Description suggests it might be a pingecula. You have not mentioned, for long it has been there. If your work involves lot of outdoor work, better be careful while working outdoors by restricting time exposed to sunlight and dusty environment
Next Steps
if no symptoms, like watering, redness, and not increasing in size, you can wait and watch. if any change occurs, you can consult eye specialist
Health Tips
wear uv filtering glasses, and a peak cap to reduce sunlight damage to eyes, especially the white part where the spot appeared.
very unlikely, it is a Bitot's spot. it appears frothy.