What is this, an article for ants?
I wonder if the best approach to regulating pollution is go from regulation and policy change or try to come up with solutions (startups) that tackle the problem directly...
Product focused on indoor pollution - doesn't help that much as people still spend some time outside.
Product that "cleans" outdoor pollution - the only way to get money from that is to sell it directly to government (maybe local). Unless you develop something really groundbreaking it's cheaper to do regulation and policy changes.