Impact of traffic densities on indoor air quality

Abstract

In the last few decades air pollution in general and indoor air pollution in particular represents a danger for the human health. The impact of traffic density on indoor air quality was evaluated. Indoor and outdoor concentrations of particulate matter (PM10), nitrogen dioxide (NO2) and sulfur dioxide (SO2) were estimated in 30 homes during the winter and summer seasons of 2016. The results showed that the impact of traffic on indoor concentration was evident in moderate and high traffic areas. PM10 recorded the highest values in winter while both NO2 and SO2 were slightly higher in the summer for all the studied areas. PM10 is one of the most commonly used criteria for determining air quality indices (AQI). Among the different studied sites, the highest traffic density showed the worst air quality (AQI>395). The other sites showed very poor air quality (AQI>224) which showed that these areas were also polluted. In winter, the levels of indoor bacteria at all sites were lower than the threshold value (TLV), 50 CFU/m3 according to the WHO, but the opposite was observed in the summer. It was also found that the counts of indoor Gram-negative bacteria were less numerous than Gram-positive bacteria. The quality index for each individually studied site and AQI in this region of Cairo was higher than the allowable value of the air quality standard set by the US Environmental Protection Agency and the Egyptian Ministry of Environment.