# A Review of Indoor Air Quality in Social Housing Across Low- and Middle-Income Countries
## 3 Results of the Literature Survey
### Health and Comfort (H&C)  
Studies in this category identify the health impacts of poor IAQ and the potential interventions to improve health and comfort in social housing settings. In affordable housing in Mumbai, India, [PERSON] and [PERSON] [35] observed generally low indoor air velocities (0.1 to 0.5 m/s), with 35% of residents supporting increased air movement  
Figure 3: Global map of the investigated low- and middle-income countries (LMICs) included in the reviewed studies (highlighted in red). Other LMICs (dark gray) and higher income nations (light gray) are included for comparison to show the focus on diverse geographic regions.  
to promote evaporative cooling. [PERSON] et al. [36] further researched the impact of urban densification on Mumbai's low-income _chavls_ (i.e., affordable housing) using CFD and validated their results using wind tunnel experiments to assess indoor air pollution, natural ventilation, and daylighting. Their study revealed that redevelopment plans designed to increase density worsened IAQ and reduced daylight exposure. The study highlighted significant health concerns, including asthma, tuberculosis, and pneumonia, due to inadequate ventilation, as well as mental health risks like seasonal affective disorder (SAD) and vitamin D deficiency caused by insufficient daylight. The authors proposed a revised design scheme that improves airflow and daylight exposure without the need for extensive demolition, underlining the importance of thoughtful architectural design in ensuring the health and comfort of residents in densely populated areas.  
An investigation of Malaysian social housing, by [PERSON] and [PERSON] [37], found elevated levels of 24 h average concentrations of PM2.5 (44.2 \(\mathrm{\SIUnitSymbolMicro m}^{3}\)) and PM10 (53.5 \(\mathrm{\SIUnitSymbolMicro m}^{3}\)). Their experimental design of a dynamic hybrid air-permeable ceiling (DHAPC) system achieved a significant reduction in particulate matter, where recycled glass insulation materials, in combination with an activated-carbon filter, enabled a 98% decrease in PM2.5 and PM10 levels by filtering airborne particles, moisture, and heat, improving both respiratory health and thermal comfort. A study in Kampala, Uganda [38], further showed how natural ventilation (NV) significantly improved IAQ (r = 0.752) and was positively correlated with health improvement (path coefficient = 0.19), suggesting that for every unit improvement in IAQ, occupant health increased by 0.19 units. A study by [PERSON] et al. [39] reported elevated carbon monoxide (CO) concentrations in Bogota, Colombia, with peaks as high as 150 ppm, linked to the use of natural gas appliances in households across various incomes. However, low-income households were statistically more vulnerable due to the use of older appliances and poor ventilation, with CO concentrations up to five times higher than in higher-income homes. Lastly, research in Indonesia [40] linked issues like multiple chemical sensitivity and respiratory problems to elevated levels of formaldehyde (mean: 0.073 ppm; maximum: 4.802 ppm) and total volatile organic compounds (TVOCs) (mean: 10.12 mg/m\({}^{3}\); maximum: 91.90 mg/m\({}^{3}\)) in newly constructed affordable apartments, suggesting that risks were due to modern building materials and inadequate ventilation.