The lazy hazy days of summer — San Joaquin Valley style — are upon us.

We are in a signature Central Valley heat wave.

That means the Delta breezes, for all practical purposes, have gone AWOL.

Temperatures are now coming up a few degrees shy of 110 degrees.

The incessant humming of valley air conditioners is to the ears of PG&E hedge fund investors.

 The accompanying low humidity has firefighters on edge as illegal fireworks burst in air.

Speaking of air, the skies have abandoned the natural array of blue in exchange for the gray scale.

The gray skies you see now has air pollution slowly shrinking visibility with every passing day until the breezes kick back up.

Go back 25 years or so, and this is what summer skies in the Northern San Joaquín Valley looked like day in and day out.

Besides getting worse during heat waves such as the one we are now enjoying, it got darker and visibility shorter the farther south you went toward Bakersfield.

It has nothing to do with climate change.

It is geology.

The Great Central Valley is essentially an oblong, deep bowl.

Scientists reference it as “one of the more notable structural depressions in the world.”

It covers roughly 20,000 square miles stretching 450 miles from Redding to south of Bakersfield.

The valley ranges from 30 to  60 miles in width.

It is created by four mountain ranges that surround it — the Coastals, the Cascades, the Tehachapi and the Sierra — the last tops 14,000 feet in spots.

What we see today will start clearing up by Wednesday when the winds return.

It is far better than in the early 1990s.

That’s when the San Joaquin Valley had half the population and roughly 50 percent more air pollution particles.

It is not magic — or natural evolution — why we have basically 50 percent more people and half the pollution.

Reformulated gas — the summer blend that we all curse when it adds to the cost at the pump — is one big reason.

So are catalytic convertors and a repertoire of other measures from banning of most open burning to tweaks on non-transportation pollution sources.

It is clear we’d have air pollution issues in the valley even without climate change.

It is also why water — or the periodic lack thereof — isn’t the only major threat to the San Joaquin Valley’s economic vitality and livability.

The Environmental Protection Agency eight years ago tightened the ground ozone standard to a limit of 70 parts per billion, down from 75 parts per billion.

The EPA might as well as have handed down an edict that the San Joaquin Valley had to find a way to turn decomposed granite into gold.

The San Joaquin Valley Air Pollution Control District over the years has pointed out you could remove every one of the valley’s 2 million vehicles as well as ban thru traffic on Highway 99 and Interstate 5 plus stop all train traffic and still not meet the previous standard let alone the new one.

The EPA essentially conceded the point in 2015 when they noted most of California — specifically the San Joaquin Valley, Los Angeles Basin, Inland Empire and the Sacramento Valley — won’t be able to meet that standard by 2025.

 But when it comes to the San Joaquin Valley, the federal EPA is downright pragmatic compared to Sacramento.

Under the previous federal standards ground ozone pollutants from vehicles, manufacturing plants, farming, utilities, and refineries exceeded the target level 35 to 40 day a year. The tougher state level was unattainable roughly more than 100 times a year.

While there have been  strides in San Joaquin Valley in terms of airborne particles, there has not been a single year since 2000 when there has been not been excessive high ozone days as well as an excessive number of 24-hour periods of high particle levels that exceeded the acceptable levels of three days.

 Still, steady improvement has come to the valley’s air quality since the 1990s despite a significant gain in residents that has kicked the region’s population up to 3 million.

Lurking out there are a lot of severe financial penalties ranging from fines to loss of federal highway tax dollars that are in jeopardy if standards aren’t attained. So far, the state and federal governments have been reasonable especially given the struggles the valley has made.

It also may have something to do with close to 60 percent of the country’s fruits, vegetables, and nuts are grown in the San Joaquin Valley. And while farming has made great strides it still has a major impact on air quality.

Much of the air quality problem is indeed rooted in geography.

Unlike Omaha in Nebraska or Sioux Falls in South Dakota, everything is not flat for hundreds upon hundreds of miles allowing the wind to blow away and dissipate pollutants. Nor is it San Francisco or the Bay Area where almost constant prevailing winds carry smog away almost daily.

The San Joaquin Valley portion of the Central Valley stretches 250 miles from the Delta to the Tehachapi Mountains flanked by the Sierra to the east and Coastal Ranges to the west.

It creates a catch basin that holds the smog to such a degree that not too long ago during hot, stagnant summer days the area around Bakersfield looked like it was covered in fog making it impossible to see the foothills less than 10 miles away.

Part of the problem, but not all of it, is air pollution blown into the valley from the Bay Area an even Sacramento.

Studies a few years back showed that 27 percent of the air quality issues in the Northern San Joaquin Valley — San Joaquin, Stanislaus and Merced counties — came from those two outside areas. By the time you got down to the mid-valley around Fresno outside emission culprits dropped to 11 percent. That number dropped to 7 percent in the southern valley.

None of this may pique your interest until you understand future steps to further improve air quality will cost you and cost jobs. It’s because to further reduce emissions they have to be reduced at the source.

That puts an extreme non-attainment burden for air quality on the San Joaquin Valley that the Congressional Budget Office once succinctly referred to as the nation’s new Appalachia. It’s because the valley’s economic and social issues put it at a distinct disadvantage in attracting jobs compared to much of the rest of the nation.

The challenge now is to keep improving air without hurting some of the nation’s most economically vulnerable families in the country.

Yes, we want cleaner air but we also need to be able to survive.

It’s a tough balancing act.

It is made worse by the fact even if it is substantially healthier today to breathe in the valley than it was 20 years ago bureaucrats pulling down healthy six-figure checks in Sacramento and in Washington, D.C., and savoring the bounty of the San Joaquin Valley at meals could mandate compliance to standards that could make it difficult for those working to provide their food to house, clothe and feed their own families.

This column is the opinion of editor, Dennis Wyatt, and does not necessarily represent the opinions of The Bulletin or 209 Multimedia. He can be reached at dwyatt@mantecabulletin.com