NOx (and PM) is a local, temporary consequence. Catalysts exist to remove NOx out of exhaust gasses. They are perfectly serviceable.
Carbon dioxide is a permanent, global issue, where no (large-scale) capturing/cleaning methods exist.
NOx removes itself out of the atmosphere through natural means, CO2 does not.
You can close the cycle, hence 'ignore' CO2 emissions since they cancel out, and deal with NOx using today's existing technology. Same thing for PM and sulfur.
Re:How green is blue hydrogen?
by the_third_wave on Saturday August 14, 2021 @11:54AM
(#28181629)
Tell that to the Dutch authorities who are using NOx emissions to restrict industry and agriculture...
> NOx removes itself out of the atmosphere through natural means
...because of this [1], among others.
[1] https://en.wikipedia.org/wiki/Human_impact_on_the_nitrogen_c...
...if and when you burn them with pure oxygen like done in rockets. Mostly they're burnt using using atmospheric oxygen though, leading to the production of nitrogen oxides (NOx) which come with their own problems [1]. It is possible to reduce the emission of these gases [2] at the cost of increased complexity and cost.
[1] https://en.wikipedia.org/wiki/NOx#Health_and_environment_eff...
[2] https://en.wikipedia.org/wiki/NOx#Regulation_and_emission_co...