now equivalent to downtown Sacramento and only one year earlier it was claimed that it was only half that of Sacramento, then PM in Davis air had to get twice as bad or Sacramento air had to have had PM reduced by 50% – or a combination of the two.
Pryor then pointed out that since regional air patterns have not substantially changed over the past 6-8 years, he believe this comparative change is probably due to the simple fact that Sacramento has implemented restrictive wood burning strategies over the past two years to reduce wood smoke pollution while Davis has continued, possibly even increased, unfettered burning. In other words, Pryor claimed the comparative deterioration of air quality in Davis compared to Sacramento is much more likely due to distinctly different approaches to wood smoke pollution control taken in Sacramento vs. Davis and not otherwise due to general regional air quality conditions as Cahill suggested.
Mr. .Pryor then presented a table of air PM measurements that were taken by CARB at their UC Davis monitoring station simultaneous with the study done by Dr. Cahill at City Hall. This data showed an average PM2.5 concentration from November through January last winter that averaged 14.1 ug/m3 – or about 55% higher than that reported by Dr. Cahill for the monitoring he did at the Davis City Hall site. Pryor claimed that this may be due to the fact that the test site selected by Cahill and staff was in a very protected area behind City Hall that was shielded on all sides by two story buildings or large mature trees. He claimed this may have resulted in reporting lower values than seen elsewhere in the city with more free flowing air. He also pointed out the average measurements at the UCD site gathered by CARB were 31% higher than those recorded the previous year at the same site. He also showed that in January, after the decision on wood burning restrictions was deferred by the Council, that PM measurements increased by almost 80% from the previous January. Pryor claimed this was a clear indication of increased wood burning in the city.
Pryor then stated that regional air transport from east to west cannot explain why Davis PM2.5 is now equivalent to Sacramento because, as stated by Dr. Cahill in his own words in his letter to the Council last year, “the wind blew from the town to the west sites only 4% of all hours in December.” Pryor also presented data that showed that westerly winds also only occurred about 5% of the time last winter. Pryor then claimed that if it were just regional air patterns determining the PM2.5 concentrations in Davis air, then Davis PM2.5 should have also been equivalent to Sacramento in past years too instead of only being 50% as much as Sacramento as Cahill had earlier pointed out.
Next Pryor took at aim at Dr. Cahill’s summary of the mobile monitoring results for which Dr. Cahill reported, Local impacts were hard to ascertain, with only one documented heavy smoke impact of a short duration from an extremely nearby source….”. Pryor claimed that the real purpose of the study was to try to obtain information on hot spots of wood smoke throughout Davis due to the nearest neighbor impacts of wood burning. He claimed it did not really matter whether Davis PM was higher or lower than Sacramento because these PM concentrations could be completely dwarfed by wood smoke generated by a nearby upwind burning neighbor. He then represented a summary of his previously submitted computer modeling results to the NRC
Pryor did say that the one offsite measurement of Davis air that was provided by Dr Cahill reported a PM concentration of 1,500 ug/m3 obtained under conditions in which smoke was visibly apparent. Pryor pointed out that this was about 160 times as high as the average PM concentration reported by Cahill for City Hall (at 9.0 ug/m3) and claimed this was proof that localized, low wind conditions can exist in which extremely PM accumulations can be exist that present an immediate danger to nearby neighbors. He said it was exactly these kinds of conditions that the proposed NRC wood burning ordinance was designed to protect people from exposure.
Mr. Pryor then pointed out that there were many other indicators of declining air quality in Davis including the American Lung Association’s grade of “D” that they gave Yolo Co PM air quality in their State of the Air report for 2009. He also pointed out that Davis and other parts of Yolo and Solano Co. had recently been designated as “non-attainment” with respect to PM pollution levels by the EPA because of the supposed impact its PM air quality has on adjoining regions.
Finally Pryor then began a spirited defense of the proposed ordinance by going over many of the stated public objections to the ordinance (e.g. it is too draconian, the science does not support it, it is unenforceable, etc) and pointed out what he claims were the fallacious basis of those objections. He also noted that he estimated that 90% of the population from Bakersfield to Chico and covering the entire Bay Area were now under some type of mandatory wood burning restrictions. (Note: Readers can click on the Vanguard link below to review Pryor’s PowerPoint presentation and his comments in their entirety – click here). Dr. Cahill’s report is available on the city’s website as an agenda attachment for last Monday’s NRC meeting).
NRC Debate and Approval of a Revised Proposed Wood Burning Ordinance.- Following the presentations of Dr. Cahill and Mr. Pryor, the NRC began to debate the issue of revising the then existing proposed ordinance or sending it back to the Council intact.
Commissioner Adrienne Kandel made comments pointing out that if the object of the proposed ordinance is to treat all wood burners fairly then the proposed ordinance should try to allow operation of any type of wood burning appliance or fireplace as long as the specified conditions under which they operate result in equivalent maximum emissions and resultant ground level concentrations of wood smoke. She said that Pryor’s own modeling work showed that even the use of open hearth fireplaces could be safely done under some higher wind conditions. She advocated that any proposed ordinance sent back to the Council should reflect this fact rather than banning the use of open hearth fireplaces completely.
Planning Commission Liaison Kris Kordana then pointed out that the NRC would never have all the answers to all the questions about wood burning and how it is disbursed and thus would never have the perfect ordinance. But he said he thought that everyone was in general agreement that wood smoke is potentially harmful especially to children, seniors, and susceptible populations with respiratory impairments. Given that, he said that he thinks the NRC should make an informed decision and formulate the best ordinance possible given the knowledge that they have and revisit the issue in the future if more compelling information is made available about ambient PM levels, how it is disbursed in the environment, or the toxicity of wood smoke.
Finally after almost 4 ½ hours, the NRC constructed language for a revised proposed ordinance to forward to the Council. There were three main changes between this proposed ordinance and that previously submitted to the Council last year.
1) Permissible hours of operation of EPA-Approved Phase II stoves and pellet stoves on “Allowable Burn Days” were increased from 6 to 12 hours.
2) Open Hearth and non-EPA-approved wood stoves or inserts would be allowed to be used for up to 6 hours per day on days when wind speeds were sufficiently high.
3) Only seasoned hardwoods and manufactured pellets would be allowed to be burned in any wood-burning appliance.
The final vote was 5-1 in favor of the ordinance. The lone dissenting vote was cast by Commissioner Doug Fetterly who explained his opposition by stating that he did not believe anyone in Davis would put up with an old smog-belching car running for hours in front of their neighbors’ homes. He said he thought that open hearth fireplaces were similarly polluting and he was opposed to their use under any conditions. Thus, he said, he was not in favor of revising the ordinance as amended by Commissioner Kandel to allow for their use – albeit under limited conditions.
The full text of the Proposed Ordinance approved by the NRC follows:
The NRC has the responsibility to ensure that all Davis residents have clean air to breath. We therefore recommend that the Davis City Council adopt this proposed regulation which allows wood burning when the negative health impacts are minimized.
In order to protect public health, the NRC proposes the following ordinance providing for the allowable use of wood-burning appliances and open hearth fireplaces for home heating purposes. The purpose of the ordinance is to improve air quality when regional pollution and local meteorological conditions create conditions where even small amounts of wood smoke can cause locally intense exposures to harmful and toxic emissions. These emissions can be particularly harmful to children, the elderly, and other sensitive populations. This ordinance provides a two-tiered system that allows for roughly equivalent total emissions for wood burning appliances, open hearth fireplaces and other non-compliant wood burning appliances. This ordinance allows for wood burning when it is least harmful.
a) Wood burning in approved appliances will be allowed on days designated as “Allowable Burn Days for Approved Appliances” for a maximum of 12 hours per day per residence.
b) Wood burning will be allowed in open hearth fireplaces and other non-compliant wood burning appliances a maximum of 6 hours per day per residence on “Allowable Burn Days for Non-Approved Appliances”.
c) Approved Appliances shall include an EPA Phase II wood stove or pellet stove which is rated at 7.5 grams per hour or less.
d) Allowable Burn Days for Approved Appliances shall be days when the forecasted average regional PM 2.5 concentration is 25 ug/m3 or lower and a forecasted average wind speed from 6 PM to midnight is 5 mph or greater.
e) Allowable Burn Days for Non-Approved Appliances shall be days when the forecasted average regional PM 2.5 concentration is 25 ug/m3 or lower and a forecasted average wind speed from 6 PM to midnight is 12.5 mph or greater.
f) Beginning March 1, 2010, a one-time permit shall be required to demonstrate compliance with this regulation and for law enforcement and educational purposes.
g) The above regulations do not apply for temporary breakdowns of central heating systems and power outages.
h) Only burning of seasoned dry hardwood is allowed.
i) The ordinance shall provide for annual review of this ordinance to assess the impacts of this ordinance, changes in regional air pollution conditions, and to review and approve new technologies.
j) This proposed ordinance does not pertain to any appliances fueled by natural gas or propane and/or designed and exclusively used for cooking purposes.
This kind of thing needs to be done at the state level, IMHO.
Well… good for the NRC to propose something (vs. punting it down the road). But better for Doug Fetterly… the proposed ordinance is simply weak weak weak. NRC is not upholding its obligation as stated in the first sentence of the proposed ordinance. NRC… step up; prevent more filth from polluting our air and ban burning in open hearth fireplaces!
We are not in a developing country and do not need to kill (or even damage the health of) our neighbors in order to heat our homes (or provide that romantic glow and nice crackle).
A weak ordinance like this would be nice on the state level (thus allowing for wood burning fires in low density rural areas). But in Davis, a neighborhood setting, the ordinance should be much stricter.
Why would people in Davis burn wood while knowing that it sickens and kills their neighbors? What on earth is wrong with them? If they are that selfish, then Davis or ANY civilized town needs an ordinance that protects the weaker citizens from their neighbors. And to twist science to justify folks’ selfishness sounds way too familiar since the horrendous Bush years. If the Council has any guts at all they’ll ignore the NRC’s spinelessness. By the way, what’s wrong with people signing their names to these comments – chicken?
Sherrill – do you ever drive a car, use something that is powered by electricity or spray an aerosol? Until you live a life that doesn’t have any negative impact on the environment, your shrill criticisms are ring hollow. Many of these folks are simply trying to heat their homes with a renewable resource – its not the worst thing in the world.
“its not the worst thing in the world”
That’s a pretty low standard you set. So by that definition, we shouldn’t worry about crimes such as rape, since that’s hardly the worst thing in the world you can do to another person. I’m being flippant here, but come on, so we should only worry about the worst things in the world?
Wood burning to people with allergy and other respiratory problems is among the worst things in the world.
And while wood is somewhat renewable (as long as you aren’t clear cutting old growth forests), it also releases particulate matter and CO2 into the atmosphere. I’m sure there are better and less selfish ways to heat your home and get your jollies.