Because dry ice releases carbon dioxide, it can be hazardous to humans in a closed-off area. Make sure plenty of fresh air is getting into the room where the dry ice is being stored. Otherwise, it can cause asphyxiation in humans and animals. Remember, a closed car is an unventilated  area, especially if the air is not on. Don't leave dry ice in a parked, closed car. When transporting it, open the windows, or make sure you set the air conditioner to bring in fresh air. In addition, place it away from you when you're driving. Dry ice sublimates instead of melts, meaning it releases carbon dioxide. As carbon dioxide changes to gas, it needs room to escape. If you use an airtight container, the gas cannot escape. In extreme cases, the gas can expand too much, causing an explosion. A freezer is airtight, and it can cause the dry ice to explode. Also, if you try to put dry ice in a regular freezer or refrigerator, you could destroy the system, as the thermostats are not made to handle those kinds of temperatures. If you plan on breaking up a block of dry ice, you should wear safety goggles and a face shield to protect your eyes. Otherwise, shards of ice can fly into your eyes and cause burns. Carbon dioxide tends to sink in rooms, as it is heavier than the air you breathe. Therefore, it will collect in low areas. Don't intentionally stick your head in those areas. Dry ice can damage many surfaces due to its extreme temperatures. For instance, you can crack tile or other counter top surfaces by placing dry ice on it. The best way to get rid of unused dry ice is to let the unused portion continue to sublimate. Make sure the area is well ventilated while the dry ice continues to disappear. Don't put dry ice down a sink or in a toilet, as you may destroy them. Similarly, don't put dry ice in a trash can or leave it where it can accidentally be picked up or touched by someone who doesn't know it's dry ice, as it can burn them.

===
Write a summary of the previous text in Chinese:
将干冰保存在通风良好的地方。 不要使用密闭容器。 不要将干冰放在冰箱里。 将干冰凿碎时，应戴上护目镜和护面罩。 不要到低处去。 注意放置干冰的表面材料。 妥善处理没用完的干冰。