The air in Ribeirão Pires today feels heavy and a bit stuffy, like the city is holding its breath. Breathing might feel just a little harder than usual, especially if you step outside midday.

It's not the best day for a long run or a vigorous bike ride, and you might want to keep the windows closed for now. If you have plans for a gentle walk, keep it short and stick to quieter streets away from traffic.

For children, older adults, and anyone with a history of breathing or heart trouble, today is a good day to take it easy indoors. Even healthy folks might notice a tickle in their throat or a little tightness in the chest if they exert themselves.

The good news is this kind of day usually passes quickly, and the air will likely freshen up by tomorrow. So take it slow, maybe enjoy a cozy indoor activity, and know that clearer air is on its way.