Coastal areas and the areas near the sea because of the dirty water agricultural groundwater. Salts from the fertilizer with cement and air will cause efflorescence.
Coastal areas and areas near agricultural sources. The sea water from dirty water, salt, cement and fertilizers, when exposed to the air. Cause stains white.
The area near the seashore and agriculture, because sea water dirty. Groundwater salt hot กปุ๋ย upon contact with the cement and the air. Will cause stains white.