Your description of an older villa in Al Qusais with constant dampness, even with AC, is a classic scenario. Dubai’s high humidity, combined with potential thermal bridging in older construction and condensation behind curtains or furniture, creates perfect conditions for mold. The persistent child coughing is a significant indicator that environmental factors should be investigated.

For a verifiable diagnosis, insist on a methodology that includes both surface and air sampling. The surface sample from the curtain wall will confirm if it’s active mold (like Aspergillus or Cladosporium, which are common here) and not just dirt. The concurrent air test measures the spore count your children are breathing, which is critical for understanding the health risk. A reputable provider should be able to provide preliminary findings on-site and a detailed, lab-cultured report within 48-72 hours.

While DIY test kits are sold, they are not recommended for your scenario. The collection is error-prone, and the shipping and external lab analysis can take weeks, delaying any necessary remediation for your children’s health. A professional inspection is the swiftest path to a definitive answer and a clear remediation plan.