All of us interested in the restoration of the Chesapeake Bay — or, for that matter, any of the other nutrient over-enriched estuaries between North Carolina and Maine — need to become familiar with the current struggles going on in the Northeast over the implementation of the Clean Air Act. While the issues may seem highly technical and remote from our interests in clean water, productive grassbeds, and healthy fish populations in the Bay and other places, decisions are in fact being made now in the name of clean air that cannot help but have major effects on the costs and the long-term viability of returning our coastal ecosystems to good health.
The obvious reason for becoming engaged in these debates is that a large segment of the nitrogen excess entering these fragile coastal systems is coming from the air. The oversupply of nitrogen to the system is what causes the excess growth and blooms of algae in the Bay’s waters, ultimately starving it and the fish and shellfish living there of oxygen. In the Chesapeake, for example, we know that between a quarter and a third of the nitrogen originates from the tailpipes of motor vehicles or the stacks of fossil fuel burners such as power plants. Of this amount, about a third is deposited directly onto the waters of the Bay and its tidal tributaries; the remaining two-thirds is washed off the land by rains and snowmelt, and enters the Bay through its streams and rivers.
However, this calculation does not include any estimate for the nitrogen deposited from the air onto the nearshore coastal ocean, which serves as the single largest source of nitrogen to the Bay through currents and tidal flows. We know from our work with the Bay models that levels of nitrogen from this ocean source are elevated, not only from deposition directly on the ocean from the prevailing westerlies, but also probably from loadings of river systems to the north, which are delivering high nitrogen levels from air pollution deposited in the upper Hudson and New England, some of which originates in the Chesapeake watershed. In a way, our own air pollution is returning to haunt our Chesapeake. And not that it should be any consolation, our overloaded Bay discharges are probably contributing to the nutrient overloads of Pamlico Sound.
Of all this air deposition of nitrogen, only a small portion — that deposited to the land and washing into the Bay through its rivers and streams — was considered part of the “controllable sources of nitrogen subject to the 40 percent reduction goal agreed to by the Bay partners in 1987 and confirmed in 1992. Even that portion was little understood and has proven difficult to pin down. The rest lies formally outside the 40 percent reduction effort, and as such presents a dilemma. On the one hand, it is an area that in its complexity of players and laws and actions can overwhelm us and draw us away from those key areas where we know reductions in loadings can be achieved. On the other hand, some of the actions being contemplated to reduce loadings from the air could result in real benefits to the Bay. As we struggle to meet our 40 percent reduction goal, it is inevitable that we will turn to see what is going on with the Clean Air Act, and it is important that we stay informed and inform others of its potential impact on the Bay.
So what is the controversy all about? The Clean Air Act amendments enacted in 1990 placed a priority on dealing nationwide with toxics and sulfur oxides. Only later, and in some areas, has nitrogen control emerged as the major precursor to the formation of low-level ozone and smog. States in high-ozone areas have until Nov. 15, 1994 to come up with reduction plans, much of which will need to deal with nitrogen controls. Because of the regional nature of the the problem in the Northeast, the law provided for the formation of an Ozone Transport Commission (OTC) comprising members from 12 states from Virginia to Maine, and the District of Columbia. States failing to meet the November deadline are subject to sanctions, including the loss of federal highway funds.
A number of recent actions have been taken by OTC states to deal with the need to reduce nitrogen from both mobile and stationary sources. All jurisdictions in the Bay watershed have enacted enhanced inspection and maintenance for motor vehicles, although there are threats of backsliding in some states. Oxygenated fuels and reformulated gasoline are among other options being discussed. Part of the puzzle also involves the definition and use of RACTs, or reasonable available control technologies, for stationary sources such as power plants. The most recent action was a 9 to 4 vote of the OTC on February 1 to ask the EPA to certify the region to require the Low Emission Vehicle (LEV) or so-called California Car requirements. This would result in a 50 percent or more improvement in vehicle nitrogen emissions at a cost estimated between $130 and $700 per vehicle, depending on who is doing the estimating. Because the OTC region accounts for 40 percent of nationwide new car sales, this action could have major impact on the nationwide ozone strategy.
It would also have a significant positive impact on the Bay. There will continue to be debates over the cost-effectiveness of this and other aspects of the strategy for reducing nitrogen in the air. Some of the alternatives mandated by the Clean Air Act would affect transportation plans, commuter options, and even development patterns.
All this sounds very complicated, and it is. But one message is clear — every time a state legislature or a government air quality agency opts for lower nitrogen levels in the air, the Bay wins. And every time the decision is to back away from controls on autos or power plants or other airborne sources of nitrogen, more of the effort and more of the cost of cleaning up the Bay is placed on farmers, municipalities with sewage treatment plants, and developers to control stormwater. This is not necessarily good or bad in every case. What counts ultimately is what’s fair for everyone involved in improving our environment. And this requires the knowledge to understand true costs and benefits, the perspective to weigh the sources whatever their origins, and the courage to pursue the best mix of actions. To do this, all of us concerned about the Bay had better get smart and stay smart about the options being discussed for controlling nitrogen in our air.