The effects of ventilation and building characteristics on indoor air quality in waterpipe cafes

To determine the concentration of carbon monoxide (CO) and particulate matter (PMs), indoor air samples were collected from 60 waterpipe cafes in Ardabil city of Iran. Moreover, the influence of several structural, operational, and ventilation system were evaluated on the concentration of the selected pollutants. The results showed that the mean concentration of CO (12.0 +/- 7.2 mg/m(3)) and PMs (PM1 = 171.5 +/- 119.6 mu g/m(3), PM2.5 = 303.3 +/- 201.9 mu g/m(3), PM10 = 440.3 +/- 272.2 mu g/m(3)) were notably higher than the guideline levels. According to the results, open face/cafe area was influenced by the natural ventilation rate and the mean air exchange rate was 3.1 +/- 1.1 min(-1). The natural ventilation has a functional role on air quality of the cafes, and fan-type mechanical ventilation was influencing factor on CO concentration when the natural ventilation was restricted. "Type of used charcoal" had the highest influence on the releasing of pollutants inside the cafes as the pollutant concentrations were lower for simple (raw) charcoal compared with the favored (aromatic) one. The results indicated that the building characteristics and natural ventilation considerably affect air quality of the cafes.