When it comes to passing an emissions test it is all about how many of these particles called hydrocarbons are being sprayed out into the atmosphere. If you fail to change your oil on a regular basis, dirty oil causes a build up of these hydrocarbons inside areas of your engine’s crank case. These then get burned up, causing more of them to be released into the air through the vehicle’s exhaust. Not only will changing your oil on time help you pass this required emissions test, you will also be polluting less.