A large study of 50 urban parks in Southern California measures park use by nearby residents and other users across high-, medium-, and low-poverty areas, finding that parks are used less in high-poverty areas. Those who do use parks in high-poverty areas, however, on average use the parks more per week, are more likely to see familiar people in the parks, and use the parks more when there are more staff present.
Cohen, D.A., Han, B., Derose, K.P., Williamson, S., Marsh, T., Rudick, J. and McKenzie, T.L., 2012. Neighborhood poverty, park use, and park-based physical activity in a Southern California city. Social Science & Medicine 75(12): 2317-2325.