JUDY WOODRUFF: But, first, hundreds of thousands of Volkswagen and Audi owners have been left in the dark about what to do after learning their diesel-fueled cars are emitting up to 40 times the amount of nitrogen oxide allowed by the federal government.

Special correspondent Cat Wise takes a look at the reaction in Portland, Oregon. It is taking a lead role in a multistate investigation of Volkswagen, and has the most affected vehicles, per capita, of any state in the country.

CAT WISE: Gourmet meats are sizzling, and business is brisk at the Lardo sandwich shop in one of Portland's hip new neighborhoods. Owner Rick Gencarelli is a true Portlander, carefully sourcing the food in his restaurant and driving an ecologically friendly car.

At least, he thought he was driving an ecologically friendly car until last month. That's when he and 500,000 other U.S. owners of Volkswagen and Audi's so-called clean diesel cars learned they had been duped.

RICK GENCARELLI, Volkswagen Owner: You're trying to make the right decision for the environment, and then it turns out that it's 30 or 40 times the allowed amount of emissions, which is — that's just completely heartbreaking.

CAT WISE: Gencarelli says he was already starting to feel guilty driving his 2011 Jetta TDI after the news broke. Then he discovered a note left by an anonymous person on the windshield that read in part: “Your car is currently polluting at rates higher than nearly any modern gasoline car today, two to four times more than a Chevy Suburban, not to mention that V.W. lied to you and the public.

RICK GENCARELLI: I feel horrible. Like, I want to just wear a mask because I feel like I'm being judged so harshly. The note kindly says that I should consider a new car, but then what do I do with this one? It's still going to be on the road.

CAT WISE: In fact, many V.W. owners in Portland and around the country are wondering what to do. Volkswagen has yet to reveal plans for fixing the emissions problems, and vehicle values are dropping amid the uncertainty. Nationally, more than 250 lawsuits have been filed against Volkswagen and more are likely as states, car dealers, and consumers grapple with the long-term implications of the company's fraud.

One of those filing suit is Jamie Saul, a Portland environmental law professor and a dad in a busy household. Saul and his wife, Alex, have been big fans of the newer Volkswagen diesel vehicles. They have owned two and convinced several family members to buy them as well. But now Jamie is part of a class-action lawsuit against the company filed in a California federal court.

We caught up with Jamie as he was heading out for his morning commute in his family's Jetta TDI SportWagen.

So, tell me about that day that you heard the news. What was your reaction?

JAMIE SAUL, Volkswagen Owner: I was shocked. I was shocked and disappointed at Volkswagen. It's one of the few major corporations that I thought was really trying to do the right thing. There are a lot of late-model TDIs in our neighborhood and in Portland generally, because I think consumers in Portland like the idea of having a fuel-efficient, clean car that's fun to drive and practical for their family needs.

CAT WISE: Saul and his wife are now trying to drive less, and ride their bikes to work more often, but that's a big hassle when they have to get the kids around town. They'd like to sell the car, but who would buy it and at what price?

JAMIE SAUL: I think the people who own these cars need to be compensated for the lost value in the cars on the secondary market. And they need a real-world fix that solves the problem, while not undermining the fuel economy and the performance of these cars.

CAT WISE: While owners have been struggling, Volkswagen dealerships are also feeling the pain. The company has told dealers to stop selling their inventory of diesel vehicles, which typically account for about 20 percent of sales.

But Volkswagen is reportedly reimbursing U.S. dealers for expenses they incur during the scandal. We reached out to Portland area Volkswagen dealerships, but none would agree to speak with us on camera. Nationwide, sales of V.W.s are expected to take a significant hit. But the emissions scandal isn't just impacting new car dealers. It's also having a big impact in the used car market.

MONTY KING, Oregon Vehicle Dealers Association: The values are just dropping like a rock.

CAT WISE: Monty King is president of the Oregon Vehicle Dealers Association and represents used car and truck dealerships.

MONTY KING: The dealers are very concerned, because they're small business people. And if they had bought one of these V.W.s at the auction or even taken it as a trade-in, and now because of this, the value drops, say, $500 or 1,000, they're going to take the loss. I think V.W. is responsible for that.

CAT WISE: King says independent used car dealers aren't expecting the same level of support as V.W. dealerships.

MONTY KING: There's 120,000 used car dealers in the United States. And if every one of them has one of these, what do you think the chances are of V.W. helping? I'm not real excited about that possibility.

CAT WISE: One of the big questions on many V.W. owners' minds here in Portland is, can they still legally drive their car?

Oregon, like 29 other states, has a vehicle emissions testing program in several cities. The goal is to improve air quality by making sure vehicles are properly maintained and not emitting pollutants that exhaust systems are designed to catch.

GERRY PRESTON, Oregon Dept. of Environmental Quality: I know it seems to be out there that vehicles, if you own these, you're going to fail. And that's just not the case.

CAT WISE: Gerry Preston is in charge of the vehicle inspection program for Oregon's Department of Environmental Quality. He says that impacted V.W. diesel cars won't automatically fail the required biannual test. The state is waiting for a recall to happen, and then owners will be expected to get those repairs made.

GERRY PRESTON: We certainly care about the issue, and we know that nitrogen oxide, the component that we're talking about, can cause problems with asthma, emphysema, and bronchitis, and things like that, so we're very concerned about that. However, we're letting EPA take the role, as are most states, to let the recall process take its form, and then after that, when they come back in, if they haven't gotten the recall done, then we will be looking at that.

CAT WISE: For now, Jamie Saul and many others are waiting for news about that recall expected in the next few months.

For the PBS NewsHour, I'm Cat Wise in Portland, Oregon.