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VADEQ Comments on Combining the Baltimore and Washington 

Ozone Nonattainment Areas

As stated during the previous call on this issue, the VADEQ is strongly opposed to the recommendation from the 

District of Columbia and the State of Maryland, to reverse past precedent and combine the historically separate 

nonattainment areas of Baltimore and Washington, DC under the 2008 ozone standard. Furthermore, we believe 

that there are serious flaws in the arguments presented to support such an action:

• We believe that the Baltimore area is unduly influenced by the outlying and flawed Edgewood monitor. 

This monitor is not representative of air quality in the Washington area, and may not be representative of

most of Baltimore as well.

• We believe that combining these two nonattainment areas would do little or nothing to produce 

additional meaningful emission reductions to improve ozone air quality in either area, and certainly would 

have no impact on the worst case monitor identified above.

• We believe that substantial emissions reductions have and will continue to occur regardless of the 

nonattainment designation process that will result in improved ozone air quality in Virginia and downwind 

areas.

• We believe that combining these areas would create a serious new burden on both the air quality and 

transportation planning processes for both areas. 

Air Quality Data

Air quality in general for both the Baltimore and Washington areas is consistent with a marginal level of 

nonattainment. In addition, there is no noticeable gradient of increase between the areas that would indicate 

substantial influence or contribution. The sole exception to regional ozone levels is the Edgewood, MD monitor 

which has 2011 design value that is a full 10 parts per billion higher than any other monitor in these areas. We 

believe that the reason for this wide discrepancy in air quality is due to a unique combination of local influences 

such as meteorology, pollution recirculation, and others at this monitor. Because of this, we do not believe that

this monitor is representative of the area(s) as a whole, or of the DC area contribution to Baltimore. As such this 

monitor should not be used to drive the air quality planning and control requirements for the Washington area.

We also understand that this monitor is located the property of the Army’s Aberdeen Proving Ground which has 

experienced significant recent growth as a result of the last Defense BRAC realignment which may also play a part 

in the elevated ozone levels at this monitor. We would insist before any combination action, that this monitor 

undergo a detailed regional evaluation to better understand the ozone formation factors in play, including 

Chesapeake Bay breeze and pollution stagnation and recirculation. We would also suggest that this monitor be reevaluated for site suitability due to the recent growth in the area.
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Contribution Modeling

DEQ has performed a brief review of the MDE modeling provided to EPA Region III to support their position. We 

find the summary presentation to be substantially lacking in terms of modeling and methodology. The immediate 

point is that all the results presented are for a limited number of days and are of 2002 and 2007 vintage. Much has 

changed since these base case years in terms of control programs and emissions reductions. Regarding the very 

selective episode that was chosen, we can only assume that it was the one that best supports their position. As 

you know, current SIP quality modeling normally requires multiple episodes with different characteristics or even 

an entire ozone season. There are also significant limitations to the screening inventories used in this analysis and 

no information is provided on model performance.

The part of this analysis that we take the most issue with is the way in which the impact analysis of the DC area on 

Baltimore was performed. Standard regional modeling practice is for this type of analysis is to zero out the 

emissions of an area and subtracting it from the base case to determine its contribution to other areas. This is 

what was done for the contribution modeling for Maryland and Baltimore in Slides 1 and 2. However, the DC 

contribution analysis presented in Slide 5 is performed in reverse by zeroing out all other domain emissions. This 

analysis is not meaningful and is done incorrectly. Conducting a brute force zero out run that includes just the DC 

emissions completely changes the chemistry in the model and the results cannot be reasonably relied upon. We 

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believe that the more appropriate way to determine contribution is to use the much more comprehensive and 

rigorous regulatory modeling used to support the CSAPR rule which determined that all of Virginia contributes 

about 8 parts per billion (9%) of the 2012 ozone levels at the Edgewood monitor.

Finally, performing this type of analysis on just one area is no more compelling than what similar analyses for any 

number of other “nearby” areas would produce. All the MDE analysis attempts to do is to incorrectly single out 

and imply that the Washington, DC area as the main contributor to most of Baltimore’s ozone problem.

Emission Reduction Data

Significant emissions reductions have occurred in the Washington area and in all of Virginia during the past ten 

years in the two major NOx precursor sectors, electric utilities and motor vehicles. We also predict that these 

reductions will continue into the future.

In the Washington, DC area alone, it is estimated overall NOX emissions will be reduced from all sources by over 

90,000 tons per year between 2007 and 2025. Again much of this reduction comes from the power and mobile 

sectors.

In the case of motor vehicle emissions that are the main source of NOx emissions in the area and the sector 

specifically named as the main contributor to the Baltimore area, the news is even better. Emissions from this 

sector are expected to be reduced by 80% or about 65,000 ton per year between 2007 and 2040. A similar percent 

reduction can also be expected in Virginia’s overall motor vehicle emissions during the same period. Any further 

significant motor vehicle control programs such as Tier 3 and low sulfur fuels will add more to these reductions.
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DC Motor Vehicle Emissions Trend

 

With regard to total Virginia NOx emissions from the power sector, we have seen a steady and significant 

reduction in emissions since 2002 of about 46,000 tons per year. Again, we expect these emissions to continue to 

decrease out to 2016, even with the addition of 3,100 megawatts of new coal and natural gas capacity at a 

hypothetical 100% capacity.
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However, all this current and future success comes with a price; we have now reached a point of diminishing 

opportunities for and return from future controls. The power sector transition that is underway is going to take its 

course, helped along with by additional technology and/or transport based control programs. The same can be 

said for the non-utility stationary combustion sector that is going through a similar transition. Mobile emissions 

are mainly driven by federal engine and fuel standards. What is left for us to do at a local level amounts to nibbling 

around the edges at great cost and little benefit. The example already identified is the recent analysis by the 

transportation planning group in DC where the next most “feasible” transportation control measures would 

produce only 220 tons of NOx reductions at a cost of $85 million per year.

Commuting Patterns

To further define the influence of Washington based traffic on the Baltimore area, the following data was obtained 

from the latest National Capital Region transportation modeling exercise. These data show that during a typical 

morning commute in 2007, only 1.4% of the total trips in the Washington area had a destination in the Baltimore 

area. Likewise during the afternoon commute, 1.5% of total trips are to the Baltimore area. Furthermore, it is 

estimated that there will be no meaningful increase in these inter-MSA trips out to 2030 as shown below.

Vehicle Trips Originating in the Washington DC Area

Planning Implications

We continue to believe that the combination of these two well established areas and associated organizations 

would seriously disrupt, complicate, and slow the ability of both areas to perform air quality and transportation 

planning in the future. The increasing political and agenda driven goals of some of our partners in the DC planning 

process is already causing us to explore other possible arrangements for performing air quality and especially 

transportation planning in the future.