It could happen that you will not be able neither to see nor to sense anything unusual. During a dangerous biological or chemical event the proper authorities will provide you with all the necessary instructions. You may be asked to: evacuate, go to a higher situated area, stand against the wind blow, stay at the apartment or to go into a certain place. You may also find yourself very close to the dangerous event and not realise that. If you will see people vomiting, in convulsions or disoriented you should immediately notify the medical care, and leave the place looking for a medical assistance.