By Kevin R. Johnson

President Obama has less than 18 months left in a presidency of which he can be proud. Let us not forget that the president took office as the economy was in a tailspin and hemorrhaging jobs at a rate not seen since the early 1930s.

He can now boast a net gain of seven million jobs, a manufacturing renaissance, and a recovery that appears to have real momentum at last. And thanks in large measure to the Affordable Care Act, some 17 million additional Americans now have health insurance.

The president has also forced the issue of wealth disparity into the national debate, pressed Americans to confront the damaging legacy of racial segregation, and spoken out against unfair treatment of African Americans by the police and other forms of injustice.

Of course, Obama would be first to acknowledge that there is more to do. Recently, he addressed the NAACP's annual meeting in Philadelphia as part of a bold push to reduce mandatory minimum jail sentences for nonviolent drug offenders, a disproportionate number of whom are black and Hispanic men.

But one of the areas where much work remains is providing an economic lifeline to urban areas that have yet to fully benefit from the economic growth in recent years.

Many communities that enthusiastically fueled the president's astonishing rise to the apex of American politics continue to struggle. Unemployment among African Americans is at 9.5 percent. While this is the lowest it has been since before the Great Recession, it is much higher than the overall national rate of 5.3 percent. As important, wages have barely budged over the last year, and stagnant wages are a particular problem for people on the lower rungs of the socioeconomic ladder.

The challenges in finding good jobs at decent wages are especially acute in Philadelphia. This spring, a study by Drexel University's Center for Labor Markets and Policy showed that only one in 10 young African American males in Philadelphia was employed in 2012-13. This was among the lowest rates among big cities. And if these numbers have improved a little in the last few years, it remains true that urban teens are doing much worse than kids in the suburbs.

Of course, creating new jobs will be easier said than done in what is left in his historic tenure. The president asserts that expanded trade will create new jobs, and he pushed hard for approval to complete new trade agreements. At the same time, Congress will likely reject a massive infrastructure repair and rehabilitation plan. And even policies many Republicans favor, such as corporate tax reform, will have to wait until after the election. It may be that the best option the president has right now rests on the ancient oath doctors take: First, do no harm.

To that end, the president can remain steady at the helm, finding common ground with business and labor groups on whatever can be done to promote and not hinder job creation. For example, on Oct. 1, the administration is set to lower the allowable ground-level ozone pollution from the current 75 parts per billion to a range of 65 to 70 parts per billion. That seems like a good idea, especially in metropolitan areas like ours that are accustomed to ozone alerts in the hot and humid days of summer.

But we know this has an economic cost. The Environmental Protection Agency acknowledges that this could cost up to $15 billion, and groups representing home builders, farmers, contractors, and others figure it will cost a lot more. The National Association of Manufacturers points to a study that estimates that the cost would be 1.4 million fewer jobs and a $140 billion loss in economic growth for each of the next ten years.

The president himself knows the cost could be steep. That was one of the reasons he procrastinated on pushing for the new standards three years ago.

With Obama's leadership, environmental stewardship has become a higher national priority, and we have made strides in improving air quality. However, the current ozone standard was approved only in 2008, and it took until this year, in some cases, for plans to reach that standard to be finalized and implemented.

Philadelphia, which is in the middle of the bustling and densely populated Eastern Seaboard, has to grapple with ozone sources outside the region. The only way it could comply with the new limits would be to curtail economic activity and growth locally, and the people who would be adversely affected would be those already struggling to make it.

The president certainly understands that a triumphant exit in 2017 is by no means assured. Economic uncertainty in Europe and China and instability in the Middle East could erode economic gains just as people are getting back on their feet. While he cannot fully control these forces, he can avoid doing anything that would put the brakes on the economic recovery and undermine job creation in the very communities that have supported him most.