Grasses are widespread covering about 20% of the world's surface. They release pollen into the air which is inhaled by you. If you have a tendency to develop allergies, you can suffer from grass allergy when you take a walk in the park or go close to freshly cut grass. Symptoms include stuffy nose, itchy throat, mouth, skin & eyes, headache, sinus pressure and coughing. You should shower & change your clothes when you come from outside. You should also keep the windows closed to prevent grass pollen from entering your house.