### Partnership for Policy Integrity info@pfpi.net **Air pollution from biomass energy (updated April 20 11)** 

**Despite the frequent depiction of biomass as “clean ” energy, data from air permit applications and rea**  **l smokestack tests demonstrate quite clearly that bio**  **mass is a heavily polluting technology.**

**Burning wood and other biological materials for ene rgy emits as much or more pollution than burning**  **fossil fuels, including coal. Emissions are functio n of the fuel type, combustion temperature, and pol**  **lution controls, but in PFPI’s analysis of air pollution p**  **ermits in 7 states we have found that biomass burne rs are**  **always more polluting than natural gas and are simi lar to coal - admittedly better for some pollutants**  **like sulfur and mercury, but the same or worse for parti**  **culates and nitrogen oxides. Being similar to coal hardly qualifies as clean, green energy.** 

**Biomass electricity generation facilities are major air polluters, and in many cases will significantl**  **y worsen air quality in the communities and regions where th**  **ey are constructed. Yet in most cases biomass gets a**  **break because it is (inaccurately) considered renewable and carbon neutral** 

**.**

**The We Energies facility in Rothschild, Wisconsin i s an example of regulators allowing a heavily pollu**  **ting biomass facility to proceed precisely because it is**  **classified as renewable and counts toward the stat e’s**  **renewable energy goals. According to the facility’s air permit, the new biomass burner, located at the**  **Domtar paper mill, will be a huge air polluter**  **. It will almost certainly throw the region into vi olation of air**  **pollution health standards for particulate matter, which the US EPA considers a lethal form of air pol**  **lution that causes ten of thousands of premature deaths ac**  **ross the country each year and increases the incidence of asthma attacks in children; and it wil**  **l emit 6 times as much carbon per unit of electrici ty**  **generated as a natural gas burner being constructed on the same site. State regulators could have**  **required cleaner burning fuels at the plant, but de clined to do so specifically because the plant is**  **producing “renewable” energy.**

**Sanctioning and subsidizing major new sources of po tentially lethal air pollution is not what anyone h**  **ad in mind when establishing renewable energy standards.**  **Regulators should take a clear-eyed, fact-based approach to evaluating whether or not these facilit**  **ies should operate given the significant air pollut ion that**  **they cause. In our view, biomass burners should no t be allowed to operate until they can show that th**  **ey are dramatically cleaner then all fossil fuel alter**  **natives, if they are to qualify as renewable energy under**  **state policies.**



### What kind of pollution does a biomass burner emit?
**Burning biomass emits large amounts of pollutants, just like burning other solid fuels such as coal.**  **Burning organic material emits particulate matter ( PM), nitrogen oxides (NOx), carbon monoxide (CO),**  **sulfur dioxide (SO 2**  **), lead, mercury, and other hazardous air pollutant s (HAPs).** 

**Hazardous air pollutants are a group of 187 toxics**  **that according to EPA**  **“are known or suspected to cause cancer or other serious health effects, such**  **as reproductive effects or birth defects, or advers e**  **environmental effects”. EPA has recently released t he newest**  **National Air Toxics Assessment , which** 
**characterizes emissions and ambient air concentrati ons of toxics around the country.** 

**The HAPs emitted in the greatest quantities by burn ing biomass include the organic HAPs styrene,**  **acrolein, and formaldehyde, and the acid gases hydr ofluoric acid and hydrochloric acid,. Biomass burne**  **rs commonly emit ten tons or more of the acid gases an**  **d from one to five tons of organics each year. Even “clean wood” – that is, forestry-derived wood, as o**  **pposed to construction and demolition debris – emit s**  **these chemicals when burned. Burning clean wood als o emits non-negligible amounts of heavy metals.**  **Burning “urban wood” – a friendly term for construc tion and demolition debris (CDD) – significantly**  **increases emissions of arsenic, chromium, copper, l ead, and mercury, as well as dioxins/furans and** 

### Partnership for Policy Integrity info@pfpi.net **pentachlorophenol (PCPs). Biomass developers someti mes claim that sorting out the contaminated wood**  **from CDD produces a “clean” and safe fuel stream, b ut it is virtually impossible (and not cost effecti**  **ve) to remove the contaminated wood using visual inspectio**  **n and hand sorting. Even one or two percent contaminated wood can lead to significant emissions**  **of metals when this material is burned (see a letter**  **documenting the inadequacy of CDD sorting for a pro posed CDD-burner in Massachusetts, and a**  **letter from the MA Department of Environmental Health**  **expressing concerns about emissions of metals and other air toxics in the environmental justice commu**  **nity of Springfield, MA, where childhood asthma rat es**  **and incidence of high blood lead levels are already twice the State average).** 



### How much pollution do biomass-burning facilities em **it?**
**Most biomass plants do not use the most effective p ollution controls, and small-scale biomass burners,**  **like those being installed to provide heat to schoo ls around the country, typically only have minimal**  **controls. Utility-scale biomass plants emit tens to hundreds of tons of particulates, nitrogen oxides,**  **carbon monoxide, and and hazardous air pollutants each yea**  **r.**

**Emissions are typically expressed in air permits as pounds of pollution per million btu of heat input**  **(as fuel). The problem with this approach is that it hi**  **des differences in efficiency that exist between fa cilities.**  **Converting these rates so they are expressed in ter ms of emissions per unit energy delivered to the gr**  **id is a more accurate way of evaluating the impact of**  **different technologies and fuels.**

**To give an idea of how much pollution a biomass pla nt can produce, here are emissions numbers from**  **the air permit and application documents for the pr oposed 100 MW Gainesville Renewable Energy Center**  **(GREC) in Florida, contrasted with air permit**  **numbers from the much larger Pioneer Valley Energy Center**  **(PVEC), a 431 MW gas and diesel plant proposed in W estfield, Massachusetts. The emissions rate for**  **the biomass plant far exceeds that for the gas plan t for criteria air pollutants, HAPs, and carbon dio**  **xide. Yet biomass proponents insist on calling biomass a**  **“clean” fuel.**

**Here are some more data on pollution emissions, sho wing how different the emissions are when the**  **same burner is firing different fuels. The followin g table is from the air permit application for the**  **Hu Honua facility in Hawaii, an old coal burner that is bein**  **g retrofitted to burn wood and biodiesel. Pollution emissions from the boiler (here expressed as pounds**  **per million btu) are significantly greater when**
**biomass is used as a fuel:** 

### The 100 MW Gainesville Renewable
**Energy biomass plant will emit**
**dramatically more pollution than a 431 MW gas/diesel plant in Massachusetts,** 

**both as total tons, and as lb per MWh GREC: 100** 

**MW biomass:**
**tons per year GREC** 

**biomass**

**lb/MWh PVEC: 431 MW** 

**nat gas/diesel:**
**tons per year PVEC: nat** 

**gas/diesel**

**lb/ MWh** GREC rate as %

PVEC rate
**Nitrogen oxides 416.4**  0.95 **91.9** 0.05 1953%

**Carbon monoxide 713.8**  1.63 **59** 0.03 5214%

**Particulate matter 249.8**  0.57 **49.1** 0.03 2193%

**Sulfur dioxide 243.9**  0.56 **16.7** 0.01 6295%

**Volatile organic compounds 77.3**  0.18 **23.8** 0.01 1400%

**Hazardous air pollutants 24.7**  0.06 **5.1** 0.003 2087%

**Carbon dioxide 1,232,225**  2,813 **1,432,825** 759 371%

### Partnership for Policy Integrity info@pfpi.net **Emissions data for school-sized boilers also highli ght the difference between biomass and other fuels.**  **The Wyalusing School District in Pennsylvania appli ed for air permits for a new biomass burner, and a** 
**new oil burner. Emissions rates for the biomass bur ner are higher for PM, NOx, and CO, but are lower f**  **or VOCs and SO**  **2 (differences in the total tons emitted are to some**  **extent also a function of the different amounts of time the burners are projected to be use**  **d.). All rates are in units of lb/mmbtu.**



### Control of particulate matter
**Particulate matter emissions are implicated in a wi de range of health impacts, from asthma and heart**  **disease to diabetes. Even when the most sophisticat ed emissions controls are used, biomass burning**  **produces large amounts of the fine particulate matt er that penetrates deeply into the lungs. There are**  **a number of technologies for reducing emissions of fi**  **lterable particulate matter, but three main technol ogies**  **are often used with biomass burners. None is truly effective at removing fine particulates.** 

**Cyclone and multicyclone systems rely on centrifuga l force to spin particulates out of the flue gas.**  **Cyclonic systems are not effective at removing the fine particulate matter that has the greatest impac**  **t on air quality and health, although**  **according to EPA , some high efficiency systems show removal of 60 t**  **o 95% for PM**  **10 and 20 to 70% for PM**  **2.5 . Cyclone systems are often found as the sole means**  **of PM control**

**at small-scale burners like those installed in scho ols around the country. Emissions data from the**  **Wyalusing air permit, above, show that a typical sc hool burner may emit around 9 tons of particulate**  

### Wyalusing Area School District - emissions from ne w biomass and oil burners

PM rate PM tons NOx rate NOx tons CO rate CO tons VOC rat e VOC tons SO 2 rate SO 2 tons

Oil burner 0.03 0.29 0.12 1.18 0.04 0.39 0.025 0.25 0.21 2.06

Wood burner 0.22 8.68 0.182 7.18 0.163 6.48 0.004 0.16 0.002 0.08

### Partnership for Policy Integrity info@pfpi.net **matter a year. These emissions occur from low stack s and impinge directly on children in playgrounds**  **and as they sit in class.**

**Electrostatic precipitators (ESPs) use an electric field to remove particles from the flue stream. The**  **y can remove up to 99% of fine particles (PM**  **2.5 ) from the flue gas, although their efficacy in rem**  **oving ultrafine particles is not well quantified. ESPs are expensiv**  **e and are not typically installed in building-scale**

**biomass burners.**

**Additionally, with all these control technologies, we are talking about removal of filterable particul**  **ate matter, which is just one component of total partic**  **ulate matter. The other component is known as “condensable” particulate matter, and it consists o**  **f the fine and ultra-fine particles derived from su lfur,**  **nitrogen, and VOC emissions that condense in the at mosphere after the flue gas has left the stack.**  **Because the actual formation of condensable particu late matter depends both on emissions and**  **atmospheric chemistry, it is not well characterized , therefore most air permitting agencies make some**  **assumption about the ratio of condensable to filter able particulate matter when they are writing a per**  **mit for the amount of total particulate matter (filtera**  **ble plus condensable) emitted by a facility. Such assumptions may or may not be well-justified.** 

**Fabric filters or baghouses are generally considere d the most effective means of emissions control for**  **filterable particulates. They can show control effi ciencies upwards of 99%. They are installed at some**  **mid-sized facilities and many utility-scale facilit ies.** 

**The amount of particulate matter emitted from a bio mass burner is highly sensitive to small difference**  **s in control efficiency. The following table shows how m**  **uch filterable PM 10**  **is emitted in four different**
**scenarios. Note that the first scenario combusts a much smaller amount of wood than the other three –**  **this is meant to represent the operation, for insta nce, of a biomass burner at a mill that is generati**  **ng power and heat for its own operation. Despite the**  **relatively small amount of wood burned, the average control efficiency of 80% for the multiclone system**  **means that PM emissions are quite high.**

**The three other scenarios (2-4) show a larger amoun t of wood, such as would be burned at a utility-sca**  **le biomass plant supplying power to the grid, and thre**  **e different levels of control efficiency. Even a fe w**  **tenths of a percent of control efficiency make a la rge difference to the total tons of PM emitted. Thi**  **s is also relevant to control of heavy metals, which are**  **generally assumed to be emitted as a component of particulate matter, with the exception of mercury,**  **which is emitted as a vapor.**



### Emissions from small-scale biomass burning compared **to wood stove emissions**
**Biomass proponents will sometimes claim that biomas s burners “emit less pollution than a woodstove”.**  **For well controlled facilities, per unit wood burne d**  **, this is true, because baghouses and other polluti on**  **control equipment reduce the amount of pollution em itted. However, the sheer amount of material burned**  

### Control of filterable particulate matter

Scenario Control

technology control

efficiency uncontrolled

PM10 (lb/mmbtu) tons wood tons PM
(uncontrolled) PM rate

(lb/mmbtu) tons PM

emitted

1 Multiclone 80.0% 6.5 26,000 799

1.3 160

2 ESP 99.0% 6.5 400,000 12,298

0.065 123

3 Baghouse 99.5% 6.5 400,000 12,298

0.0325 61

4 Baghouse 99.9% 6.5 400,000 12,298

0.0065 12

### Partnership for Policy Integrity info@pfpi.net **in a utility-scale facility or even at a medium-siz ed sawmill means that pollution emissions massively** 
**exceed those from a residential wood-burner. And th e emissions are no less harmful. The size distribut**  **ion of the particulate matter that escapes control by a**  **baghouse or ESP is shifted toward the smallest siz e**  **fractions – and in the case of particulates (not to mention all the other pollutants) what you can’t s**  **ee can definately can hurt you.** 

**But what about a school-sized facility, compared to a woodstove? Estimates of the amount of particulat**  **e matter emitted by a residential woodstove vary by a**  **factor of ten or more, but assuming an average PM emission rate of 30 grams per hour (a value between**  **old woodstoves and EPA-certified woodstoves), and assuming 6 months of stove operation at 18 hours pe**  **r day, the average woodstove emits about 214 lb of particulate matter over the heating season. Assumin**  **g 6 months of operation for a school sized boiler o f**  **about 4 mmbtu, such a facility might emit around 1. 9 tons of particulate matter. This would then be ab**  **out the equivalent of PM emissions from about 18 reside**  **ntial woodstoves.**



### How do emissions from biomass plants compare with c **oal plants?**
**Different plants have different emissions rates dep ending the fuel burned, control equipment installed** 

**, and how well the facility is operated. The EPA “**  **BACT Clearinghouse ” (BACT means “Best Available**  **Control Technology”) contains permitted emission ra tes for fossil fuel and biomass plants around the**  **country. While the database is not comprehensive, a nd does not necessarily show the best controlled**  **plants, it provides a representative sample of some of the lower emitting plants around the country. T**  **he following table shows a range of emission rates for**  **existing coal plants and biomass plants from the BACT Clearinghouse, as well as the Ryegate biomass**  **plant in Vermont, a recently re-permitted existing plant, and rates from a variety of permits for prop**  **osed biomass plants around the country.**

**The data show that emission rates for NOx at some c oal plants are lower than at many biomass plants. I**  **f the typical difference in plant efficiency were tak**  **en into account and the rates expressed on a per MW h**  **basis, instead of a heat input basis, the differenc e would be even greater. Similarly, there is a high**  **degree of overlap for CO and PM emission rates between coa**  **l plants and biomass plants. Sulfur dioxide (SO 2**  **, or SOx) is the pollutant where emission rates are clea**  **rly higher for coal than biomass. The BACT Clearinghouse does not include data on VOC emission**  **s.**

**Some coal plants achieve lower emissions rates than are allowed in their permits. For instance, the**  **Mount Tom coal plant in Holyoke, MA, has turned in stack test data that indicate the plant’s SO**  **2 emission**  **rate is 0.066 lb/mmbtu, lower than any rate reporte d in the BACT clearinghouse database. The data also** 

**indicate a total PM 10**  **emission rate of 0.0059 lb/mmbtu, meaning that yea rly emissions of PM10 from this**  **147 MW facility are around 39 tons per year if the facility operates continuously. In contrast, the 35**  **MW Palmer Renewable Energy biomass plant to be built i**  **n nearby Springfield, MA, will have a total PM10**
**emission rate of 0.019 lb/mmbtu and will emit 42.4 tons of PM**  **10 per year.** 



### Does co-firing biomass reduce emissions?
**Co-firing biomass is sometimes seen as a way to red uce emissions at coal plants, particularly of sulfu**  **r dioxide, because wood generally has a lower sulfur**  **content than coal (an exception is construction and** 

### boilers > 250 mmbtu/hr, emissions as lb/mmbtu of he at input

Existing coal Existing biomass Ryegate biomass Propose d biomass

NOx 0.07 (several) 0.065, 0.1 - 0.15 0.15 0.06 - 0.15

CO 0.1, 0.13, 0.135 0.1, 0.19, 0.24, 0.3 0.3 0.0365 - 0.176

PM10 fil 0.01, 0.012 0.02, 0.025, 0.03 0.017 0.008 - 0.015

SOx 0.1, 0.14, 0.245 0.02 0.019 0.012 - 0.042

### Partnership for Policy Integrity info@pfpi.net **demolition debris, which can have relatively high s ulfur content probably due in some part to**  **contamination by gypsum wallboard waste).**

**While replacing a significant amount of coal with w ood would reduce sulfur emissions, the effect on ot**  **her pollutants is not straightforward. Test-firing data**  **from the Killen coal plant in Ohio, which proposes to co**  **fire 5% wood by heat content (amounting to over 8% by mass) shows that adding even this small amount**  **of wood to the fuel stream produces dramatic increa ses in emissions of carbon monoxide and hazardous**  **air pollutants.**

**The following data are from the Killen plant’s tech nical support document for the air permit applicati**  **on to**
**co-fire biomass. Metals emissions show some small i ncreases and decreases with addition of biomass,**  **and there are small percentage decreases in emissio ns of hydrochloric acid and hydrofluoric acid, but**  **the key thing to notice is that replacing 5% of the boi**  **ler’s heat input with biomass produces no improveme nt**  **in criteria pollutant emissions with the exception of a small decrease in lead emissions. It does, how**  **ever produce large percentage increases in carbon monoxi**  **de, volatile organic compounds (VOCs), and certain organic hazardous air pollutants (HAPs).** 

**“PTE” means “potential to emit”, which standardizes emissions by assuming the boiler operates at full**  **capacity 365 days of the year. All emissions are ex pressed as tons per year (“tpy”).** 

### Partnership for Policy Integrity info@pfpi.net **The Killen plant will co-fire about 180,000 tons of wood per year, or the equivalent of the wood that**  **could be produced by clearcutting about 2,050 acres of Oh**  **io’s forests per year (we use U.S. Forest Service**

**data to estimate standing biomass). Increasing the amou**  **nt of wood co-fired to a level that would actually decrease sulfur emissions would require significant**  **ly increasing forest harvesting, and would meanwhil e**  **have unacceptably large effects on emissions of oth er pollutants. Co-firing biomass should not be allo**  **wed as a way for coal plants to avoid installing modern**  **pollution control equipment, which is vastly more effective at reducing sulfur emissions than changes**  **in fuel.**



### Biomass and the Clean Air Act
**Large-scale biomass burners are subject to Clean Ai r Act regulation and permitting like other emitters** 

**, with one crucial difference. The Clean Air Act requ**  **ires “Prevention of Significant Deterioration” (PSD )**  **review for air quality when a new “major source” fa cility is built or when an existing facility underg**  **oes major modification in an area that is either classe**  **d as in attainment, or unclassifiable, with regard to the**  **National Ambient Air Quality Standards (NAAQS). PS D review**  **requires installation of the Best Available**  **Control Technology (BACT, a standard that takes int o consideration the cost of air pollution controls,**  **and allows rejection of some controls as too expensive)**  **, air quality analysis, an additional impacts analy sis,**  **and public involvement. However, while the threshol d for triggering PSD review for a fossil-fueled boi**  **ler 250 mmbtu/hr or greater is emission of 100 tons of**  **a criteria pollutant, the threshold for triggering PSD**  **review for a biomass burning facility is 250 tons. This means that a facility burning biomass can emit**  **two and a half times the amount of pollution that a fos**  **sil-fueled facility emits before it is subjected to a similar**  **level of scrutiny and emissions control.**

**Biomass, Hazardous Air Pollutants, and EPA’s “boile r rule”**  **To reduce the amount of hazardous air pollutants em itted by commercial and industrial boilers, EPA set**  **s limits for certain pollutants under the “boiler rul**  **e”, which is part of the Clean Air Act. The boiler rule is**  **especially significant for biomass burners because although the boiler rule regulates fossil-fueled bo**  **ilers only up to 25 MW in size, it regulates all biomass**  **boilers, no matter how large.**

**The boiler rule sets the maximum allowable emission limits for just five pollutants, although there ar**  **e 187 different HAPs recognized by EPA. Setting emission**  **s limits for each one would be difficult, so instea d,**  **EPA regulates the majority of pollutants by dividin g them into classes and using proxies to estimate h**  **ow well their emissions are controlled. Under the boil**  **er rule, particulate matter (PM) serves as a proxy for**  **metallic HAPs like arsenic and lead, and carbon mon oxide (CO) is regulated as a proxy for organic HAPs**  **like formaldehyde and acrolein. The boiler rule reg ulates dioxins/furans, mercury, and hydrochloric ac**  **id (HCl) directly, with HCl also acting as a proxy for**  **other acid gases (like hydrogen fluoride).**

### Partnership for Policy Integrity info@pfpi.net **To control emissions of these pollutants, EPA sets maximum emissions rates for different kinds of boil**  **ers and different fuels. These emission rates are based**  **on the “best performing” (lowest emitting) units t hat**  **already exist. To set emissions rates for existing boilers, EPA essentially averages the best performi**  **ng 12% of boilers, using their emission rates as the s**  **tandard that all existing units are supposed to ach ieve.**  **For new as-yet-unbuilt boilers, EPA expects those t o achieve the same emission rate as the single best**  **performer (lowest emitter) that already exists. Th ese standards are referred to as Maximum Achievable**  **Control Technology (MACT), and are set for coal, bi omass, gas, and other liquid fuels boilers.** 

**EPA further identifies two categories of emission s ources under the boiler rule – “major” and “area”**  **sources. A major source is one which emits 25 tons or more of total HAPs, and 10 tons or more of any**  **single HAP (for biomass, the HAP usually emitted in the greatest quantities is hydrochloric acid, or H**  **Cl).**
**An “area” source is one which emits HAPs below thes e thresholds.** 

**Since the emission rules for major sources are cons iderably more stringent than for area sources, ther**  **e is a great incentive for facilities to characterize th**  **emselves as area sources. Below is a summary of the allowable emission rates for major and area sources**  **. Emission rates for biomass under the major source rule are the same as for coal, except for emission**  **rates of carbon monoxide and dioxins/furans, which are**  **generally higher than for coal.**

**“Boiler rule” emission rates for major sources.**

Subcategory Particulate

Matter Hydrogen

Chloride Mercury

(Hg) Carbon Monoxide
(ppm @3%oxygen) Dioxin/ Furan

(TEQ) (ng/dscm)

Existing –CoalStoker 0.039 0.035 4.6E-06 270 0.003
Existing -Coal Fluidized Bed 0.039 0.035 4.6E-06 82 0.0 02
Existing –Pulverized Coal 0.039 0.035 4.6E-06 160 0.004
Existing –Biomass Stoker/other 0.039 0.035 4.6E-06 490 0.005
Existing -Biomass Fluidized Bed 0.039 0.035 4.6E-06 43 0 0.02 Existing –Biomass Dutch Oven/Suspension Burner 0.03 9 0.035 4.6E-06 470 0.2
Existing –Biomass Fuel Cells 0.039 0.035 4.6E-06 690 4
Existing –Biomass Suspension/Grate 0.039 0.035 4.6E-0 6 3,500 0.2
Existing –Liquid 0.0075 0.00033 3.5E-06 10 4
Existing – Gas2 (OtherProcess Gases) 0.043 0.0017 1.3 E-05 9 0.08
Existing –non-continental liquid 0.0075 0.0003 7.8E-0 7 160 4

New –Coal Stoker 0.0011 0.0022 3.5E-06 6 0.003

New - Coal Fluidized Bed 0.0011 0.0022 3.5E-06 18 0.002

New – Pulverized Coal 0.0011 0.0022 3.5E-06 12 0.003

New – Biomass Stoker 0.0011 0.0022 3.5E-06 160 0.005

New - Biomass Fluidized Bed 0.0011 0.0022 3.5E-06 260 0 .02 New – Biomass Dutch Oven/Suspension Burner 0.0011 0. 0022 3.5E-06 470 0.2

New – Biomass Fuel Cells 0.0011 0.0022 3.5E-06 470 0.00 3 New - Biomass Suspension/Grate 0.0011 0.0022 3.5E-06 1 ,500 0.2
New – Liquid 0.0013 0.0031 2.1E-07 3 0.002
New – Gas 2 (Other ProcessGases) 0.0067 0.0017 7.9E-0 6 3 0.08
New – non-continental liquid 0.0013 0.0032 7.8E-07 51 0 .002

### Partnership for Policy Integrity info@pfpi.net **“Boiler rule” emission rates for “area” sources.**

**From the heat input levels set in the area source r ule, one can see that EPA had in mind regulating**  **relatively small boilers. A 10 mmbtu/hr boiler is r epresentative of the size being installed in some s**  **chool districts, capable of heating more than one buildin**  **g. A 30 mmbtu boiler is the size used by a small sawmill. However, many of the extremely large boile**  **rs being built currently are classified as “area” sources. For instance, the Gainesville Renewable En**  **ergy Center, a 116 MW (gross; 100 MW net) biomass burner with a 1,359 mmbtu boiler, is consid**  **ered to be an “area” source, because the project**
**claims it will emit less than 25 tons of hazardous air pollutants (the exact value in the permit is 24**  **.7 tons of HAPs). This massive project, which will burn wel**  **l over a million tons of wood a year, will therefor e not**  **be held to the stricter standards of the “major” so urce boiler rule.** 

**An important thing to notice about the area source rule is that while EPA set limits for mercury and c**  **arbon monoxide for existing and new coal boilers, to whic**  **h it adds the regulation of PM for new coal boilers**

**, new biomass boilers are only required to meet PM st**  **andards, and there are no standards at all for**  **existing biomass boilers.**



### Information on air pollutants

**Nitrogen dioxide (NO 2**  **) Nitrogen dioxide (NO**  **2 ) is the indicator species for the NOx group of gas**  **es, which includes nitrous acid and nitric acid. It primarily forms when fuels are**  **burned at high temperatures. These acidic gases dir ectly**  **impact respiratory health, and also contribute to f ormation of ozone and condensable particulate matte**  **r. Nationwide, the majority of NO**  **2 is from the transportation sector, but utilities a**  **nd other sources of**

**combustion account for about 34% of total emissions** 

**.**

**As of January 2010, EPA set a new 1-hour standard f or NO**  **2 of 100 ppb in ambient air, and retained the**  **annual average pollution standard of 53 ppb.**

**Ozone** 

### Subcategory Heat Input (mmbtu/hr) Pollutants Emission limit

Coal
Existing coal-fired boiler >= 10 Mercury 0.0000048 lb/ mmbtu
Existing coal-fired boiler >= 10 Carbon monoxide 400 p pm by vol @3% O2

New coal-fired boiler >= 30 Particulate matter 0.03 lb /mmbtu
New coal-fired boiler >= 30 Mercury 0.0000048 lb/mmbtu

New coal-fired boiler >= 30 Carbon monoxide 400 ppm by vol @3% O2

New coal-fired boiler >= 10 and < 30 Particulate matt er 0.42 lb/mmbtu

New coal-fired boiler >= 10 and < 30 Mercury 0.0000048 lb/mmbtu

New coal-fired boiler >= 10 and < 30 Carbon monoxide 4 00 ppm by vol @3% O2

Biomass

New biomass-fired boiler >= 30 Particulate matter 0.03 lb/mmbtu

New biomass-fired boiler >=10 and < 30 Particulate ma tter 0.07 lb/mmbtu

Oil
New oil-fired burner >= 30 Mercury 0.03 lb/mmbtu

New oil-fired burner >= 10 and < 30 Carbon monoxide 0. 03 lb/mmbtu

### Partnership for Policy Integrity info@pfpi.net **A principle component of smog, ground level ozone i s formed when nitrogen oxides (NOx), volatile**  **organic compounds (VOCs), carbon monoxide (CO), and methane react, energized by UV light. The main**  **sources of NOx and VOCs are industrial facilities, electric utilities, motor vehicle exhaust, gasoline**  **vapors, and chemical solvents. As a highly reactive oxidant**  **gas, ozone aggravates the airways, causing respiratory distress and exacerbating asthma. It al**  **so damages vegetation and is increasingly recognize d** 
**as a threat to forest health.**

**EPA has proposed revising**  **its eight-hour standard for ozone from 0.075 ppm t o 0.06 – 0.07 ppm,**  **acknowledging that the ozone standards set in 2008 were not as protective as recommended by EPA’s**  **panel of science advisors, the Clean Air Scientific Advisory Committee (CASAC). EPA has also proposed** 
**a new “ seasonal secondary standard**  **” for ozone exposure that represents cumulative exp osure during**  **peak ozone season.**

**Sulfur dioxide (SO 2**  **) Sulfur dioxide (SO**  **2 ) exposure causes breathing difficulty for people w**  **ith asthma, and is also implicated in regional haze and acid rain formation. A recent EPA**  **risk assessment for SO**  **2 concludes that definite** 

**health risks to asthmatics occur at concentrations significantly lower than the current 24-hour health** 
**standard for SO 2**  **. The document further notes that “over 20 million people in the U.S. have asthma, and**  **therefore, exposure to SO 2**  **likely represents a significant health issue.” The main sources of SO**  **2 are**  **fossil fuel combustion at power plants and industri al facilities. Along with its direct effects, SO**  **2 also**  **contributes to the formation of fine particulate ma tter. EPA concluded that a new SO**  **2 standard with a 1-**  **hour averaging time would be more protective. As of June 2, 2010, EPA strengthened the NAAQS for**  **SO2 by adding a 1-hour standard set at 75 ppb.**

**Particulate matter (PM) Fine particle emissions arise from both direct ash**  **emissions from combustion at energy plants, but also**  **form from emissions of sulfur dioxide, nitrogen oxi des, ammonia, and volatile organic compounds.**  **Particulate air pollution has long been known to be associated with increased cardiopulmonary**  **symptoms, asthma attacks, days lost from work due t o respiratory disease, emergency room visits,**  **hospitalization rates, and mortality. Two size clas ses are recognized in regulatory schemes: PM**  **10 and** 

**PM 2.5**  **, with the numeric value referring to the particle size in microns (a micron is one millionth of a**  **meter). There is no current health standard for PM 10**  **; EPA’s 24-hour and annual exposure standards for**

**PM 2.5**  **are 35 micrograms per cubic meter (μg/m 3**  **) and 15 μg/m 3**  **. EPA’s most recent risk assessment**  **for PM acknowledges that the current standards are insu**  **fficiently protective and indicates that the agency will be lowering the National Ambient Air Quality S**  **tandards (NAAQS) for PM 2.5**  **once more.**

**The classes of particulate matter classed as “black carbon” are implicated in a**  **recent study as having up**  **to 60% of the climate warming effect of CO 2**  **, by both creating “brown clouds” and darkening and thus**  **increasing the heat absorption of snow and ice in p olar regions. Controlling soot emissions and thus**  **lessening albedo effects may thus be an even faster way**  **to mitigate sea ice melting than controlling greenhouse gas emissions. A**  **recent UN report found that controlling black carbon emissions and**  **ozone could dramatically reduce global warming and improv**  **e human health.**

**Lead Lead exposure primarily occurs from paint that has**  **not been remediated. Lead exposure in children is linked to a variety of developmental and neurologic**  **al problems. A recent study**  **concluded that**

**“long-term trends in population exposure to gasolin e lead were found to be remarkably consistent with**  **subsequent changes in violent crime and unwed pregn ancy. Long-term trends in paint and gasoline lead**  **exposure are also strongly associated with subseque nt trends in murder rates going back to 1900. The**  **findings on violent crime and unwed pregnancy are c onsistent with published data describing the**  **relationship between IQ and social behavior. The fi ndings with respect to violent crime are also consi**  **stent with studies indicating that children with higher b**  **one lead tend to display more aggressive and delinq uent** 

### Partnership for Policy Integrity info@pfpi.net **behavior. This analysis demonstrates that widesprea d exposure to lead is likely to have profound**  **implications for a wide array of socially undesirab le outcomes.”** 

**EPA recently dropped the NAAQS for lead from 1.5 μg /m3 to 0.15 μg/m3.** 

**Carbon monoxide (CO) Carbon monoxide is a product of incomplete combusti**  **on that when inhaled, interferes with oxygen absorption in the blood. Emissions of CO from bioma**  **ss boilers generally increase with fuel moisture; “good combustion practices” are frequently cited as**  **the best control for CO emissions. Carbon monoxide can accumulate in closed spaces and could be a prob**  **lem in the vicinity of improperly ventilated**
**combustion sources. Carbon monoxide is treated unde r EPA’s “**  **boiler rule ” as a proxy for certain organic** 
**toxics that are assumed to increase as CO emissions increase.** 

**Hazardous Air Pollutants (HAPs) Hazardous air pollutants (HAPs) is the group name f**  **or 187 compounds which are known to have highly**
**harmful health or environmental effects. The list i ncludes metals like chromium, lead, and mercury, as**  **well as compounds like dioxins (products of combust ion that are widely considered to be among the most**  **toxic chemicals known), benzene (a constituent of g asoline) and formaldehyde. EPA has classified two**  **HAPs as human carcinogens (arsenic and the hexavale nt form of chromium, CrVI) and four as probable**  **human carcinogens (cadmium, lead, dioxins/furans, a nd nickel). All of these HAPs, as well as others, c**  **an be emitted in significant amounts by biomass energy**  **facilities that burn “urban wood” as fuel, which contains lead-painted wood, wood treated with coppe**  **r chromium arsenate, and non-wood materials that exacerbate dioxin/furan formation. Monitoring for t**  **hese pollutants is rare, but emission levels can be high**  **in the vicinity of specific emitters.**

**Arsenic Considered a human carcinogen by EPA, arsenic is hi**  **ghly toxic, and is a principle component of copper chromium-arsenate (CCA) mixture that was used for p**  **ressure-treating lumber. Facilities that proposed t o**  **burn waste wood generally rely on visual sorting te chniques to remove arsenic-containing pressure**  **treated wood from the CDD that it burns. However, s uch detection can be difficult, as noted by the**  **Massachusetts Department of Environmental Protectio n**  **website , which states** 

**“You can usually recognize pressure treated wood by its greenish tint, especially on the cut end, and**  **staple-sized slits that line the wood. However, the greenish tint fades with time, and not all pressur**  **e treated wood has the slits”.** 

**Hexavalent chromium Chromium is also a constituent of pressure-treated**  **wood, and is toxic, particularly in the hexavalent form**  **(CR VI). EPA’s website**  **states: “The respiratory tract is the major target organ for chromium (VI) toxicity,**  **for acute (short-term) and chronic (long-term) inha lation exposures. Shortness of breath, coughing, an**  **d wheezing were reported from a case of acute exposur**  **e to chromium (VI), while perforations and ulcerations of the septum, bronchitis, decreased pu**  **lmonary function, pneumonia, and other respiratory effects have been noted from chronic exposure. Hum**  **an studies have clearly established that inhaled chromium (VI) is a human carcinogen, resulting in a**  **n increased risk of lung cancer. Animal studies ha ve**  **shown hexavalent chromium to cause lung tumors via inhalation exposure.” EPA’s**  **conversion constant for the proportion of total chromium from biomass b**  **urning that is emitted in the hexavalent form is 56 %.** 

**Mercury Mercury is a significant and dangerous contaminant**  **that damages neurological development and other organ functions. It accumulates up food chains, pre**  **senting the greatest threat to humans and fish-eati ng**  **birds like loons. Mercury is transported in the atm osphere but a significant amount from a point sourc**  **e can be deposited nearby, contaminating soils and wa**  **ter bodies. Biomass burning can emit surprisingly high amounts of mercury; for instance, the 21.5 MW**  **Hu Honua facility planned in Hawaii would emit**  **about 10 lb of mercury per year. This emissions rat e is about 0.053 lb/kWh, more than 21 times the** 

### Partnership for Policy Integrity info@pfpi.net **0.0025 lb/kWh emissions rate**  **at the Mount Tom coal plant in Holyoke, Massachuse tts. To be sure, the**  **rate at the coal plant is this low because the faci lity has installed expensive emissions control equi**  **pment – equipment that biomass developers refuse to insta**  **ll because it is not “cost effective”.**

**Dioxins/Furans Dioxins/furans are “persistent, bioaccumulative, an**  **d toxic” (PBT) compounds that are created as by products of chemical manufacturing, and also from c**  **ombustion. Dioxin/furans are known to affect hormone levels and functions, as well as affecting**  **fetal development, the immune system, and reproduction. They are toxic at levels that alread**  **y exist in the environment. EPA states**  **: “Because dioxins are widely distributed throughout the environment i**  **n low concentrations, are persistent and bioaccumulated, most people have detectable levels**  **of dioxins in their tissues. These levels, in the l ow**  **parts per trillion, have accumulated over a lifetim e and will persist for years, even if no additional**  **exposure were to occur. This background exposure is likely to result in an increased risk of cancer an**  **d is uncomfortably close to levels that can cause subtle**  **adverse non-cancer effects in animals and humans.”**