Here’s some more info:
“ Adams said even at lower levels of PM 2.5 concentration, the particles had a tendency to hook into the lungs easier than most air particles, meaning even short-term levels of pollution can increase risk of cancer, heart attacks and strokes. ”
“This is the highest level of alert and everyone — from the most vulnerable to the physically fit — may need to take precautions to protect themselves from the filthy air,” he said.
“Nitrogen dioxide is a toxic gas produced by diesel vehicles that is linked to respiratory problems. Its levels are increasingly in focus after Volkswagen was found by US authorities to have cheated emissions lab tests.”
Seeing as you have children, I highly advise you to do some research on this topic.