What should I do if the automobile exhaust exceeds the standard throughout the year?

Cleaning the three-way catalytic converter with oxalic acid has a miraculous effect. Just go to the roadside garage. It won't cost much.

Oxalic acid crystals are generally available in local chemical stores. You can find a garage to dismantle the three-way catalytic converter and mix oxalic acid crystals with water to make oxalic acid solution. Plug one end of the three-way catalytic converter and pour oxalic acid solution into the other end. Soak for one hour to make oxalic acid solution and ternary solution fully react; Easily soak the removed oxygen sensor. After one hour, pour out the oxalic acid solution in the three-way catalytic converter, blow the three-way catalytic converter clean with an air gun, load it on the car, and you can go to the annual review.