Table 4.

Pico table of screening criteria for titles and abstracts

Criterion	Guidance notes	Decision
1. Year	No restriction on date
2. Study design	To include: cross-sectional studies, case-control studies, longitudinal observation studies (prospective and retrospective cohort and longitudinal studies) and systematic reviews (meta-analysis/reviews/reviews of reviews)
3. Type of participants	Studies involved children aged 0–5 years old
4. Health outcomes	The study focused on pneumonia as the primary health outcome
5. Exposure	Does the study look at indoor air pollution as primary exposure