Air quality in the SF Bay area is a very localized condition. The South bay, where Silicon Valley is located, has "spare the air days" when the North Bay has good air quality (due to Ocean air inflows). Also any number of startups are jumping on IoT (Internet of Things) applications by creating a mesh of sensors to measure air quality, water quality, tailpipe emissions, etc. A solution in search of a market...
PG&E last year sent a survey out to its electricity customers to find out how many households have in room air cleaners and how long they are used each day, as PG& E's IoT smartmeters showed higher electricity usage during air quality events..