What are the vehicle inspection exhaust emission standards?

[McAdriana]

Vehicle inspection exhaust emission standards: Carbon monoxide: A (700mg/km); B (500mg/km); Non-methane hydrocarbons: A (68mg/km); B (35mg/km); Nitrogen oxides: A (60mg/km); B (35mg/km); PM particulate matter: A (4.5mg/km); B (3mg/km). The general process for vehicle exhaust emission testing: 1. Information entry: The computer enters information, registers vehicle details, and assigns an inspection line based on vehicle characteristics. This process is automatically completed by the computer. 2. Designated inspection line: The dispatcher directs staff to drive the vehicle to the designated inspection line. Supervisors do not have the authority to change the inspection line. 3. Confirmation of inspection line: The control room verifies whether the vehicle has entered the correct inspection line. Without confirmation, the next step cannot proceed. 4. Exhaust emission testing: The inspector follows the prompts on the computer screen to perform the test. Correct operation is required for a successful test. The test results are compared with standard values and then uploaded to the server by the system. 5. Payment: Finally, payment is made at the environmental inspection fee counter. If the vehicle fails the test, it must be rectified and retested. Vehicles that pass the test are issued an environmental label.

[VonSpencer]

Last time I went to the vehicle inspection station, the staff mainly checked the exhaust emissions. Currently, China mainly follows the National V and National VI standards. For gasoline vehicles, they test values like carbon monoxide, hydrocarbons, and nitrogen oxides. My old car barely passed the inspection last year, and the inspector said older cars are most likely to exceed the limits during cold starts. It's important to regularly maintain the catalytic converter and avoid using low-quality gasoline, as excessive carbon buildup can easily lead to exceeding the standards. Before the annual inspection, it's best to drive on the highway for half an hour to clean out carbon deposits. If the emissions fail, you'll have to go through repairs and re-inspection, which is quite troublesome. Standards vary slightly by region, with stricter enforcement in big cities. Some older cars that don't meet the standards even face driving restrictions.

[LeOwen]

I've studied the exhaust emission standards, and the government has been tightening regulations in recent years. The China VI standards are particularly stringent, with nitrogen oxide limits reduced by over 40% compared to China V. During testing, vehicles must be placed on a chassis dynamometer to simulate real driving conditions. The most concerning issue is electronic control system failures, such as a faulty oxygen sensor causing incorrect air-fuel mixture ratios that directly lead to excessive emissions. Surprisingly, small-displacement turbocharged engines tend to meet standards more easily than large-displacement naturally aspirated ones due to more precise combustion control. I recommend regular replacement of air filters and spark plugs, and never use high-pressure water jets to clean the catalytic converter. I recently added a bottle of fuel additive, and the emission readings during inspection showed significant improvement.

[SanEleanor]

A friend recently asked me about failing the emission test due to excessive exhaust levels. There are mainly three key indicators to check: carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) concentrations. The emission limits vary for vehicles with different engine displacements. For my 1.5L car meeting China's National V standard, the CO limit is no more than 1 gram per kilometer. Cold starts are the most disadvantageous—testing stations usually measure emissions after warming up the vehicle. Older cars often fail due to faulty oxygen sensors, which tend to become sluggish after 7-8 years of use, leading to inaccurate air-fuel ratios and directly causing excessive emissions. Before the annual inspection, remember to check if the catalytic converter is clogged, replace the spark plugs, and use higher-purity 95-octane gasoline for cleaner combustion.