New Delhi: A recent study has revealed that the air inside many homes in Delhi is nearly as hazardous as the city’s outdoor smog. The research found extremely high levels of fungal and bacterial particles in indoor environments, raising serious public health concerns.

Alarming levels of indoor pollutants

The joint study, conducted by Delhi University’s Satyawati College, Jamia Millia Islamia, and South Dakota State University, analysed air quality in 336 households across densely populated areas of North Delhi. Researchers found:

  • Fungal spore concentrations up to 12 times higher than the World Health Organization’s safety limits.
  • Bacterial concentrations up to 10 times higher than recommended levels.
  • Most fungal particles were smaller than 2.5 microns, making them capable of reaching deep into the lungs.

Seasonal trends and causes

Air sampling across all four seasons showed that fungal levels peaked in the fall (September–November), while bacterial loads were highest in summer (August). Poor ventilation, damp walls, and overcrowded spaces were identified as key contributors to the high microbial load indoors.

Health impact on residents

The study also surveyed residents’ health:

  • 33% reported frequent headaches
  • 23% experienced eye irritation
  • 22% suffered from persistent coughing or breathlessness
  • 18% reported sneezing or allergic rhinitis
  • 15% experienced skin irritation or itching

Children and young adults were particularly affected, with around 28% of children and 25% of young adults showing respiratory or allergy symptoms. Women reported a higher incidence of dermatological and eye complaints due to prolonged indoor exposure.

Implications for public health

Experts warn that indoor microbial pollution can be as harmful as outdoor air pollution. The study highlights the urgent need for improved ventilation, humidity control, and regular cleaning in homes, especially in densely populated urban areas. Small airborne particles can penetrate deep into the respiratory system, increasing the risk of chronic respiratory illnesses.