What are the major indoor air pollution problems and how do we address them?
a) Mold, radon, carbon monoxide; improve ventilation, use air purifiers, and maintain appliances
b) Dust, pet dander, pollen; clean regularly, use dehumidifiers, and avoid using chemicals indoors
c) Smoke, volatile organic compounds, lead; ban smoking indoors, use natural cleaning products, and remove lead paint
d) All of the above