I'm not referring to work hazards, that is obvious. Health hazards that cannot be denied unless you have opposing information, there is none. Direct exposure in general, no matter the amount of time. It only takes a single inhalation for a chance of a particulate to enter your lung and fester. You don't have to be working to breathe it and you are trying to tell me that standing behind a commercial jet taking off at full throttle shooting out hundreds of chemicals and carbon at an enormous rate is safe to do for short periods... Please think about this.