Hi Ben, I saw that there is a type of one-day tickets called "Anti-pollution Tickets" (€3.80) but they will only be sold in the event of a peak in pollution levels.
How do we know when such tickets are sold? Is there a website we can look up, or will we only know when we get to a station on a particular day? Is this type of tickets good for travelling within zone 1-3?
Thanks in advance :)
That's a great question. The anti-pollution ticket isn't sold on a predetermined schedule, but rather when vehicle traffic (and therefore air pollution) surpasses some mysterious limit.
I've just posted an article on the Paris antipollution travel pass (inspired by your question) which should hopefully answer all your questions.