Indirect grenehouse gases
Carbon monoxide (CO), nitrogen oxides (NOx) and other non-methane volatile organic compounds (NMVOC) have an indirect impact on the greenhouse effect through e.g. ozone (O3) formation. Emissions of these gases are limited under other international agreements and the obligations of the Kyoto Protocol on the limitation and reduction of emissions do not concern them. Nevertheless, their emissions must be reported to the Convention in national greenhouse gas inventory reports.
Validity of the definition