Mold Exposure: This is a common issue in homes, especially in areas with high humidity or water damage. Mold spores can become airborne and be inhaled, leading to respiratory symptoms such as coughing, particularly in the morning when the air is more stagnant.

Dust Mites: These tiny creatures thrive in bedding, carpets, and upholstered furniture, and their waste products can become airborne, triggering allergic reactions and coughing.
Pet Dander: For households with pets, dander (small scales that fall off the skin of animals) can be a significant allergen, leading to morning coughing among other symptoms.
Secondhand Smoke: Exposure to smoke from cigarettes, cigars, or pipes can irritate the lungs and cause coughing, especially in enclosed spaces like homes.
Poor Ventilation: Inadequate exchange of indoor and outdoor air can lead to the accumulation of pollutants and moisture, creating an environment conducive to mold growth and exacerbating respiratory issues.

Carbon Monoxide Poisoning: Although less common, carbon monoxide (CO) poisoning from faulty heating systems, generators, or idling cars in attached garages can be deadly. CO can cause coughing among a range of other symptoms, including headache and dizziness.
Radon Exposure: Radon is a radioactive gas that can accumulate in homes, particularly in basements and crawl spaces. Long-term exposure is a known risk factor for lung cancer, and while it may not directly cause morning coughing, it's a critical hazard not to miss.
Asbestos: In older homes, asbestos can be present in insulation, flooring, and ceilings. When disturbed, asbestos fibers can become airborne and lead to serious lung diseases, including cancer.

Volatile Organic Compounds (VOCs): While not uncommon in household products and materials, VOCs can cause a range of health issues, including respiratory problems. However, they are less likely to be the primary cause of daily morning coughing compared to other factors.
Household Pesticides: Exposure to pesticides used in the home can lead to respiratory symptoms, but this would typically be associated with a history of recent pesticide use.
Formaldehyde: Found in some building materials and household products, formaldehyde can irritate the eyes, nose, and throat, and cause coughing, but significant exposure leading to daily morning coughing would be unusual in a typical home environment.