According to the Environmental Protection Agency, “indoor pollution levels appear to be controlled primarily by outdoor concentrations” (link provided below).
The “Environmental Health Perspective” discusses the nature of ambient air pollution in the Arabian Peninsula. It is characterized by “dust storms, high levels of desert particulate matter (PM), transportation and industry-related emissions, and meteorology-linked smog formation”. These ambient air pollutants “may infiltrate and contribute to indoor air pollution”.
Markers of infiltration from outdoor air sources include SO2, H2S, NO2, HCHO, and PM). All have been linked with respiratory disease symptoms. HCHO and CO have been associated with neurologic symptoms.
A study of 628 households in the United Arab Emirates has shown that these outdoor air pollutants have indeed infiltrated our households. Participants in households with quantified SO2, NO2, and H2S (measured concentrations above the limit of quantification) were twice as likely to report doctor-diagnosed asthma. Participants in homes with quantified SO2 were more likely to report wheezing symptoms and speech-limiting wheezing. Do you want these pollutants to infiltrate your home? The respiratory effects can be deadly.