Data on air pollution of the Hungarian grasses are no available. The most results have been published about the toxic and heavy metals settling by dust to the surface of plants. The level of lead pollution deriving from transportation is gradually decreasing moving away from the roads. Plants possessing big and sticky leaf surfaces contain higher concentration of leads. At least half of the lead content of plants derives from settling dusts. This has been proven by washing them away the plants. The rainfall contains the toxic substances in high concentration and these substances will accumulate in the segregation pool of the roadside. After intorduction of the use of unleaded petrol the lead content of the roadside plants has decreased. Recently in Hungary the sulphur dioxide content of the air drastically while that of the other acidic substances moderately decreased. So the acidic settling does not cause further environmental problem.