Are there DIY radon mitigation options, or is it always necessary to hire a professional?

I've discovered high radon levels in my home and I'm wondering about DIY radon mitigation options versus hiring a professional. Are there effective DIY methods for reducing radon levels, or is it always necessary to bring in a professional? What are the pros and cons of each approach, including considerations like cost, effectiveness, safety, and any potential impacts on home resale value?

Radon often enters homes by seeping out of the ground. Opening windows may lower the concentration of radon in the home.

If the home has a crawl space, then adding vents in the crawl space can lower radon levels inside. If it has a basement, leaving a window open in the basement can lower radon levels in the main living area. You could get more proactive, by leaving a bathroom ventilation fan running constantly in the basement with a window cracked in the main living area.