Effects of traffic and urban parks on PM ₁₀ and PM _2.5 mass concentrations

Effect of Road Traffic on Air Pollution. Experimental Evidence from COVID-19 Lockdown

“…In recent years, many cities have undergone a worsening in air quality [1][2][3], due to the increasing concentration of human activities, which produce polluting emissions [4][5][6]. For instance, throughout Italy in 2018, the percentages of stations monitoring air quality, which exceeded the limits set by the World Health Organization (WHO) [7] in terms of average annual concentrations of NO 2 and average daily concentration of PM 10 , were about 6% and 75%, respectively [8].…”

Effect of Urban Greening on Incremental PM2.5 Concentration During Peak Hours

“…Based on the refined monitoring data, this study screened out the concentration changes of PM 2.5 in specific time periods to eliminate the interference of background concentration and spatial spillover effect, ensuring that the samples are comparable. Validation of this practice has been performed in other studies (11,13,38). We believe that the use of PM 2.5 increment instead of original concentration has the following advantages: Firstly, to our knowledge, no cross-sectional study has yet investigated the main emission sources of PM 2.5 at different times of the day, the present study was designed to begin filling the gap; Secondly, compared with the original concentration, the sudden increase of particulate matter concentration during the peak hours is obviously more related to human activities, mainly commuting traffic, more likely to take feasible measures for improvement.…”

“…Related studies have found that the PM 2.5 contribution of transportation to average mass concentration can be 25-50% (28)(29)(30), other sources also include industrial activities (including electricity generation, industrial fuels) (31,32), coal burning and biomass combustion for cooking (33), winter heating (34), construction (35), and other specific activities (setting off fireworks & open straw burning) (36,37). Any attempt to statistically evaluate the strength of association between urban elements and PM 2.5 pollution will be complicated by a range of confounding factors (7), thus data screening should be undertaken in studies of daily PM 2.5 concentrations to screen for specific pollution events (11,13,38). Figure 1 shows the distribution of PM 2.5 concentration increase per hour from UTC+7 time zone to UTC+9 time zone 1 http://106.37.208.233:20035/ for a total of 283 cities (Karamay and Urumqi, the only two cities in UTC+6 time zone are not considered) (The detailed average hourly trends of PM 2.5 concentration in each city are shown in Figure S1).…”

“…At a finer spatial scale, a series of methods and tools, such as remote sensing (8)(9)(10), field measurements (11)(12)(13), Geographical Information Systems (GIS) (10), and landscape analysis software (8), had been used for analyzing urban morphology (building layout, road patterns, land uses, and green space) and its relationship to haze pollution, aims at reducing PM 2.5 concentrations and minimizing human exposure to particulate matter. A study conducted in the United Kingdom showed that green infrastructures are beneficial but they do not represent a solution to completely remove air pollution from cities, while working on removing street pollution via dispersion proved to be as or even more efficient than deposition technologies (12).…”

The Effect of COVID-19 Pandemic on Emitted PM2.5 in Urban Road Networks: Using Loop Data and Kriging Method for Passenger Cars in the Central Part of the City of Lodz

“…Third, due to the delays that might be occurred in the data collection process, temporal records are associated with lags which add more complexity to the vehicular pollution emission analysis (Shi et al, 2018;Rossi et al, 2020). Nevertheless, regarding the fact that models provide helpful tools to estimate pollution concentration and dispersion (Holnicki et al, 2016;Khan and Hassan, 2020), vehicular emissions have been computed in various studies (Jenkins et al, 1970;Clougherty et al, 2008;Elangasinghe et al, 2014;Perez-Martinez and Miranda, 2015;Pan et al, 2016;Shi et al, 2018;Qu et al, 2019). These studies calculated the vehicular emissions by focusing on the flow data collected for a subset of links (e.g., a certain road or highway) in a network.…”