The air in Araruama today feels a bit heavy, like the kind of afternoon when the breeze doesn't quite stir. Breathing is fine for most, but there's a slight thickness that you might notice if you step outside after being indoors for a while. It's not unpleasant, just a little less crisp than a perfect spring morning.
You can certainly go about your day outside, but it might be wise to take it easy if you plan on a long run or a heavy bike ride. The air is okay for a stroll or sitting on the porch, but opening windows wide all day could let in that stagnant feel. If you have young children or older relatives who are sensitive to stuffiness, maybe keep the windows cracked rather than fully open.
For anyone with asthma or a heart condition, it's smart to avoid prolonged exertion today. The air isn't bad enough to cause alarm, but it's not the best day for pushing your limits. A gentle walk is fine, but skip the intense workout until tomorrow when the air might freshen up.
The good news is that this is just a mild, hazy day, not something to worry about. Leave the windows ajar, take your time, and it'll pass without much fuss. By evening, things often settle down, so you can look forward to a more comfortable night.