If you thought that NOx, and PM 10 and 2.5 were the only serious air pollutants to worry about, think again. The latest toxic (carcinogenic) vehicle exhaust pollutant to occur at levels that can be considered potentially damaging to health is the gas, 1,3-Butadiene.
This substance may well join the pollutants already added to a list which are currently regulated in France. If the French government forwards this proposal to the European Commission, by the end of 2019 it could be included in the ongoing revision of the 2008 directive on monitoring air quality. Read more on this here