SACRAMENTO METROPOLITAN 

AIR QUALITY MANAGEMENT DISTRICT

For Agenda of September 24, 2009

To: Board of Directors 

Sacramento Metropolitan Air Quality Management District 

From: Larry Greene, 

Executive Director/Air Pollution Control Officer 

Subject: Adopt a Resolution Approving Amendments to Rule 421 – Mandatory Episodic 

Curtailment of Wood and Other Solid Fuel Burning 

Recommendations 

1. Determine that the amendment of Rule 421 is exempt from the California 

Environmental Quality Act (CEQA); 

2. Decide whether to include one or more of the options in the proposed 

amendment; and 

3. Approve the attached resolution amending Rule 421. 

Executive Summary 

Staff recommends amending the wintertime fireplace and wood stove burning restrictions to 

help achieve federal health standards and minimize further regulatory burdens on other 

industries. The staff recommendation maintains the exemption for EPA certified devices and 

pellet stoves on some days. The Board may consider several alternatives that provide greater 

health protections than staff's recommendation, including one alternative that eliminates that 

exemption. Staff considered extensive public comments obtained at five workshops held in July 

as well as meetings with stakeholders, and recommends a modest increase in the number of No 

Burn days in light of economic concerns expressed by residents that burn wood for heat. 

Rule 421, Mandatory Episodic Curtailment of Wood and Other Solid Fuel Burning currently 

contains the following key provisions. 

• Prohibits burning wood, pellets, and other solid fuels (e.g. corn) when fine particle 

pollution (PM2.5) concentrations are forecast to exceed the federal health standard 

during the months of November through February. 

• Prohibits burning when PM2.5 concentrations are predicted to exceed 35 μg/m3, except 

burning in EPA certified wood stoves or pellet stoves (called a Stage 1 day.) 

• Prohibits all burning when PM2.5 concentrations are forecast to exceed 40 μg/m3

 (called 

a Stage 2 day.) 

• The rule does not apply to natural gas or propane fireplaces and stoves. 

• The rule exempts burning that is the sole source of heat, or in situations when not 

burning would be a financial hardship to a resident. 

Staff's recommendation would change the thresholds noted above for calling Stage 1 and Stage 

2 days to 31 and 35 μg/m3, respectively. This change would add 5 No Burn days on average 

and each additional Stage 1 No Burn day there would be an estimated 10% improvement in air 
Board Memo 

Rule 421 

September 24, 2009, Page 2 

quality, and a 23% improvement on additional Stage 2 days. Staff’s recommendation would 

have resulted in historically a reduction of 3 days over the health standards on average. 

These rule changes are important because: 

1. Sacramento does not meet state or federal health standards for fine particle air 

pollution (PM2.5). 

2. Fine particulate pollution is linked to serious adverse health effects, including 

aggravated asthma, heart attacks, and premature death in people with heart or lung 

disease. New health studies have increased the concern about wood smoke health 

impacts, particularly impacts on children. 

3. The largest single source of Sacramento's wintertime PM2.5 emissions is wood, 

pellet and other solid fuel burning in fireplaces, inserts, wood and pellet stoves. 

Studies showed that Rule 421 has been very successful in improving air quality. The Sonoma 

Technology, Inc. (STI) study found up to a 23% improvement in PM2.5 air quality from Rule 

421. Aurora Research Group found that 92% of the respondents were aware of burning 

restrictions. Although the public response to the rule and air quality improvements were 

significant, they are not sufficient to meet the health standards. There were 20 unhealthful days 

during the winter 2008/2009 season. 

Other options for modifying the rule that are included for Board consideration are: 

Optional threshold changes (μg/m3) 

 Current rule Recommended 

Change Option A Option B 

Voluntary threshold 25 25 20 or 25 20 

Stage 1 threshold 35 31 Eliminated 25 

Stage 2 threshold 40 35 30 30 

Changes in Number of No Burn Days 

 Stage 1 Stage 2 Stage 1 Stage 2 Single Stage Stage 1 Stage 2 

Average # of No 

Burn days 7 16 5 23 31 13 31 

Average additional # 

of No Burn days – 5 8 21 

Average # of 

voluntary No Burn 

days 

22 171 33 @ 20 μg/m3 

13 @ 25 μg/m3 20 

Contingency Option – Automatically reduce threshold to 20 μg/m3 if Sacramento does not meet federal 

health standards by 2014 or 2019 deadlines – Average of 64 No Burn days (41 additional No Burn days) 

Staff is not recommending Option A, Option B or the Contingency Option. 

 

1

 The number of days is lower than the current rule, even though the threshold has not changed, 

because some of the previous voluntary days would become mandatory No Burn days. 
Board Memo 

Rule 421 

September 24, 2009, Page 3 

Attachments 

The table below identifies the attachments to this memo. 

Item Attachment

Board Resolution A 

Proposed Rule 421 and Options B 

May 2009 Board Letter 

 Attachment A – Aurora Survey Report 

 Attachment B – STI Phase I Report 

C 

Staff Report 

 Appendix A – 40727.2 Matrix 

 Appendix B – List of Changes to Rule 

 Appendix C – Aurora Survey Report 

 Appendix D – STI Phase I Report 

 Appendix E – Emissions Calculations 

 Appendix F – Workshop Notice Comments and Responses

 Appendix G – ERG Socioeconomic Evaluation 

D 

Comments and Responses from Public Hearing Notice E

STI Transport Analysis F 

Evidence of Public Notice G 

Background and Health Effects

Particulate matter (PM) is a mixture of very small liquid droplets and solid particles. Adverse 

health effects are linked to particles that are less than 10 microns in diameter (PM10), and fine 

particles that are less than 2.5 microns in diameter (PM2.5). The District is currently designated 

as a nonattainment area for the state and federal2

 health standards for PM10 and for the state 

health standard for PM2.5. In addition, the District will be nonattainment for the federal 2006 

24-hour PM2.5 National Ambient Air Quality Standard (NAAQS) when formal designations are 

published later this year. 

Wood smoke also contains other air contaminants including volatile organic compounds (VOCs) 

and nitrogen oxides (NOx), which are precursors to aerosol forms of PM2.5, and toxic and/or 

cancer-causing substances, such as benzene, formaldehyde and benzo-a-pyrene, a polycyclic 

aromatic hydrocarbon (PAH). In addition, black carbon is a component of wood smoke. 

 

2

 Based on 1998-2000 monitoring data, EPA made a finding (February 15, 2002 Federal Register, 

Volume 67, Number 32, Page 7082 et seq.) that Sacramento County attained the federal ambient 

PM10 standard by the applicable December 31, 2000 attainment deadline. Note that this EPA finding 

did not redesignate the Sacramento District to attainment. 
Board Memo 

Rule 421 

September 24, 2009, Page 4 

According to the U.S. Environmental Protection Agency (EPA), health studies have linked 

exposure to particulate matter, especially fine particles, to several significant health problems, 

including: 

• increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty 

breathing; 

• decreased lung function; 

• aggravated asthma; 

• development of chronic bronchitis; 

• irregular heartbeat; 

• nonfatal heart attacks; and 

• premature death in people with heart or lung disease. 

Exposure to particulate matter pollution can cause coughing, wheezing, and decreased lung 

function even in otherwise healthy children and adults. Postmenopausal women, because they 

are more susceptible to heart and vascular disease, are more susceptible to cardiovascular 

health impacts from fine particulates. EPA estimates that thousands of elderly people die 

prematurely each year from exposure to fine particles. In addition, a recent study (Dominici et 

al., 2006) of the correlation between PM2.5 concentrations and hospital admission rates 

concluded that short-term exposure to PM2.5 increases the risk of hospitalization for 

cardiovascular and respiratory diseases. 

The California Air Resources Board (CARB) heard the results of several studies3

 that showed 

smoke from wood fires aggravates lung and heart disease and increases the number of hospital 

admissions. The research results indicate exposure to wood smoke may reduce lung function 

and reduce the blood’s ability to clot properly. In addition, wood smoke exposure may also 

increase substances in the body that lead to cardiovascular and pulmonary inflammation. The 

studies also found that up to 70 percent of smoke from chimneys can re-enter a home or 

neighboring residences. 

The research further found that children are more likely to be harmed by PM2.5 and wood 

smoke than adults because their respiratory systems are still developing, they breather more air 

per pound of body weight, and they are more active outdoors. Recent studies have concluded 

that children breathing PM2.5 and wood smoke are likely to experience: 

• more coughing and wheezing, 

• reduced lung function if they have asthma4

, 

• permanent reduction in lung air capacity5

, 

• ten percent increased hospital admissions from respiratory problems6

, and 

• decreases in memory function and scores on intelligence tests7. 

 

3

 California Air Resources Board, The potential health impacts of residential wood burning, Jan. 2009,

http://www.arb.ca.gov/research/health/healthup/Jan09.pdf 

4

 Allen R et al 2008, Changes in lung function and airway inflammation among asthmatic children 

residing in wood smoke-impacted urban area. Inhal Toxicol. 20(4):423-433 

5

 Gauderman WJ et al, The Effect of Air Pollution on Lung Development from 10 to 18 Years of Age. N 

Engl J Med 351;11:1057-1063, Sept 2004 

6

 Anderson ZJ et al, Ambient particle source apportionment and daily hospital admissions among 

children and elderly in Copenhagen. J Expos Sci Environ Epidemiol. 17(7):625-636. 

7

 Suglia F et al, Association of Black Carbon with Cognition among Children in a Prospective Birth Cohort 

Study. American Journal of Epidemiology. 2008:167:280-286 
Board Memo 

Rule 421 

September 24, 2009, Page 5 

In 2008, CARB updated their studies of mortality effects from elevated PM2.5 concentrations. 

They now estimate that in the Sacramento Metropolitan Area, up to 600 premature deaths 

would be avoided at an economic benefit of over $3 billion per year if the region met the state 

and federal annual PM2.5 standards. 

In addition, studies have shown that with less air pollution, people will walk and bicycle more for 

recreation and transportation8. People who live in an area more conducive to walking have 

been shown to walk more, weigh less, and have lower blood pressure9,10. Rule 421 has the 

potential to increase walking of residents by decreasing wood burning emissions. Furthermore, 

the analysis of Rule 421 effectiveness has shown the largest air quality improvement occurred 

in the early evening, when people are more likely to be active or commuting home from work or 

school. Staff has received feedback from some members of the public that the reduction in 

wood smoke has made it nicer to walk and has reduced health concerns from breathing wood 

smoke. 

State and Federal Requirements 

The District is currently designated as a nonattainment area for the state PM10 and PM2.5 

standards and the District does not meet federal health standards for fine particle air pollution 

(PM2.5). On December 22, 2008, the EPA Administrator signed rules designating the 

Sacramento area as nonattainment for the federal 24-hour PM2.5 health standard of 35 μg/m3

. 

The designations are under review by the new administration and are expected to be published 

in the coming months. Attainment plans are expected to be due in late 2012 and the attainment 

deadline will be 2014, but may be extended to 2019 if properly justified to EPA. 

The plan must include transportation conformity budgets and control measures. Transportation 

conformity budgets will require that future transportation projects stay within the specified 

emission levels to meet attainment and progress goals. Failure to submit a plan can result in 

withholding of federal transportation project approvals and funding. 

The District's strategy to improve particulate matter air quality includes a three-pronged 

approach to reducing emissions from wood burning: providing financial incentives, regulating 

new wood burning installations, and reducing burning from existing fireplaces and wood stoves. 

The District provides financial incentives to remove or replace existing fireplaces and dirty wood 

stoves. Rule 417 prohibits installing new fireplaces and dirty wood burning devices. The last 

prong was the adoption of Rule 421, Mandatory Episodic Curtailment of Wood and Other Solid 

Fuel Burning, in 2007. Residents and businesses that take advantage of the financial incentives 

to install gaseous fuel burning devices are exempt from wood burning regulations11

. 

Based on 2006-2008 PM2.5 data, PM2.5 concentrations have increased, likely due to weather 

influences. It is likely that the current Rule 421 alone will not be enough to attain the federal 

health standard before the plan is due. Strengthening Rule 421 by lowering the thresholds will 

 

8 Pikora T et al, Developing a framework for assessment of the environmental determinants of walking 

and cycling. Social Science & Medicine. 56 (2003): 1693-1703 

9 Frank LD et al, Many Pathways from Land Use to Health. Journal of the American Planning 

Association. 72 (2006): 75-87

10 Fuzhong L et al, Built environment and changes in blood pressure in middle aged and older adults. 

Preventive medicine. 48(2009)237-241. 

11 The District has given away $766,600 to incentivize the changeout of 2128 devices. Over 1900 of the 

devices were fireplaces and 75% of the replacement devices are gaseous fueled. 
Board Memo 

Rule 421 

September 24, 2009, Page 6 

help to reduce PM2.5 concentrations during winter months. These changes combined with 

state and local measures may be sufficient to meet federal health standards. 

The federal Clean Air Act requires attainment plans to include Best Available Control Measures 

(BACM). If we cannot show we have reached attainment with the current version of Rule 421, 

then other measures will need to be considered such as controls on agriculture, fugitive dust, 

and more stringent controls on PM control devices. 

Because Sacramento County is designated as a nonattainment area for the PM standards, the 

District was required by state law, Senate Bill (SB) 656, to adopt a plan for implementing 

feasible, cost effective measures to attain the state and federal PM standards. Rule 421 

implemented measures in the SB656 plan. Other wood smoke and other plan measures were 

postponed pending evaluation of the effectiveness of Rule 421 in reducing particulate matter 

concentrations. Without strengthening Rule 421, the postponed measures, rejected measures, 

and measures contained in other district’s control plans are more likely to be needed to meet 

state health standards. 

May Board Letter Discussion 

On May 28, 2009, Staff presented an informational item to the Board. Staff presented the 

results of two studies that showed that Rule 421 has been very successful in improving air 

quality. The Sonoma Technology, Inc. (STI) study found a 10% improvement on a Stage 1 No 

Burn day and a 23% improvement on a Stage 2 No Burn day in PM2.5 air quality from Rule 421. 

Aurora Research Group found that 92% of the respondents were aware of burning restrictions. 

Staff used the Aurora Survey to determine compliance rates for Stage 1 and Stage 2 No Burn 

days. 

Some Board members expressed concern that having too many No Burn days will reduce 

compliance especially if the change is too drastic. Others expressed a desire to increase public 

education, emphasize the benefits of changing out old devices, and requested staff make a 

recommendation on the rule options. Finally, at least one Board member requested a map of 

the violations issued last year. This map can be found on the following page. 

The May Board Letter is included in Attachment C. 
Board Memo 

Rule 421 

September 24, 2009, Page 7 

Rule 421 Violation Map 
Board Memo 

Rule 421 

September 24, 2009, Page 8 

New Information 

This section presents results from two new studies were completed after the May Board 

hearing, both studies suggest that Rule 421 provides important air quality benefits in 

Sacramento County. The studies and their results are discussed briefly here. They confirm that 

Rule 421 restrictions in rural areas provide important health benefits. In addition, this section 

discusses new emissions inventory information which is an important consideration regarding 

whether to maintain the Stage 1 exemption for EPA certified and pellet stoves. 

Phase II Transport Analysis and Results

During the 2007 adoption of Rule 421, Board members requested a study of the impacts of 

transported air pollutants, particularly from rural Sacramento County, on peak PM2.5 

concentrations and whether it is necessary to include those areas in the Rule 421 program. The 

language of Rule 421 permits partial County forecasts, but to-date the no burn forecasts include 

all Sacramento County residents. 

Sonoma Technologies Inc. (STI) recently completed a new study that quantified the relative 

contributions of wood smoke from rural Sacramento County and other counties. This study 

showed that the area responsible for the most significant portion of wood smoke emissions 

impacting our worst air quality site, near Del Paso Manor Elementary School, is from urban 

Sacramento County. However, rural Sacramento County emissions contribute significantly (26 

percent) to pollution levels in Elk Grove, which exceed health standards. 

STI's analysis quantified the contribution of residential wood smoke emissions in surrounding 

areas to primary PM2.5 concentrations at the air monitoring stations at Del Paso Manor 

Elementary School, Elk Grove at Bruceville Road, and Folsom City Hall. Of these three sites, 

only the Del Paso Manor monitoring station has a Federal Reference Monitor (FRM) used to 

determine attainment with federal air quality standards. The Del Paso Manor monitoring station 

exceeds the federal health standards. The Bruceville and Folsom monitoring stations measure 

PM2.5 concentrations using Beta Attenuation Monitors (BAM). Both sites record air quality 

concentrations that do no meet the federal health standards. STI also evaluated Sacramento 

County impacts at two locations in neighboring counties, Roseville, and Davis. 

STI conducted two different analyses, called: Comprehensive Air Quality Model (MM5/CAMx) 

and Transported Emissions Assessment Kit (TEAK). Both models use spatially and temporally 

resolved meteorological data and wood smoke emissions data to estimate daily contributions of 

primary wood smoke emissions from urban and rural Sacramento County and surrounding 

counties to PM2.5 concentrations at several receptor sites. Neither model accounted for the 

nitrogen oxide or volatile organic compound emissions from wood smoke that also contribute to 

PM2.5 pollution problems. 

• Comprehensive Air Quality Model (MM5/CAMx)

MM5/CAMx modeling used information gathered by the $20 million Central California 

Air Quality Studies (CCAQS) during December 15, 2000 through January 9, 2001. 

This model is a state-of-the-art tool developed by UC Davis and other academic 

researchers that was used by CARB and the San Joaquin Valley air district in their 

2008 PM2.5 State Implementation Plan. This air quality model allowed STI to 

analyze sub county region impacts and account for wet and dry particle deposition 

and turbulent diffusion. 
Board Memo 

Rule 421 

September 24, 2009, Page 9 

• Transported Emissions Assessment Kit (TEAK) model

TEAK modeling traces monitored air quality backwards in time and space to identify 

the source and relative contribution from other counties. The model was run for 

2000/2001 to allow corroboration and comparison with the MM5/CAMx model, and 

for the 2007/2008 and 2008/2009 CBYB seasons to allow evaluation of additional, 

more recent, weather conditions. The key limitation of this model is that it does not 

account for particle deposition or diffusion which both can reduce PM2.5 

concentrations. Therefore, the results from the TEAK model are expected to be 

slightly higher than MM5/CAMx. 

The results indicate that primary PM2.5 concentrations from wood smoke at monitors within 

Sacramento County are mostly attributable to wood smoke sources in Sacramento County. STI 

found that at all three Sacramento County locations, wood smoke from urban Sacramento 

County is the largest contributor, and No Burn days are an effective way to reduce PM2.5. 

Urban Sacramento contributes 79% at Del Paso Manor, 26% at Bruceville and 53% at Folsom. 

In addition, at the Bruceville monitor, the rural parts of Sacramento County are the second 

largest contributor (26%) of wood smoke primary PM2.5 and No Burn days in rural Sacramento 

County has a substantial effect on reducing PM2.5 at Bruceville. The study also showed that 

Sacramento County impacts air quality in adjacent counties, 9 to 35% at Davis, and 17 to 54% 

in Roseville. The study showed that there was almost no impact from adjacent districts at the 

Sacramento site monitoring the worst air quality, Del Paso Manor, but a modest to significant 

impact on the sites closer to county boundaries, Folsom and Bruceville. Because neither of 

these sites are used for federal attainment purposes, the studies suggest that wood smoke from 

adjacent counties is unlikely to prevent the Del Paso Manor station from attaining the standards. 

However, wood smoke from other counties does impact public health of citizens that reside near 

county borders. 

The Phase II STI report12 is included in Attachment F. 

New Emission Inventory

New CARB emission inventory information shows the contribution for fireplaces has significantly 

decreased based on a revised fireplace emission factor, percent of fireplaces used, amount of 

wood used and accounting for supplemental heating or aesthetic fireplace use. 

A common misperception is that EPA certified and pellet stoves are better for air quality than 

fireplaces. However, recent CARB emissions inventory updates show that emissions from EPA 

certified devices are generally higher than fireplaces because they are used more frequently 

and for a longer duration to provide heat. Therefore, to the extent that maintaining the Stage 1 

program encourages replacement of fireplaces with EPA certified and pellet stoves, that would 

not result in an air quality benefit. The District does not provide financial incentives for 

replacements or retrofits of fireplaces with EPA certified and pellet stoves or inserts. 

 

12 STI conducted analyses for several different emissions inventory because of proposed changes 

discussed in the emissions impacts section below. The results presented in this Board letter are based

on analysis results that used the updated CARB emissions inventory presented in Appendix B of the 

Phase II STI report. 
Board Memo 

Rule 421 

September 24, 2009, Page 10 

Device Type 

PM2.5 per 

device per year 

(lbs/year) 

Fireplace – 

 Aesthetic 

 Heating 

3 

24 

Uncertified wood stove 

Catalytic wood stove 

Non-Catalytic wood stove 

71 

47 

34 

Uncertified wood insert 

Catalytic wood insert 

Non-Catalytic wood insert 

57 

38 

27 

Pellet stove 6 

Summary of Proposed Amendments 

Although the public response to the rule and air quality improvements were significant, they are 

not sufficient to meet the health standards. There were 20 unhealthful air quality days during the 

winter 2008/2009 season. Therefore, staff is recommending modest changes to increase the 

number of no burn days to provide additional health protection. The proposed change in no 

burn thresholds are based on two new pieces of information, estimated forecast underprediction, and the actual air quality benefits of the Stage 1 no burn days. 

Recommended Change - Reduce the Stage 1 threshold from 35μg/m3 to 31 μg/m3 to account 

for the potential underprediction in air quality forecasts. Reduce the Stage 2 threshold from 40 

μg/m3

 to 35 μg/m3 to account for the actual benefits that occur on Stage 1 No Burn days. The 

recommended change is expected to result in 5 more No Burn days. On each additional Stage 

1 No Burn day there would be an estimated 10% improvement in air quality, and a 23% 

improvement on additional Stage 2 days. The recommended change would have resulted in 

historically a reduction of 3 days over the health standards on average. 

Of the options considered, the Recommended Change provides the smallest increase in the 

number of No Burn days. The Board may want to consider increasing the number of No Burn 

days even more. Staff evaluated the following options. 

Option A – Change to a single-stage program, thereby eliminating the Stage 1 exemption for 

EPA certified wood stoves and pellet stoves. Set the No Burn threshold to 30 μg/m3 and 

either maintain the voluntary threshold at 25 μg/m3 or reduce it to 20 μg/m3. These 

thresholds are consistent with the San Joaquin Valley APCD program, and are more likely to 

meet Clean Air Act requirements for reasonably available control measures. Option A is 

expected to result in 8 more No Burn days. 

This was the staff recommendation presented at the public workshops. However, many 

comments at the workshops expressed concern that eliminating a two-stage program, with 

its exemption for EPA certified devices and pellet stoves on Stage 1 days, would reduce the 

incentive for people to switch to cleaner devices and also be unfair to those who have 

already invested in cleaner devices. Note that although, recent information shows that EPA 

certified and pellet stoves are not beneficial because owners of those devices burn more 
Board Memo 

Rule 421 

September 24, 2009, Page 11 

wood, the public perception is that they are cleaner than fireplaces. This is an area where 

public education regarding this new information may be needed. 

Option B - Maintain the Stage 1 exemption but lower the threshold more; set the Stage 1 

threshold to 25 μg/m3

 and the Stage 2 threshold to 30 μg/m3 to be consistent with the San 

Joaquin Valley No Burn threshold. Reduce the voluntary threshold to 20 μg/m3

. Option B is 

expected to result in 21 additional No Burn days. 

Contingency Option - Include a provision to automatically change to a single-stage program 

eliminating the Stage 1 exemption for EPA certified and pellet devices with a reduced 

threshold of 20 μg/m3 if Sacramento does not meet the federal health standards by the 

required deadlines, either 2014 or 2019. Using the past 5 years of data, this would result in 

up to approximately 41 additional No Burn days. However, due to uncertainty in the 

effectiveness of future control measures to improve air quality the actual number of days 

would likely be lower. 

In addition, Staff recommends adopting language that clarifies that the intent of the Rule is that 

first-time violators may complete and pass the smoke awareness course. 

Under the staff-recommended option, on each additional Stage 1 No Burn day there would be 

an estimated 10% improvement in air quality, and a 23% improvement on additional Stage 2 

days. Based on analysis of the actual forecast and observed PM2.5 concentrations for 2007-

2009 periods, if the proposed thresholds had been in place, Sacramento County would have 

had the following additional avoided exceedances per year: 

• Staff Recommendation – 3 fewer exceedances than the current rule 

• Option A – 4 fewer exceedances than the current rule 

• Option B – 5 fewer exceedances than the current rule 

The number of avoided exceedance days will likely be higher in the future because, historically, 

on our very worst days, a 23% air quality improvement hasn’t been enough to attain the 

standards. But as air quality improves, due to emission reductions from other sources, 23% 

may be enough and the actual number of days avoided will be higher. 

Impact on Businesses and Public 

Rule 421 applies to anyone who burns wood, pellets or any other solid fuel in open fires or solid 

fuel burning devices (fireplaces, wood or pellet stoves or inserts), and commercial fireplace 

installations in locations such as hotels and restaurants. 

Impacts analyzed included: 1) reduced wood and pellet sales by retailers, 2) increased fuel 

costs to consumers/businesses if wood retailers raise prices to maintain revenue, and 3) 

changes in heating costs from reduced supplemental heat from wood or pellets. Businesses 

with solid fuel burning devices other than those used for cooking would have a cost savings 

from reduced wood use, because they generally burn wood for aesthetic purposes. An increase 

in the number of No Burn days will increase the cost savings. Staff does not have information to 

quantify the impact, if any, to these businesses due to the loss of ambience. 

The impact on wood retailers is due to reduced wood burning by the public, and therefore, the 

amount of wood sold by retailers. The estimated value of the wood products not purchased 

over the entire winter season due to reduced burning is $577,781; $1,137,064; $1,620,987; and 
Board Memo 

Rule 421 

September 24, 2009, Page 12 

$4,211,867 for the Recommended Change, Option A, Option B and the Contingency Option, 

respectively. 

In the socioeconomic analysis for these amendments, Appendix G of the Staff Report 

(Attachment D), worst case impacts to businesses were estimated using two different 

assumptions. The first impact assessment used an assumption that all of the lost revenue from 

wood sales due to the additional No Burn days falls upon independent wood dealers and that 

dealers could not increase prices. In other words, no wood is sold in grocery stores or other 

retail outlets. This would result in the following potential maximum impacts to revenues and jobs 

for independent wood dealers: 

• Recommended Change: 4.6% loss in revenue, 2.8 jobs lost 

• Option A: 8.7% loss in revenue, 5.3 jobs lost 

• Option B: 14% loss in revenue, 8.5 jobs lost 

• Contingency Option: 34.1% loss in revenue, 20.6 jobs lost 

In the second analysis wood retailers raise prices to maintain income while selling less fuel. 

The following potential maximum price increase and impacts to consumers may occur: 

• Recommended Change: 4.6% price increase, $11-$18 increased cost per household 

per season 

• Option A: 8.7% price increase, $22-$35 increased cost per household per season 

• Option B: 14% price increase, $35-$56 increased cost per household per season 

• Contingency Option: 34.1% price increase, $84-$136 increased cost per household 

per season 

The costs noted above represent 0.02% to 0.24% of the Sacramento County 2007 median 

income. 

The third impact assessment used an assumption that all of the lost revenue falls upon large 

retail stores. Under this assumption, intended to estimate the maximum impact on retail stores, 

the percentage loss in revenue is negligible under all of the options and no job losses are 

expected. Since wood is sold by both independent wood dealers and retailers, the actual job 

losses would likely be lower than estimated. 

Many of the residents affected by the rule burn wood for ambiance and would experience cost 

savings from reduced wood use. For those who use wood as their primary or supplemental 

heat source, burning wood only provides a clear cost savings if wood is obtained without any 

costs associated with cutting and transporting the wood. For those who purchase their wood, 

there will be a shift in costs from wood to an alternate source for heat. The data in the table 

below show that it costs less per unit of heat delivered to use natural gas than to use wood, and 

that electric heating is only slightly more expensive than burning wood. The average cost of 

heating a typical home with a certified wood stove for 30 days is $139 and $172 of a pellet 

stove, while the cost is $153 for electricity and $88 for natural gas. Anecdotal information from 

comments during public workshops suggests that some consumers may have reduced heating 

costs from using wood or pellets as a supplemental heat source. Reported cost savings may 

result from personal comfort choices and/or because wood burning may heat main living areas 

while other rooms remain cooler than if the home’s alternative heat source were used, resulting 

in a net reduction in heat delivered. 
Board Memo 

Rule 421 

September 24, 2009, Page 13 

District Impacts 

Compliance and enforcement will remain the same as the current rule. Approximately 1.2 FTE 

was required to administer the 10 Stage 1 days and 28 Stage 2 days experienced in the 

2008/2009 season. Using a ratio of the options to last season, and keeping in mind that last 

season was an above average year for the number of No Burn days, the estimated Staff 

resources for the additional No Burn days for the enforcement/compliance effort are 0.16 FTE, 

0.25 FTE, 0.66 FTE, or 0.82 FTE for the Recommended Change, Option A, Option B, or 

Contingency respectively, specifically for the following: 

1) Surveillance by inspection Staff on the additional No Burn days for at least 1 hour per 

day per inspection Staff member (or a total of 8 hours on weekends/holidays). 

2) Responding to the increase in reported burning or smoke complaints from the public due 

to the additional No Burn days. 

3) Handling of the increase in Notice of Violations (NOVs) from the additional No Burn 

days. 

Emission Impacts 

The California Air Resources Board is responsible for preparing the wood burning emission 

inventory for Sacramento County. Wood smoke is the single largest source of directly emitted 

PM2.5, 49% as reported by CARB’s 2005 California Emission Forecast System (CEFS) 

wintertime PM2.5 emissions inventory for Sacramento County. The 2005 emissions inventory is 

8.30 tons on an average winter day from wood burning in Sacramento County. 

The residential wood smoke combustion emissions inventory is being re-evaluated by CARB in 

preparation for upcoming federal PM2.5 plans. Several relevant surveys have been conducted 

since CARB last modified the methodology. 

 

13 Socioeconomic Impact Analysis for SMAQMD Rule 421 Amendments, ERG, 2009 

Heating Device Thermal Efficiency Fuel Cost per mmBtu 

of Heat Delivered 

Fireplace 7% $206.23 

Certified Wood Stove 63% $22.91 

Pellet Stove 76% $28.29 

Propane Fireplace 75% $34.24 

Natural Gas Fireplace 75% $14.54 

Electric Fireplace >99% $25.23 

Gas Central Heat & Air 80% $13.63 

Electric Central Heat & Air 100% $25.23 

Propane Central Heat & Air 80% $32.10 

Note: 

1. Used as primary source of heat 

2. PG&E rates for natural gas (Winter 2009) 

3. SMUD rates for electricity (Winter 2009) 

4. Average cost of cord of wood13 = $269, average cost of pellets13 = $344/ton, and Cost of propane = 

$2.31/gallon 
Board Memo 

Rule 421 

September 24, 2009, Page 14 

For detailed emission inventory calculations see Appendix E, Emissions Calculations, of the 

Staff Report (Attachment D). 

The emissions reductions were calculated using results from the 2009 Aurora Survey of burning 

behavior during the Rule 421 No Burn program. The table below summarizes the revised 

CARB methodology estimates the daily average PM2.5 emissions from wood burning in 

Sacramento County during November – February and the estimated emission reductions from 

Stage 1 and Stage 2 days. Detailed calculations and data sources are presented in Appendix E 

of the Staff report (Attachment D). 

Reductions (tons/day) 

Pollutant 

Nov. – Feb. 

Daily Average Emissions 

(tons/day) 

Stage 1 Day Stage 2 Day 

PM10 11.95 5.17 8.37 

PM2.5 11.47 4.97 8.03 

NOx 1.39 0.59 0.76 

CO 78.5 22.3 54.8 

VOC 35.2 18.9 24.6 

 Note: Each option has the same reduction per No Burn day but the number of No 

Burn days differs in each option. 

Environmental Review and Compliance 

Rule 421 was created as part of the response to the requirements of Senate Bill 656 that the 

District implement cost-effective control measures for particulate matter emissions. Staff finds 

that the proposed rule is exempt from the California Environmental Quality Act as an action by a 

regulatory agency for protection of the environment (Class 8 Categorical Exemption, Section 

15308 State CEQA Guidelines) and because it can be seen with certainty that there is no 

possibility that the activity in question may have a significant adverse effect on the environment 

(Section 15061(b) (3), State CEQA Guidelines). 

 

California Public Resources Code (Section 21159) requires an environmental analysis of the 

reasonably foreseeable methods of compliance. Staff anticipates that users of solid fuel burning 

devices will comply with No Burn day restrictions by not burning for ambience and, where wood 

burning provides supplemental heat, by using alternative sources such as natural gas or 

electricity. The use of these alternative fuels will result in a decrease in the emissions of 

particulate matter and other air pollutants, including greenhouse gasses, with a corresponding 

improvement in air quality and public health. 

There has been some debate as to whether the burning of wood should be considered “carbon 

neutral,” because even though carbon dioxide is released from the burning of wood, carbon 

dioxide was absorbed by the living trees. Burning simply returns that carbon dioxide to the 

atmosphere, thus the term “neutral.” However, the term “carbon neutral” is something of a 

misnomer, because other greenhouse gasses, including methane and nitrous oxide (much more 

potent greenhouse gasses than carbon dioxide) and black carbon particles (another global 

warming pollutant), are released when wood is burned, while only the carbon dioxide is 

absorbed by living trees. Carbon neutrality, at least with respect to carbon dioxide emissions, 

depends on a number of factors, including whether the wood has been harvested from a 
Board Memo 

Rule 421 

September 24, 2009, Page 15 

sustainable resource. Both BAAQMD14 and SJVAPCD15 have found that a large percentage of 

the firewood being burned comes from nonsustainable activities. In particular, there has been a 

loss in the acreage of oak woodlands in Northern California, including the foothills on the 

eastern side of the Central Valley, attributable to urban growth, firewood harvesting, and land 

clearing for vineyards and developments. Similar activities have been conducted in Sacramento 

County and the surrounding areas. It may take as long as 200 years for young trees to 

approach the carbon storage capacity of old growth forests. 

Based on the foregoing, staff believes wood burning in Sacramento County is not carbon 

neutral. Nevertheless, Staff has examined the net effect on greenhouse gas emissions under 

two scenarios: 1) the burning of wood is not carbon neutral, and 2) the burning of wood is 

carbon neutral with respect to carbon dioxide. The analysis also considered greenhouse gas 

emissions associated with electricity due to fuel burned at electrical power plants. The following 

table shows the results of this analysis, based on equal heat outputs using natural gas or 

electricity rather than wood combustion on No Burn days. 

GHG Emissions (metric tons/yr CO2 Equiv.) 

Heat Source Recommended 

Change Option A Option B Contingency Option 

Wood 6,249 11,891 19,070 46,557 

Wood – Carbon (CO2) neutral 552 1,051 1,686 4,116 

Natural Gas 1,270 2,418 3,877 9,466 

Electricity – Only CO2 1,418 2,698 4,326 10,561 

As shown in the table, if wood burning is not carbon neutral, there is a net decrease in 

greenhouse gas emissions from using natural gas or electricity instead of wood on No Burn 

days. Even assuming, wood burning is carbon (CO2) neutral, the increase in greenhouse gas 

emissions from using the replacement fuels on No Burn days is marginal. Under the 

Recommended Option, assuming that wood burning is carbon (CO2) neutral, and wood is 

replaced by electricity on No Burn days, there is a worst case net increase in greenhouse gas 

emissions of 866 metric tons per year of CO2 equivalents, which represents only 0.005% of the 

greenhouse gas emission inventory for Sacramento County and 0.0002% of the California 

inventory. 

Even in the worst case (Contingency Option, using electricity instead of wood), the increase in 

greenhouse gas emissions represents only 0.04% of the greenhouse gas emission inventory for 

Sacramento County and 0.001% of the California inventory. 

Staff has concluded that no significant environmental impacts will be caused by compliance with 

the proposed rule. 

Cost Effectiveness 

The cost effectiveness of the amendments can be calculated by using the cost (lost sales for 

wood suppliers) and the emissions reductions discussed earlier. The Recommended Change 

 

14 BAAQMD, Draft Environmental Impact Report for the Bay Area Air Quality Management District’s 

Proposed Regulation 6, Rule 3 Wood-Burning Devices, May 2008 

15 SJVAPCD, Final Staff Report Proposed Amendments to Rule 4901, October 2008 
Board Memo 

Rule 421 

September 24, 2009, Page 16 

cost effectiveness is estimated to be $3.14 per pound of PM2.5 for a Stage 1 No Burn day and 

$5.32 per pound of PM2.5 for a Stage 2 No Burn day. To put these costs into perspective, it is 

useful to compare the cost effectiveness for other District rules. District Rule 417, Wood 

Burning Appliances, cost $4.19/lb of PM2.5 in today’s dollar. It should be noted that most of the 

District’s existing rules are for controlling ozone precursors, usually VOC or NOx. Rule 421 also 

achieves NOx reductions. The cost effectiveness of this rule is $2.80 - $4.86 per pound of NOx 

+ PM2.5. The 2005 amendments to District Rule 411, NOx from Boilers, Process Heaters and 

Steam Generators cost $13.90/lb of NOx. The cost effectiveness of the gasoline dispensing 

regulations (Rule 449, Transfer of Gasoline into Vehicle Fuel Tanks; 12/17/1991 rule 

amendments) is at the higher end of the cost effectiveness range, costing $17/lb of VOC in 

today's dollars. Rule 452, Can Coating (8/21/1990 rule amendments), is at the low end of the 

range at a cost of $1/lb of VOC in today's dollars.

Public Outreach 

Staff conducted five public workshops throughout Sacramento County between July 13th and 

July 22nd. Each workshop started with a structured presentation of the four options with time 

available for questions and comments. The workshops were held in downtown Sacramento, 

Carmichael, Folsom, Galt and at the District office. The noticing for these public meetings 

included: 

• Letters to all elected officials in Sacramento County 

• Ad in the Our Region section of the Sacramento Bee

• Notices to newspapers across Sacramento County 

• Notices to radio stations across the region 

• Letters to homeowner associations 

• Notice on the District’s Web site 

• Notices by mail and e-mail to the District’s list of parties interested in rule development. 

Staff received comments and questions at the workshops, through the mail, e-mail and at 

stakeholder meetings. Comments and responses are listed in Appendix F of the Staff report 

(Attachment D). In addition, Staff conducted stakeholder meetings with HBPA and various 

retailers, Sacramento Area Realtors, and Breathe California. 

A notice for the September 24, 2009 public hearing was published in the Sacramento Bee, Our 

Region Section on August 24, 2009. The notice was also mailed to attendees of the public 

workshop, affected sources, and persons who have requested rulemaking notices. 

Public Comments 

Staff received over 200 comments on the proposal presented at the July workshops. Staff’s 

responses to these comments are included in the Staff report. A large number of comments 

received at the workshops and via email were on the initial staff recommendation, which was to 

eliminate the Stage 1 exemption for certified devices. Many comments were from owners or 
Board Memo 

Rule 421 

September 24, 2009, Page 17 

local wood stove retailers of certified or pellet devices, and the Hearth Patio and Barbeque 

Association who opposed eliminating the current two-stage program, with its limited exemption 

for certified and pellet devices on Stage 1 No Burn days. After consideration of these 

comments, Staff changed the recommendation to maintain the limited exemption on Stage 1 

days for EPA certified and pellet stoves/inserts. 

Other comments supported Staff’s workshop Recommended Change and supported the more 

stringent Option B. A few comments, predominantly from hearth product manufacturers or their 

association, offered an option of having the District adopt a no visible smoke rule, where visible 

smoke emissions are prohibited during the entire winter season. Additionally, some comments 

suggested that we work to eliminate burning in all fireplaces. 

An option to prohibit visible smoke for the entire winter season would affect all 155,649 

fireplaces, 14,310 uncertified wood stoves and 44,184 uncertified wood inserts as well as tens 

of thousands of certified devices which are not capable (either by design or user operation) of 

burning without visible smoke on every day, not just on the bad air quality days. One 

manufacturer claims to have a catalytic retrofit device that reduces visible smoke from 

fireplaces. The cost of replacing or retrofitting all fireplaces and uncertified wood stoves/inserts 

is estimated to be up to $400 million or more. In addition, this approach would burden our 

limited staff resources by requiring enforcement on every day of the wood burning season 

instead of just No Burn days. Additionally, a total ban on wood burning would increase the 

likelihood of decreasing compliance rates. Therefore staff does not recommend establishing a 

comprehensive winter time smoke ban at this time. 

A comment from Duraflame received after this public hearing notice was issued suggested 1) 

eliminating the voluntary curtailment, 2) making the rule a single stage No Burn program 

eliminating the limited exemption for EPA certified devices and pellet devices, and 3) setting the 

No Burn threshold at 35 μg/m3

. The voluntary curtailment program provides a mechanism to 

inform the public that PM2.5 concentrations are elevated, but not to the extent that a mandatory 

curtailment is warranted. Many members of the public will choose not to burn as a result of this 

message resulting in an improvement in air quality. Messaging for the District’s Check Before 

You Burn program clearly differentiates between voluntary requests and mandatory 

requirements 

A significant number of comments/questions were about how the District and the CBYB 

program function. The remaining comments were about emissions inventory, transport of fine 

particle pollution from surrounding areas, economic impacts, number of No Burn days, 

meteorology and other rules and regulations of the District.