What is the acceptable limit for CO (Carbon Monoxide) emissions in an exhaust system?

The acceptable limit for carbon monoxide (CO) emissions in an exhaust system is typically established to ensure that vehicles operate within a range that minimizes harm to the environment and public health. The range of 0.01 to 0.5% volume aligns with governmental standards and regulations aimed at controlling air pollution.

This limit reflects the recognition that while CO is a natural byproduct of combustion, excessive levels can be harmful, leading to serious health issues and contributing to smog formation. The specified range allows for sufficient margin to maintain vehicle performance while also ensuring that emissions contribute minimally to overall air quality degradation.

Although other values may be proposed, they often exceed levels deemed acceptable based on emissions testing protocols and environmental protection guidelines. By adhering to the specified range, inspectors can effectively monitor and enforce compliance with emissions standards, thereby enhancing efforts to reduce pollution from motor vehicles.