You should avoid or limit outdoor time if you can. The particulate matter is extremely dangerous because if you breathe it deeply into your respiratory system, it can enter the bloodstream and cause a variety of health problems, said Richardson.
Poor air quality, much like smoking cigarettes, is something that's likely to present long term health problems, even if short term issues are tolerable. So yeah exposure to second hand smoke once in a while is no big deal. The BAAQMD is is tasked with monitoring and controlling air quality, so it may not have been appropriate for Richardson to opine on health issues - but there are plenty of scientific studies that have reported on the long term risk.
Air Pollution and Public Health
Each year in the UK, around 40,000 deaths are attributable to exposure to outdoor air pollution which plays a role in many of the major health challenges of our day. It has been linked to cancer, asthma, stroke and heart disease, diabetes, obesity, and changes linked to dementia.