Distribution characteristics of PM 2.5, NO 2, CO levels and concentrations on roads in Xi'an City
To obtain the horizontal concentration distribution characteristics of PM2.5, NO2, and CO on roads in Xi'an City, Xiaozhai and Qinling Ring Road were selected as representatives of urban and suburban roads in Xi'an City. The horizontal distribution monitoring method was used to obtain the horizontal concentration distribution characteristics of each road at 0, 15, and 50 meters away from the road edge ρ (PM2.5) ρ (NO2) and ρ (CO). The results indicate that compared to the Qinling Huanshan Road (hereinafter referred to as Qinling), the observation point of Xiaozhai in the urban area has ρ (PM2.5) ρ (NO2) and ρ (CO) are (88 ± 50) and (78.6 ± 29.8) respectively μ Both g/m3 and (1.5 ± 0.3) mg/m3 are higher than the mass concentrations of the three in the Qinling Mountains [55 ± 23) and (47.9 ± 19.8), respectively] μ G/m3 and (1.4 ± 0.1) mg/m3. In terms of spatial distribution, ρ (PM2.5) ρ (NO2) ρ (CO) The horizontal gradient distribution is obvious. Compared with the 0 m distance from the road edge, Xiaozhai ρ (PM2.5) decreased by 6.48% and 7.96% at distances of 15 and 50 meters from the road edge, respectively, while the Qinling Mountains decreased by 5.45% and 9.09%; Xiaozhai ρ (NO2) decreased by 8.57% and 14.29% at 15 and 50 meters, respectively, while the Qinling Mountains decreased by 15.45% and 24.89%; At a distance of 50 meters from the edge of the road, Xiaozhai ρ (CO) decreased by 25.00%, while Qinling Mountains decreased by 25.00% and 41.67% at distances of 15 and 50 meters from the road edge, respectively. Research shows that PM2.5, NO2, and CO from motor vehicle emissions have a significant distance effect on both sides of the road, and the horizontal decrease of observation points in suburban areas is more pronounced