Assessment of indoor air pollutant concentrations and emissions from natural gas cooking burners in residential buildings in Tehran, Iran

The effect of natural gas cooking burner usage on time-dependent concentrations of carbon monoxide (CO), nitrogen dioxide (NO 2 ), and formaldehyde (HCHO) in homes in Tehran was estimated using a mass balance model. The outdoor air concentrations were considered the only background sources of indoor concentrations of CO and NO 2 , and indoor concentration of HCHO was calculated without considering any background sources. The contributions of the natural gas cooking burner use to the indoor concentrations of CO and NO 2 in the residential buildings were significantly affected by season and municipal region and estimated to be 13% (95% uncertainty interval (UI) 8–42) and 26% (15–45), respectively. The annual average indoor concentrations of CO, NO 2 , and HCHO in the residential buildings were 3431 (2308–6863), 87 (56–169), and 3 (1–20) μg/m 3 , respectively. Although the average indoor concentrations of all the pollutants were within the permissible range, the upper limits of 95% UI of 24-h average CO and 1-h average NO 2 concentrations were higher than the WHO guidelines in 41% and 25% of the cases, respectively. The most efficient measures for control of people’s high exposure to the pollutants from natural gas burners were determined to be partial or total replacement of natural gas burners with electric burners, using the range hood during cooking, reducing frequency and duration of natural gas burner, optimizing ventilation rate, and increasing people awareness about air pollutants emitted by natural gas burners that should be taken with more consideration.