Use of nitrous oxide (N20) doesn’t necessarily increase the oxides of nitrogen (NOX) that pollute the air, Of course, NOS makes “race only” systems that are not legal for use on pollution controlled engines. However, many NOS systems have received certification for 50-state emissions legal use in the United States. The approvals for use on emissions controlled vehicles were obtained by independent laboratory testing which proved that these NOS systems do not increase tailpipe emissions in normal driving conditions.
