Atlanta granite geology and radon

Granite Geology & Radon in Atlanta

Why Metro Atlanta Has Elevated Radon Potential

Atlanta's granite bedrock naturally contains uranium, which decays into radon gas. Learn about the geology-radon connection.

Atlanta's Geological Setting

Piedmont Province

Atlanta sits in the Piedmont geological province, characterized by ancient crystalline rocks including granite, gneiss, and schist.

Uranium Content

Granite and similar rocks naturally contain trace amounts of uranium-238, which is the parent element of radon in the decay chain.

Radon Formation

As uranium decays through radium-226, it produces radon-222 gas, which can migrate through soil and enter buildings.

Stone Mountain

Stone Mountain is one of the largest exposed granite formations in the world, illustrating the type of rock underlying much of Metro Atlanta.

The Radon Decay Chain

Uranium-238
Naturally occurs in granite
↓ decays to
Radium-226
Intermediate decay product
↓ decays to
Radon-222
Radioactive gas that enters homes

The Bottom Line

While granite geology creates conditions for radon production, individual home levels depend on many factors. Understanding the geological source helps explain why testing is important in Metro Atlanta, but testing is the only way to know your specific home's radon levels.

Granite & Radon FAQs

Why does granite produce radon?

Granite naturally contains trace amounts of uranium-238. Through radioactive decay, uranium transforms into radium, which then decays into radon-222 gas. This radon can migrate through soil and enter buildings through foundation openings.

Is all of Atlanta on granite?

Much of Metro Atlanta sits on the Piedmont geological province, characterized by granite and similar crystalline rocks. However, geology varies locally. Some areas have different rock types or soil compositions, but granite-derived soils are common throughout the region.

Does living near Stone Mountain increase radon risk?

Stone Mountain illustrates the type of granite underlying much of Metro Atlanta, but proximity to the mountain itself doesn't determine home radon levels. Radon levels depend on local soil conditions, foundation type, and how your specific home interacts with the ground beneath it.

Can you see evidence of granite in Atlanta soil?

Yes. The characteristic red clay soil common in Metro Atlanta is derived from weathered granite and similar rocks. This soil still contains minerals that produce radon, which is why testing is important even though bedrock may be deep underground.

Do granite countertops contribute to indoor radon?

Studies have found that granite countertops typically contribute negligible amounts to indoor radon levels compared to soil gas entry. The primary radon source in most homes is the soil beneath the foundation, not interior stone materials.

Are other Georgia regions also affected?

Yes. The Piedmont and Blue Ridge provinces extending from Metro Atlanta through North Georgia share similar granite geology. Radon potential exists throughout these regions, though individual home levels vary.

Test Your Home

Contact us to discuss radon testing for your Atlanta-area home.

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