The District ’s Wood Burning Fireplaces And Wood Burning Heaters Rule (Rule 4901) is the most stringent rule in the nation and significantly reduces emissions of direct PM2.5 emissions when and where those reductions are needed most, in urban residential areas during periods of atmospheric stagnation . The Rule collective ly reduces emissions of 5.1 tons

- PM2.5/day. Amendme nts to the rule also lowered the curtailment threshold for non

- re gistered wood burning devices from 30 to 20 μ g/m 3 , significantly lower than any other rule in the nation

. The below discussion provides further clarification and summarizes information included in the staff report prepared during adoption of Rule 4901.

R egistration of Certified Wood Burning Devices Rule 4901 allows certified wood burning devices to be operated during days when the pollutant concentration levels are forecast between 20 μ g/m 3 and 65 μ g/m 3 as long as the device is registered with the Distri ct and operates in accordance with Rule 4901 as follows :

1. Wood burning d evice s must be inspected by a Qualified Wood Burning Heating Professional and receive a certification prior to receiving a registration from the District. 2. Qualified Wood Burning Heater Professionals must meet the following requirements :
a. Maintain a professional certification as outlined in R ule 4901

. b. A pply to the District and be placed on a list of approved Qualified Wood Burning Heater Professionals

. 3. Qualified Wood B urning Heater Professional s are required to conduct a th o rough

a nd rigorous review and evaluation of the wood burn ing device before providing

a certific a tion to the District. 4. Once the Qualified Wood Burning Heater P rofessional completes the inspection and provides a ce rtification for the device, the r egistration is issued with a set of operating conditions for compliance with Rule 4901. This includes requirements for the wood burning device to operate in compliance with Episodic Wood Burning Curtailme nts issued by the District and prevents burn ing of any prohibited fuel types as identified in Rule 4901. 5. Registrations are valid for a period of up to three wood burning seasons from the date of registration issuance; however, certificates can be disqualified if the Distr ict finds the wood burning device is operated in violation of the requirements of Rule 4901

. 6. Upon comple tion of the three

- season period, the registration of the unit will need to be renewed and again pass an inspection by a Qualified Wood Burning Heater P rofessional

. Due to the stringent requirements for registering a wood burning device, it is expected that a limited number of residents will take advantage of registering their wood burning devices.During the r ule 4901 development process

, the Dis trict performed a worst

- case

scenario analysis of estimating the potential increase in emissions from the transition of high

- polluting uncontrolled devices to clean certified registered devices operating when pollutant concentration levels are forecast bet ween 20 μ g/m 3 and 65 μ g/m 3 (Appendix B

- Emission Reduction Analysis)

. In this analysis, the District assumed that 24% of all existing high polluting wood burning devices in the Valley would transition to clean certified units

, all 24% of devices would r egi ster these devices with the District

, and all 24% registered devices would operate on da ys when PM2.5 concentrations were projected to be between 20 and 65 μ g/m 3 . Based on this scenario, the District estimated a total increas e in emissions of only 0.22 tons per day (tpd)

.

The above mentioned scenario is based on a worst

- case and unrealistic scenario. The assumption that all wood burning devices would transition to clean certified wood burning devices was solely to calculate the absolute worst case sc enario. Through the District’s Burn Cleaner incentive program, over 8 0% of devices have been replaced with natural gas

- fired units

. This is indicative of the Valley

- wide trend of the transition of high polluting devices to clean units. Furthermore, as discussed earlier, only a minority of EPA clean certified devices are expected to register due to the stringent registration requirements under Rule 4901. A more reasonable, but still conservative, assumption would have been to assume only 20 % of the 0.22 tpd emissions would occur because of the aforementioned transitions (still assumes that all clean certified devices register with the District). Taking these more accurate factors into account and applying t hem to the previous highly conservative analysi s result s in a more representative emission increase of 0. 0 44 tpd ( 0.22 tpd x 20 % = 0.0 44 tpd ) when air quality is forecast to be between 20 and 65 μ g/m 3 . This amount is insignificant with respect to PM2.5 concentrations and does not take into account the 3.33 tpd of direct PM2.5 emissions reductions from the lowering of the curtailment threshold, and the 2.04 tpd reductions from the transition to the cleaner certified unit s

. The combination of stringent requirements that must be met to register a wood burning device, including all associated costs for receiving a registration , increased transition to natural gas

- fired units instead of wood

- fired units and the de minimis amount of emissions resulting from the fe w units tha t can be used when PM2 .5 is forecast to be between 20 and 65 μ g/m 3 will r esult in an insignificant impact during this period and Rule 4901 as a whole results in significant emission reductions

.