ATTACHMENT B :

CLEAN AIR ACT § 110(a)(2)(D)(i) (I)

– Interstate Transport Provisions

“Each such plan shall [...] contain adequate provisions (i) Prohibiting, consistent with the provisions of this subchapter, any source or other type of emissions activity within the state from emitting any air pollutant in

amounts which will: (I) Contribute significantly to nonattainment in, or interfere with maintenance by, any other State with respe ct to any such national primary or secondary ambient air quality standard, or

The District of Columbia (District) does not contribute to nonattainment in, or interference with maintenance by, any other state with respect to the 2012 fine particulate matter (PM 2.5 ) national

ambient air quality standards (NAAQS). As explained below, pollutant levels in the ambient air

are below the standards. E missions of PM 2.5 from sources in the District are small relative to

those from other states. State Implemen tation Plan ( SIP )

- approved regulations to reduce

emissions from sources that emit PM 2.5 and its precursors are in place as appropriate

.

PM 2.5 Trends

Ambient measurements of PM 2.5 are co llected at three air monito ring sites in the District

. Results demonstrate that PM 2.5 concentrations have dropped over time. Figure 1 shows that

PM 2.5 design concentrations are well below both the 2012 annual and daily standard s

. These downward trends are likely a result of Federal control programs that limit emissions from nonroad gasoline and diesel engines, locomotives, and heavy

- duty diesel trucks.Figure 1: PM 2.5 Design Values in the District Over Time Compared to the Annual and Daily NAAQS

The trend is similar to design value trends in the Washington DC

- MD

- VA maintenance area as a whole (shown in Figure 2 , which includes 2014 preliminary values )

.

8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 Concentration (μg/m 3 )

River Terrace Hains Point McMillan 2006 Annual PM 2.5 NAAQS: 15.0 μg/m 3

2012 Annual PM 2.5 NAAQS: 12.0 μg/m 3

15 20 25 30 35 40 45 50 55
Concentration ( μg/m3 )

River Terrace Hains Point McMillan 2006 & 2012 Daily PM 2.5 NAAQS: 35 μg/m 3Figure 2: Design Values in the Washington DC

- MD

- VA Area Over Time Compared to the Annual and Daily NAAQS

Source: Kumar, Sunil for MWAQC Meeting . O zone Season Summary (September 29 , 2015),

accessed at: http://www.mwcog.org/environment/committee/committee/documents.asp?COMMITTEE_ID=14Emissions Reduction s

PM emissions are estimated as PM

- primary, which are particulates that are directly emitted by a
source; PM

- filterable, which are emissions that are collectable using a filter; and PM

condensable, which are formed after they are emitted. Filterable plus condensable emissions equate to PM

- primary emissio ns, so PM 2.5 - PRI emissions are reviewed below.

Emissions of PM 2.5 - PRI in the District primarily come from the area source sector.

Figure 3. PM 2.5 - PRI Emissions by Sector

EGUs & Non

- EGUs : In general, point sources in the District contribute a small amount of PM 2.5 compared to other sectors. There are no e lectric generating units (EGU) or other large industrial

sources of PM 2.5 emissions. The Dis trict’s last remaining EGUs were decommissioned in 2012, in part to meet permit requirements incorporated into the District’s Regional Haze SIP ( 77 Fed. Reg. 5191

, codified at 40 C.F.R. § 52.470(e ) )

.

As indicated in Figure 4, t he main source of area source PM 2.5 emissions is fuel combustion (in purple) . The largest sources of course PM (PM 10 ) emissions , which are not as relevant for the purposes of the fine PM NAAQS, are construction and road dust. ) point

2%

area

71% nonroad

13% onroad

14% 

### 2011 PM 2.5 

### - PRI Emissions

in the DistrictFigure 4. Area Source Emissions of PM in the District

Figure 5 shows that w ithin the area source fuel combustion category, the re was a large uptick in residential wood combustion (RWC) emissions in the 2008 National Emissions Inventory for the

District . This was due to changes in the calculation methodology and is not representative of

actual emissions increases

.

Figure 5. Fuel Combustion Emissions of PM 2.5 - PRI in the District

The commercial/institutional and residential sectors (not related to RWC) are the dominant area

source sectors . PM 2.5 e missions are primarily due to the use of distillate oil , which has dropped in recent years, and natural gas. The District recently proposed a regulation to reduce the sulfur content of home heating oil used in the District (62 DCR 9314; July 3, 2015) , and intends to

s ubmit a final regulation to EPA for SIP approval . S ince sulfates are a precursor to PM 2.5 , the District anticipates that distillate

- related PM 2.5 emissions will be reduced in future years.

Mobile Sources: Regional and EPA modeling indicates that o nroad emissions are expected to continue going down in future years as Tier 3 clean vehicle and fuel standards are implemented

0 100 200 300 400 500 600 700

2002 2005 2008 2011 Emissions (tons per year)

industrial comm/inst

residential/not RWC residential/RWCand vehicle turnover occurs , despite increases in population. Mobile sources, both onroad and

nonroad combined, contribute roughly on e quarter of the PM 2.5 emissions in the District

. In 2011, d iesel

- powered vehicles (which release more PM than gasoline

- powered vehicles) accounted for 54 percent of PM 2.5 emissions from the onroad sector and 88 percent of PM 2.5 emissions from the nonroad sector

.

T he District implement s an Enhanced Vehicle Inspection and Maintenance (I/M) program t o control emissions from onroad vehicles , approved by EPA at 40 C.F.R. 52.470(c))

. The District

also does extensive outreach to educate tour bus drivers and others who may be impacted by the

District’s strict engine idling time limits at 20 DCMR § 900.1. Otherwise, the District relies heavily on federal measures to reduce emissions from onroad and nonro ad engines.

Contributions from Other States

There is no EPA assessment of PM 2.5 - related transport across state boundaries

. Generally, PM .2.5 levels follow similar trends as ozone levels.

In the Cross State Air Pollution Rule (CSAPR) related to ozone transport , EPA used a contribution screening threshold of one percent of the 2008 ozone NAAQS to identify upwind states that may significantly contribut e to downwind nonattainment or maintenance problems. According to EPA’s ozone transpo rt modeling, the largest ozone contributions from the District to 2017 projected nonattainment areas in other states is 0.73 parts per billion (ppb), and to 2017 projected maintenance

- only areas in other states is 0.64 ppb. 1 Since the one percent contribution threshold for the 2008 NAAQS is equivalent to 0.76 ppb, the District’s projected contributions

are below the threshold , meaning that the District does not significantly contribute to ozone nonattainment or maintenance i ssues in any other state . Thus, it is reasonable to hypothesize that

the District does not currently contribute to any downwind PM 2.5 issues.

Conclusion

The District of Columbia is a small jurisdiction with no significant sources of PM 2.5 emissions and little opportunity to reduce emissions

. The District’s SIP contains adequate provisions , as discussed in the Infrastructure SIP submission, to prohibit sources from emitting air pollutants at levels that would significantly contribute to nonattainmen t or interfere with maintenance by other

states with the 2012 PM 2.5 NAAQS. While the District does what it can to adopt new control

measures, it historically has and will likely continue to rel y heavily on Federal measures and

measures in other states

.

1 U.S. Environmental Protection Agency [EPA

- HQ

- OAR

- 2015

- 0500; FRL

- ]. “Notice of Availability of the Environmental Protection Agency’s Updated Ozone Transport Modeling Data for the 2008 National Ambient Air Quality Standard (NAAQS).” Found at: http://www3.epa.gov/airtransport/pdfs/FR_Version_Transport_NODA.pdf (signed by Stephen D. Page, July 23, 2015).