Ambrosia pollen contains strong allergens. Allergic reactions can also be caused by direct contact with the plant. The investigations of the dynamics of Ambrosia pollen seasons were conducted in Lublin (Poland) and Ivano-Frankivsk (Ukraine) in 2013–2015. The onset and end of the seasons, maximum concentrations, annual sums, and the number of days with an allergy risk were determined. Additionally, the types of trichomes present on different parts of Ambrosia artemisiifolia L. shoots were determined using light microscopy. Morphometric studies were carried out on trichomes sampled from staminate inflorescences. The maximum concentrations and annual sums of Ambrosia pollen were shown to be substantially higher in Ivano-Frankivsk than in Lublin. Similarly, the risk of allergies is higher in the study site in Ukraine. The study results indicate that the presence of Ambrosia pollen grains in Lublin may be associated with long-distance transport. The presence of non-glandular and glandular trichomes was found on the examined organs. The staminate inflorescences were covered by two types of non-glandular trichomes (short and long) and two types of glandular trichomes (linear and biseriate), whose secretory product can cause dermatitis in sensitive subjects upon contact with the plant.