Why photosynthesis is slower in plants growing near a cement plant?

For photosynthesis, a plant needs water, light, carbon dioxide and chlorophyll, which is directly in the plant. If water enters the body through the roots, then carbon dioxide is fixed by the plant leaf. Fixation of CO2 is possible due to the presence of stomata on the surface of plants – these are small holes that can open and close (they are also involved in the process of water evaporation). If a plant grows next to a cement plant, then its leaves are covered with a layer of dust, which prevents the penetration of carbon dioxide into the body, and therefore, photosynthesis will not be as intense as in a plant in a normal environment. Moreover, groundwater can be polluted with waste from factories, which will negatively affect the condition of the plant.