Air quality will be unhealthy in downstate New York and parts of Pennsylvania Saturday and residents are advised to stay home, transportation officials say. The New York and Pennsylvania state department of transportation officials say Saturday is an Air Quality Action Day, a day when air quality will be unhealthy, especially for children, seniors and people with asthma and other respiratory ailments, due to forecast high levels of ground-level ozone pollution. This alert is issued for parts of the New York downstate metropolitan region -- the five boroughs of New York City, Long Island and lower Hudson Valley -- and these residents are asked to leave their cars at home and/or stay indoors as much as possible. In Pennsylvania, air quality action day predicts Saturday to have unhealthy pollution levels for sensitive people in the Liberty-Clairton region in Allegheny County; the Philadelphia region; the Susquehanna Valley region of Cumberland, Dauphin, Lancaster, Lebanon and York counties; and the Lehigh Valley region of Berks, Lehigh and Northampton counties. Pennsylvania officials say ground-level ozone -- which forms when pollution from vehicles, industry, households and power plants \"bakes\" in the hot sun -- makes it hard for some to breathe. New York officials also ask these residents to: Use public transportation. Refuel after dark because this prevents some pollutants from being emitted into the air and reacting with sunlight. Avoid operating gas-powered gardening equipment such as lawn mowers.