oa Chemical Characterization of Indoor and Outdoor PM2.5, PM10 and VOCs in a Public Building in Doha City, Qatar

It is a fact that people spend 60-90% of their lifetime indoors; nevertheless, in case of Middle Eastern countries this percentage can reach 100%, especially during summer and dust storms periods. Indoor air quality (IAQ) is of great importance for peoples’ health, especially for vulnerable population groups. To the best of our knowledge, recent air quality studies in areas with hot and arid climate such as Qatar (or Middle East Area in general), are limited. Especially for the indoor environment, there is lack of indoor sources identification and consequently there are insufficient mitigation actions. This study aimed to assess the IAQ in an air-tight public building during warm season. For this scope, a monitoring campaign of particulate matter (PM2.5 and PM10) and volatile organic compounds (VOCs) for both indoor/outdoor measurements was performed at the Supreme Council of Health building in Doha, Qatar. The duration of the campaign was from 22/4/2015 to 21/6/2015. Chemical analysis for organic/elemental carbon (OC/EC), ions (NO3 ⁻ , SO4 ^2 − , Cl⁻ , Br ⁻ , NH4 ⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺) and elements (Cu, Pb, Cr, Ni, Cd, Zn, Fe, Al) was conducted on the collected particle mass. Results showed that OC and EC outdoor values were higher (by 3-4 times) than the indoor ones for both PM fractions. Outdoor average OC value was 12.7 and 16.3 μgm^− 3 for PM2.5 and PM10 respectively. Among the elements analyzed, Zn dominated in indoor samples followed by Mn, Ba, Pb while outdoors, Sr and Mn were the most abundant species. Concerning ions, indoor to outdoor ratio (I/O), was in all cases lower than unity implying the prevalence of outdoor sources emissions. Finally, I/O was close to unity for VOCs except for xylene and dlimonene, which were significantly higher indoors implying the existence of internal emission sources.