the limits on the harmful emissions are the same as the wltp, multiplied by a conformity factor. the conformity factors consider the error of the instrumentation, that can not guarantee the same level of accuracy and repeatability of the laboratory test, as well as the influence of the pems itself on the vehicle that is being tested. for example, during the validation of the nox emissions, a conformity factor of 2.1 (110% tolerance) is used.