Explore, enjoy, and protect Philadelphia's natural environment. Air quality Resources you can use to find current air quality information for Philadelphia. Find a playground or recreation center Resources to help you find a playground, recreation center, or athletic field in Philadelphia. Events in Philadelphia parks Calendar of special events scheduled to take place in Philadelphia parks and recreation centers. Get organic materials How to get free or low-cost compost, mulch, and wood chips at the Fairmount Park Organic Recycling Center. Dispose of organic materials How to dispose of mulch, compost, or other organic materials for a cost at the Fairmount Park Organic Recycling Center. Get a trail permit Get a permit to use trails in Philadelphia. Request a dog run Learn how to get a dog run in your local park. A dog run is a fenced-in, safe area where well-behaved dogs can play off leash. Tree related services Services related to getting or taking care of street and yard trees.