Outdoor pools are safer in that they are ventilated, but you are still dealing with harsh chemicals and the potential for other nasty things (I am sure so many kids pee in the water, which isn't caught. Only when actual waste is seen can the guard know to close the pool.)
There is some research out of England- you could google "pool safety" + asthma + England for the article, that strongly urges against indoor pool use for babies and toddlers, due to respiratory concerns.
I brought my kids into our own pool at 6 months and the community pool and beach around 8 months. Use a water diaper and plastic pants, covered in a suit. I strongly urge against using any floaties or devices with babies in the water. You should be one-on-one in physical contact with them at all times. I know some parents use floaties after 2, so kids can feel more independent, and I don't fault them. I just taught mine to swim gradually, letting them go a little further each time but still 100% there for them, until they learned.
GOOD Luck and enjoy this nice, hot weather!