Which emission factor is associated with poor engine performance?

The emission factor associated with poor engine performance is the efficiency of aged spark plugs. Spark plugs play a critical role in the combustion process within an engine. When spark plugs age, they can become fouled or worn, which leads to incomplete combustion of the fuel-air mixture. This inefficiency can result in higher emissions of unburned hydrocarbons and greater levels of other pollutants. Additionally, aged spark plugs can cause misfires, leading to a rough engine performance and decreased fuel efficiency, which ultimately contributes to more emissions.

In contrast, excessive engine cooling and high fuel pressures may not directly indicate poor engine performance. Excessive cooling can actually be a protective measure, while high fuel pressures typically indicate a properly functioning fuel system, at least in some contexts. Carbon dioxide reduction refers to techniques aimed at reducing greenhouse gas emissions, which, while important, does not pertain directly to the performance issues caused by engine component efficiency.