California's Central Valley has struggled with some of the worst air quality in the United States for years, and yet the regulatory agency charged with monitoring and improving that air quality, the San Joaquin Valley Air Pollution Control District, is on the verge of giving an OK that would make the air we breathe substantially dirtier.

District regulators have tentatively signed off on the proposed Hydrogen Energy California power and chemical plant near Tupman in western Kern County. The air district has given its preliminary approval on the plant, which will run on coal and petroleum coke, despite having determined that the project would exceed emissions standards in five categories, including a mind-boggling 1,587 percent of the government's threshold for nitrogen oxide, a primary contributor to air pollution.

Particularly bothersome is the air district's arrangement with SCS Energy LLC, the Massachusetts-based company hoping to build the Tupman plant, to "mitigate" the effects of the excessive pollutant levels by paying "fees" that the air district can use to reduce emissions elsewhere in the Central Valley. That has a rotten-egg smell to it, sort of like the odor emitted by sulfur oxides, the limits of which, incidentally, the plant will be allowed to exceed by 9 percent. That arrangement -- not uncommon -- can be characterized like this: Give us our permit to operate here, and we'll give you some money to take your air pollution fight somewhere else.

This deal still must be approved by the California Energy Commission, and a public hearing on the district's preliminary determination is scheduled for April 2. The air district should be prepared to provide details about the so-called "mitigation fee." How, exactly, will that money be used to combat air pollution, and by what measurement can we be assured that the trade-off is a net gain for our lungs? Would other companies, especially those capable of operating within the established emissions limits, be able to conduct business without further restriction, or would special allowances for HECA change the equation?

Air quality regulations can be a confounding and occasionally contradictory stew, and, justified or not, ordinary residents often feel they bear the brunt of enforcement action -- be it that $29 million fine for failing to hit regional air quality targets or "no burn" restrictions. Can we regular folk "mitigate" our fireplace use by trading clean-air credits with our neighbors? Didn't think so.

Without question, HECA has its positives -- for starters, 200 permanent jobs. The plant's primary product, other than energy, is fertilizer, for which demand is strong. (Much of what is used in the Central Valley today is imported from China.) Also, federal energy officials believe HECA is a project that's worth the investment in part because it utilizes carbon capture and sequestration technology, which collects waste carbon dioxide and deposits it in an underground formation. That captured CO2 would also benefit Occidental Petroleum by aiding in its extraction of crude oil.

And, after all, Kern County is California's alternative energy capital. This is the sort of project, one could argue, that belongs here.

We would argue that HECA must prove that it's environmentally appropriate, given the fact that Kern County is not just an empty medium for energy development -- it's a fast-growing place where people breathe.