Sure, we already have a load of regulations to make cars less pollutive. Would this be unreasonable? People are already putting this in their car, just not on t

Sure, we already have a load of regulations to make cars less pollutive. Would this be unreasonable? People are already putting this in their car, just not on the business end. It's also not just other drivers or the poor environment: a huge number of people (I'd speculate that it's the majority) live near busy roads. Adverse health effects from breathing near a busy road are common knowledge.