Underway monitoring device and traceability method for particle size spectrum emission potential of road raised dust

Abstract

The invention discloses an underway monitoring device for the particle size spectrum emission potential of road dust, and the device comprises a particulate matter collection unit which comprises two sampling pipelines, a dust sampling port of one sampling pipeline is located behind a front right tire, and the particulate matter collection unit is used for collecting suspended pavement particulate matters of rotating tires in the running process of a motor vehicle; a background point sampling port of the other sampling pipeline is located at the top of the experimental vehicle, and a particulate matter sample in environment background air is detected to be compared with pavement particulate matters collected by the raised dust sampling port; the vacuum pump provides power for the sampling head; the particle size spectrum monitoring unit is used for detecting particle size spectrum concentration of particles in air; the auxiliary unit is used for providing meteorological parameters of weather; the data acquisition and transmission unit is used for data acquisition and transmission. The invention provides an efficient, safe and rapid method for establishing the particle size spectrum of the road dust particles.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection, and in particular to a cruise monitoring device and a source tracing method for emission potential of road dust particle size spectrum. Background Art

[0002] With the continuous upgrading of economic and social activities and the acceleration of urbanization, the natural environment faces severe challenges in greenhouse gas emissions and atmospheric environmental quality.

[0003] Road dust contributes greatly to atmospheric particulate matter and is an important factor affecting air quality and human health. Particle size analysis of road dust particles can provide a deeper understanding of the emission characteristics of road dust and establish a more refined emission inventory. Monitoring the emission characteristics of road dust particle size spectrum, building a road dust emission inventory and conducting source analysis can provide theoretical support for road dust pollution control technology and air quality improvement in the region.

[0004] Traditional monitoring of dust emissions from urban paved roads is to collect dust samples from the road and then analyze them to obtain the characteristics of dust pollution on urban paved roads. Collecting dust on roads in a static state cannot reflect the actual situation of dust emissions generated by dust on urban paved roads during the driving of motor vehicles, and has certain limitations. Summary of the invention

[0005] The purpose of the present invention is to provide a cruise monitoring device and a source tracing method for the emission potential of road dust particle size spectrum, so as to solve the technical problems existing in the existing prior art.

[0006] To achieve the above-mentioned object, the present invention provides a cruise monitoring device for road dust particle size spectrum emission potential, comprising: a particle collection unit, a vacuum pump, a particle size spectrum monitoring unit, a vehicle positioning system, an auxiliary unit, a power supply unit and a data collection and transmission unit, wherein:

[0007] The particle collection unit includes two sampling pipelines. The dust sampling port of one sampling pipeline is located behind the front right tire to collect the road particles suspended by the rotating tire during the driving of the motor vehicle. The background point sampling port of the other sampling pipeline is located on the top of the experimental vehicle to detect the particle samples in the ambient background air for comparison with the road particles collected by the dust sampling port.

[0008] A vacuum pump, which provides power for the sampling head and collects dust particles in the sampling pipeline. The vacuum pump is equipped with a motor or is independent without a motor;

[0009] The particle size spectrum monitoring unit includes a particle size spectrum monitor 1 and a particle size spectrum monitor 2, which are used to detect the particle size spectrum concentration of the particles in the air;

[0010] The vehicle positioning system is used to locate the vehicle;

[0011] The auxiliary unit is used to provide meteorological parameters of weather;

[0012] The data acquisition and transmission unit is used for data acquisition and transmission;

[0013] The power supply unit includes a power supply and a single-phase high-pressure fan, which provide power for the entire detection system, and adjusts the sampling flow in the sampling pipeline through a flow controller and a flow probe in the sampling pipeline, thereby controlling the gas velocity at the sampling inlet and minimizing the impact of non-constant speed sampling on particulate matter.

[0014] The present invention also provides a vehicle-mounted mobile monitoring system for road dust, which is used for real-time monitoring of road dust particle size distribution, road area dust particle size spectrum emission potential measurement and road traffic dust particle size spectrum sampling, comprising:

[0015] Two sampling pipelines, one end of one sampling pipeline (4) is a sampling port, and the sampling pipeline (4) is provided with a vacuum pump, a flow rate measuring device composed of a flow controller (2) and a flow probe (3), a particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer (5), and a gas conveying device composed of a fan (1) in sequence along the gas flow direction; the other pipeline is connected to the particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer (7) for detecting the particle size spectrum concentration in the background air;

[0016] A data acquisition, transmission and processing system 11 and a global positioning system GPS device (8), wherein the GPS system (8) is connected to the data acquisition, transmission and processing system (11); the flow velocity measuring device, the particle size spectrum concentration measuring device, and the gas delivery device are all connected to the data acquisition, transmission and processing system (11); and the generator (12) provides power for the fan (1).

[0017] Furthermore, a sampling cup is arranged on the gas circulation pipeline of the particle size spectrum concentration measuring device. The sampling cup is hollow, and the inner diameter of one end is larger than the inner diameter of the other end. By placing different sampling cups, the gas flow rate of the gas circulation pipeline can be adjusted.

[0018] Furthermore, the EDM180 particle size spectrometer adopts the principle of laser scattering, and can simultaneously obtain the mass concentration values ​​of PM10, PM2.5, PM1 in the real road traffic environment and the road dust raised by the wheels, and the particle number concentrations of 31 particle size segments in the range of 0.25 to 32 μm.

[0019] The present invention also provides a vehicle-mounted mobile monitoring and tracing method using a road dust vehicle-mounted mobile monitoring system. The road dust particle size spectrum emission potential is a function of dust concentration and vehicle operation status. The vehicle-mounted mobile monitoring method performs numerical and particle size distribution characteristic analysis of the road dust particle size spectrum emission potential according to the function, wherein:

[0020] The conversion formula for the emission potential of road dust particle size spectrum based on the concentration value of multi-size particles is shown in formula (1). The cruise monitoring device can measure T and s in real time, where T is the concentration at the sampling point minus the background point concentration. The frequency of real-time measurement and recording of data can be in seconds or sub-seconds.

[0021] sL=a·d·e·T b ·s -c (1)

[0022] Where: sL ------- road dust particle size spectrum emission potential, g / m 2 ;

[0023] a-------Constant coefficient, the default value is 1.00, or it can be obtained by fitting measured data with multiple regression method;

[0024] -------Season coefficient, the default is 0.98 for spring, 1.03 for summer, 1.07 for autumn, and 1.18 for winter;

[0025] e--------Particle size coefficient, when the monitored particulate matter is PM2.5, take 1. When the monitored particulate matter is PM10, take 0.50 for urban roads, national roads and provincial roads, and take 0.47 for county roads and township roads;

[0026] -------Difference in particle concentration between sampling point and background point, mg / m 3 ;

[0027] b-------concentration coefficient, the default recommended value is 0.7752, and it can also be determined by the power exponent of the power exponential function relationship between concentration and emission potential obtained through experiments;

[0028] s-------Driving speed of the cruise monitoring vehicle, km / h;

[0029] c-------vehicle speed coefficient, the default recommended value is 1.8613, and it can also be determined by obtaining the power exponent of the power exponential function relationship between concentration and vehicle speed through experiments;

[0030] Formula (1) is used for the following analysis:

[0031] Step 1: Background particle size spectrum concentration distribution analysis;

[0032] Step 2: particle size spectrum and concentration analysis of particles raised by wheels;

[0033] Step 3: Particle size spectrum concentration analysis of road dust particles;

[0034] Step 4: Analysis of particle size spectrum concentration of dust particles on different types of roads and in different seasons;

[0035] Step 5: Analyze the potential spatial distribution characteristics of road dust diameter spectrum;

[0036] Step 6: Emission factor analysis of road dust particle size spectrum;

[0037] Step 7: Emission intensity analysis of road dust particle size spectrum;

[0038] Step 8: Analyze the spatial distribution of road dust particle size spectrum emissions.

[0039] Furthermore, the step 1 uses the spatial interpolation method of ordinary Kriging to obtain the spatial variation trend of the background mass concentrations of road dust PM1, PM2.5, and PM10 during the monitoring period.

[0040] Furthermore, the step 2 analyzes and obtains the spatial variation pattern of the wheel-raised mass concentrations of road dust PM1, PM2.5, and PM10 during the monitoring period.

[0041] Furthermore, the step 3 analyzes the spatial characteristics of the mass concentrations of road dust PM1, PM2.5, and PM10 during the monitoring period.

[0042] Furthermore, the step 5 uses the processing tools of ArcGIS software to visualize the emission potential of road dust particle size spectrum in each season.

[0043] Furthermore, in step 8, according to the vehicle flow and vehicle type distribution information, road network information, the AP model and the monitored dust particle size spectrum emission potential are used to calculate the emission factor, and ArcGIS software is used to calculate the emission amount, and a bottom-up road dust emission inventory of 500m×500m is established; the PM2.5, PM10 and TSP emissions of national roads, provincial roads, county roads, township roads and village roads are counted.

[0044] The method of the present invention has the following advantages:

[0045] The present invention uses a fast-moving road dust detection system to detect road dust in real time during vehicle driving, and can provide an efficient, safe and fast method for establishing a particle size spectrum of road dust particles. Through experimental data analysis, PM2.5 or PM10 detection data is stable and reliable in the vehicle-mounted mobile monitoring and tracing method.

[0046] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites the preferred embodiments and describes them in detail with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is the working flow chart of the monitoring device;

[0048] Figure 2 This is a schematic diagram of the vehicle-mounted mobile monitoring system;

[0049] Figure 3 This is a schematic diagram of the device for measuring the emission potential of road dust particle size spectrum;

[0050] Figure 4 Schematic diagram of the sampling cup structure

[0051] Figure 5 This is a schematic diagram of the spatial distribution characteristics of the background concentrations of PM1, PM2.5 and PM10 in road dust;

[0052] Figure 6 This is a schematic diagram of the spatial distribution characteristics of PM1, PM2.5 and PM10 wheel-raised dust in road dust;

[0053] Figure 7 This is a schematic diagram of the spatial distribution characteristics of PM1, PM2.5 and PM10 concentrations in road dust;

[0054] Figure 8 Schematic diagram of particle number concentration and mass cumulative percentage on different types of roads;

[0055] Fig. 9 This is a schematic diagram of the distribution of particulate matter mass proportions on roads of different grades;

[0056] Fig.10 This is a schematic diagram of the spatial distribution of the emission potential of road dust particle size spectrum;

[0057] Fig.11 This is a schematic diagram of the spatial distribution of road dust particle emission factors;

[0058] Fig.12 This is a schematic diagram of the spatial distribution of road dust particle emission intensity;

[0059] Fig.13 Schematic diagram of the spatial distribution of road dust particle emissions. DETAILED DESCRIPTION

[0060] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but those skilled in the art should understand that the embodiments described below are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] During vehicle driving, due to the friction between the tires and the road surface and the interaction of aerodynamic forces, the dust accumulated on the road surface will be discharged into the air in the form of particles. When the dust accumulated on the road enters the atmosphere under the action of mechanical or aerodynamic forces, a tail feather of particles will be formed behind the vehicle tires. The principle of the detection system is to detect the particle size spectrum of the particles at a fixed distance from the tires under known vehicle speed conditions and to simultaneously detect the particle size spectrum of the particles in the ambient background air to obtain the dust particle size spectrum difference. The road dust emission particle size spectrum potential and the dust particle size spectrum emission potential are calculated based on the dust particle size spectrum difference and the operating parameters of the detection vehicle. The dust particle size spectrum in the present invention refers to the tire dust particle size spectrum minus the particle size spectrum of the particles on the top of the vehicle.

[0062] The working principle of the cruise monitoring device for road dust particle size spectrum emission potential is as follows Figure 1 As shown in the figure, under certain test environment and operation requirements, the vehicle-mounted mobile monitoring system for road dust measures the road dust particle size spectrum, background particulate matter particle size spectrum, particle size distribution, vehicle speed and other parameters generated by vehicle driving or other disturbance methods, and outputs the road dust particle size spectrum emission potential data through model calculation, which is connected with the road dust dynamic control and effect evaluation refined management platform to realize real-time data access in seconds, GIS map display, over-standard push, summary statistics, system management and other functions, and connects with government management departments to effectively control road dust pollution.

[0063] The present invention provides a cruise monitoring device for the emission potential of road dust particle size spectrum, such as Figure 1 , Figure 2 and Figure 3 The cruise monitoring device for road dust particle size spectrum emission potential includes a particle collection unit, a particle size spectrum monitoring unit, a vehicle positioning system, an auxiliary unit, a power supply unit, and a data collection and transmission unit. The particle collection unit includes two sampling pipelines. The dust sampling port of one sampling pipeline is located at Figure 3 The dust sampling port is 50 mm in diameter and the background sampling port of another sampling pipeline of the particle collection unit is located at Figure 2On the top of the experimental vehicle shown, particulate matter samples in the ambient background air are detected for comparison with road particulate matter collected at the dust sampling port. The particulate matter size spectrum monitoring unit includes a particle size spectrum monitor 1 and a particle size spectrum monitor 2, which are used to detect the particle size spectrum concentration of particulate matter in the air. The vehicle positioning system is used to locate the vehicle. The auxiliary unit is used to provide meteorological parameters of the weather. The data acquisition and transmission unit is used for data acquisition and transmission. The power supply unit includes a power supply and a single-phase high-pressure fan, which provide power for the entire detection system, and adjust the sampling flow in the sampling pipeline through the flow controller and the flow probe in the sampling pipeline, thereby controlling the gas velocity at the sampling inlet and minimizing the impact of non-constant speed sampling on particulate matter. In order to meet the flow requirements of each particulate matter detection instrument, the gas flow in the sampling pipeline is designed to be 10m 3 / h; single-phase high-pressure fan, specific parameters are: power: 550W; frequency: 50Hz; voltage: 220V; maximum exhaust and suction volume: 100m 3 / h; rated suction pressure: -150mbar; rated exhaust pressure: 150mbar. A vacuum pump is used in the monitoring device (see Figure 1 ) provides power for the sampling head to collect dust particles in the sampling pipeline. The vacuum pump is equipped with a motor or is independent without a motor. The pressure reaches 0.17Mpa, the vacuum degree reaches -95Kpa, and the maximum flow rate reaches 76m 3 The power supply device composed of the generator 12 is a portable mobile power source to ensure the power demand of the system.

[0064] The present invention provides a vehicle-mounted mobile monitoring system for road dust, which is used for real-time monitoring of road dust particle size distribution, road surface dust particle size spectrum emission potential measurement (which can monitor road dust particle size distribution in real time) and road traffic dust particle size spectrum sampling.

[0065] like Figure 3As shown, a vehicle-mounted mobile monitoring system for road dust includes two sampling pipelines, one end of which is a sampling port, and a vacuum pump (not shown), a flow rate measuring device composed of a flow controller 2 and a flow probe 3, a particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer 5, and a gas delivery device composed of a fan 1 are sequentially arranged on the sampling pipeline 4 along the gas flow direction; another pipeline (not shown) is connected to the particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer 7, which is used to detect the particle size spectrum concentration in the background air. In addition to the above-mentioned devices, the vehicle-mounted mobile monitoring system for road dust also includes a data acquisition, transmission and processing system 11 and a global positioning system (GPS) device 8, and the GPS system 8 is connected to the data acquisition, transmission and processing system 11. The above-mentioned flow rate measuring device, particle size spectrum concentration measuring device, and gas delivery device are all connected to the data acquisition, transmission and processing system 11, and the generator 12 provides power for the fan 1. The amount of gas sucked by the particle size spectrum concentration measuring device is negligible compared to the total amount of gas in the sampling pipeline; and when the gas flow rate of the sampling pipeline changes, the amount of gas sucked by the particle size spectrum concentration measuring device should also change. Therefore, a sampling cup is set on the gas flow pipeline of the particle size spectrum concentration measuring device, see Figure 4 The sampling cup is hollow, and the inner diameter of one end is larger than the inner diameter of the other end. By placing different sampling cups, the gas flow rate of the gas flow pipeline can be adjusted.

[0066] The vehicle-mounted mobile monitoring system of the present invention uses the EDM180 particle size spectrometer to expand the test particle size, and can continuously monitor the number concentration of particles in road dust. The EDM180 particle size spectrometer uses the principle of laser scattering to simultaneously obtain the mass concentration values ​​of PM10, PM2.5, and PM1 in the real road traffic environment and the road dust raised by the wheels, and the particle number concentration of 31 particle size segments in the range of 0.25 to 32 μm. The combination of the vehicle-mounted mobile monitoring method and the EDM180 particle size spectrometer can provide an efficient, safe, and fast method for the establishment of the particle size spectrum of road dust particles. Through experimental data analysis, PM2.5 or PM10 detection in the vehicle-mounted mobile monitoring method has stable and reliable data, and PM30 (TSP) has a large variability. The relationship between PM2.5 and PM10 is analyzed as follows to provide a basis for model optimization and data application scenarios.

[0067] The cruise monitoring device for the emission potential of road dust particle size spectrum derives the numerical value and particle size distribution characteristics of the emission potential of road dust particle size spectrum by monitoring the concentration of dust particles detected by vehicle wheels and the monitoring data of vehicle operating status. That is, the emission potential of road dust particle size spectrum is a function of dust concentration and vehicle operating status.

[0068] The present invention provides a vehicle-mounted mobile monitoring and tracing method using a road dust vehicle-mounted mobile monitoring system. The road dust particle size spectrum emission potential is a function of dust concentration and vehicle operation status. According to the function, the numerical value and particle size distribution characteristic analysis of the road dust particle size spectrum emission potential are performed, including:

[0069] The conversion formula for the emission potential of road dust particle size spectrum based on the concentration value of multi-size particles is shown in formula (1). The cruise monitoring device can measure T and s in real time, where T is the concentration at the sampling point minus the background point concentration. The frequency of real-time measurement and recording of data can be in seconds or sub-seconds;

[0070] sL=a·d·e·T b ·s -c (1)

[0071] Where: sL ------- road dust particle size spectrum emission potential, g / m 2 ;

[0072] a-------Constant coefficient, which can be set to 1.00 by default, or obtained by fitting measured data with multiple regression method;

[0073] d------Seasonal coefficient, the default values ​​are 0.98 for spring, 1.03 for summer, 1.07 for autumn, and 1.18 for winter;

[0074] e--------Particle size coefficient, when the monitored particulate matter is PM2.5, take 1. When the monitored particulate matter is PM10, take 0.50 for urban roads, national roads and provincial roads, and take 0.47 for county roads and township roads.

[0075] T-------Difference in particle concentration between sampling point and background point, mg / m3;

[0076] b-------concentration coefficient, which can be determined by the recommended value of 0.7752 by default, or by obtaining the power exponent of the power exponential function relationship between concentration and emission potential through experiments;

[0077] s-------Driving speed of the cruise monitoring vehicle, km / h;

[0078] c-------vehicle speed coefficient, the recommended value 1.8613 can be used by default, or it can be determined by obtaining the power exponent of the power exponential function relationship between concentration and vehicle speed through experiments.

[0079] Step 1: Background particle size spectrum concentration distribution analysis

[0080] Figure 5The spatial variation trend of the background mass concentrations of PM1, PM2.5, and PM10 of road dust during the monitoring period obtained by the spatial interpolation method of ordinary Kriging is described. The results show that the background mass concentrations of PM1, PM2.5, and PM10 of road dust during the summer monitoring period are generally higher than those in winter. Regardless of summer or winter, the northern part is the area with high background mass concentrations. Among them, there is an uneven distribution of PM10 background mass concentrations in summer, and the concentration is high in different regions, indicating that coarse particles are common in the background of road dust. It may be that there are a large number of construction sites around the roads during the urban development period, and summer is the peak period of construction, which will lead to the phenomenon of high background concentration during monitoring. In winter, the background mass concentrations of PM1, PM2.5, and PM10 in road dust are relatively small. PM1 and PM2.5 are only relatively high in the northern region, while PM10 has a high background concentration in some areas of the north and south. It may be that the traffic volume in the northern region is large, which has a greater impact on the background mass concentration. At the same time, the large traffic volume raises more particles, which contributes more to the background mass concentration. The southern region may be affected by large trucks. The passage of large vehicles will bring up coarse particles in road dust, causing the PM10 background mass concentration to be higher during monitoring.

[0081] Step 2: Particle size spectrum and concentration analysis of particles raised by wheels

[0082] Figure 6 The results show that the wheel-lifted mass concentrations of PM1, PM2.5, and PM10 road dust in the monitoring period are significantly different. The spatial distribution of the wheel-lifted mass concentrations of PM1, PM2.5, and PM10 road dust in winter is similar, with higher mass concentrations in the northern and southern regions and relatively lower mass concentrations in the central region. This may be because there is less traffic on the roads in the central region during the monitoring period, or the time after the road cleaning is short. These factors will affect the mass concentrations of different particles during monitoring. The wheel-lifted mass concentration of PM1 road dust in summer is relatively large in the northern region, indicating that the content of fine particles in the northern region is relatively high in summer. The distribution of the wheel-lifted mass concentrations of PM2.5 and PM10 road dust is similar, with small areas of high concentrations. It may be that the construction sites around the road have a greater impact on their mass concentrations.

[0083] Step 3: Particle size spectrum and concentration analysis of road dust particles

[0084] The spatial characteristics of the mass concentrations of PM1, PM2.5, and PM10 of road dust during the monitoring period were analyzed, and the results were as follows: Figure 7As shown. The results show that the mass concentrations of PM1, PM2.5, and PM10 in road dust have completely different spatial distributions in summer and winter. But in general, the mass concentration distributions of PM1, PM2.5, and PM10 in road dust in summer are relatively consistent. Similarly, the mass concentration change characteristics of PM1, PM2.5, and PM10 in road dust in winter are also relatively consistent. Due to the frequent construction at construction sites in summer, there are different high-concentration areas compared to winter. The cold climate in winter is not conducive to construction work, resulting in high-concentration areas only appearing in the north and south of Tongzhou. The north is an area with relatively large traffic volume, and the south may be an area with more large trucks. These reasons lead to similar spatial distribution characteristics of the mass concentrations of PM1, PM2.5, and PM10 in road dust. In addition, road cleaning operations during the monitoring period will have a greater impact on the monitored mass concentrations.

[0085] Step 4: Analysis of particle size spectrum and concentration of dust particles on different types of roads and in different seasons

[0086] As shown in Table 1, the cumulative mass percentages of the five types of roads below 1μm, below 2.5μm and below 10μm are significantly different. The proportion of PM1 is relatively low, with national roads and provincial roads accounting for about 26% and 20% respectively. The difference for other types of roads is not much, basically around 15%. PM2.5 is relatively high, accounting for about 45%. PM10 accounts for the highest proportion, reaching about 100%, indicating that the particulate matter in road dust mainly exists in the form of larger coarse particles.

[0087] Table 1 Cumulative percentage of particle size mass of different grades of roads (%)

[0088]

[0089] Depend on Figure 8 It can be seen that the cumulative percentage of mass at 10μm for roads of different grades in summer and winter almost reaches 100%. In summer, the cumulative percentage of mass of national highways between 3.0μm and 7.5μm is different from that of other roads, and is smaller than other roads overall. In winter, the cumulative percentage of mass of national highways and provincial highways between 0.25μm and 2.0μm is greater than that of other roads, but it is smaller than other roads between 3.0μm and 7.5μm. In general, except for national highways and provincial highways, the cumulative percentage of mass of other roads in summer and winter is not much different. The roads with the highest and lowest proportions of <2.5μm in summer are village roads (50%) and provincial roads (40%). In winter, the opposite result is obtained, with the cumulative proportions of <2.5μm for provincial roads and village roads being about 46% and 41%, respectively.

[0090] The cumulative percentage of number concentration on roads of different grades has significantly different changing trends in summer and winter, such as Figure 8As shown in the figure, the cumulative percentage of number concentration of national roads is greater than that of other grades of roads in both summer and winter, reaching 99% at 1μm and 0.5μm respectively. In summer, the cumulative percentage of number concentration of provincial roads is generally smaller than other roads between 0.25μm and 7.5μm, and second only to national roads in winter. In winter, the cumulative percentage of number concentration of village roads reaches the minimum value in the entire particle size segment. The quality cumulative percentages of county roads and township roads are basically the same, only greater than village roads. In summer, the overall cumulative percentage of quality of county roads and village roads is not much different, and the curves are basically consistent. Overall, even if the road grades are different, the cumulative percentage of number concentration basically reaches 100% at 3μm in both summer and winter, indicating that the number concentration reaches a peak at 3μm.

[0091] Fig. 9 The mass proportion of roads of different grades in summer and winter, from which it can be concluded that there are two peaks in the mass proportion of roads of different grades in summer and winter, but the particle size when the peak appears is not the same. In winter, the first peak appears when the particle size is 2.5μm, and national roads and provincial roads account for about 20% of the total mass, and county roads, township roads, and village roads account for about 25%. When the particle size is greater than 5μm, the second peak appears at 8.5μm for national roads, provincial roads, county roads, township roads, and village roads, respectively, and their mass proportions are 17.9%, 9.1%, 8.8%, 6.8%, and 7.4%, respectively. The peaks of roads of different grades in winter appear in a basic comparison rule, but not in summer. In summer, the first peak of national roads, county roads, and village roads appears at 3.5μm, while the peaks of provincial roads and township roads appear at 4μm and 3μm, respectively, with little difference overall. For the second peak, except for the county road, which appears at 7.5μm, the others appear at 8.5μm, just like in winter. In winter, the proportion of the first peak is greater than that of the second peak, but there are special circumstances in summer. For national and provincial highways, the second peak is greater than the first.

[0092] Step 5: Analysis of potential spatial distribution characteristics of road dust diameter spectrum

[0093] The monthly variation characteristics of the emission potential of road dust particle size spectrum show that the month with the lowest emission potential of road dust particle size spectrum occurs in September (0.51 g / m 2 The highest value of dust particle size spectrum emission potential is in August, which is 1.12g / m 2 The emission potential of road dust particle size spectrum in April, October and December remained stable at 0.60g / m 2About. The main factors that affect the emission potential of road dust particle size spectrum include road conditions, construction conditions and bare soil conditions around the road, road cleaning frequency, weather factors, etc. Therefore, the monitoring values ​​of road dust particle size spectrum emission potential in different months are very different. It is highest in summer. It may be because there is more rain in summer, and road dust mixes with rainwater to form "mud water", which is brought to the motor vehicle lane by pedestrians or motor vehicles, causing the emission potential of dust particle size spectrum to be high. The wind speed in autumn is relatively low, which is not conducive to the road dust being lifted up by human activities and vehicles, which will make the emission potential of dust particle size spectrum relatively low. In addition, the emission potential of dust particle size spectrum in February and May is relatively large, which are 0.93g / m 2 , 0.95g / m 2 It may be caused by the construction site next to the road and the spillage of muck trucks on the road.

[0094] Based on the vehicle-mounted mobile monitoring system, the present invention samples and monitors the emission potential of dust particle size spectrum of nearly 150 roads, and can obtain high-resolution data of longitude and latitude and corresponding road dust particle size spectrum emission potential. The processing tool of ArcGIS software is used to visualize the emission potential of road dust particle size spectrum in each season. The test results are shown in Fig.10 It can be seen that the spatial variation characteristics of the road dust particle size spectrum emission potential in the four seasons are not obvious. Overall, the road dust particle size spectrum emission potential is the smallest in autumn, with an average value of 0.61g / m 2 The emission potential of road dust particle size spectrum in summer is the highest, with an average value of 0.83g / m 2 The emission potential of road dust particle size spectrum in spring and winter is not much different, with an average value of 0.75g / m 2 This result shows that in the four seasons, the temperature is lower in winter, and it is not easy to generate dust on the road, which may make the emission potential of road dust particle size spectrum smaller than that in other seasons. In winter, the emission potential of road dust particle size spectrum is lower because the road dust accumulation can be controlled by increasing the cleaning efforts. It can be seen that increasing road mechanization can effectively control road dust accumulation. In summer, there is more rain, which brings more muddy water, which increases the emission potential of road dust particle size spectrum.

[0095] Step 6: Emission factor analysis of road dust particle size spectrum

[0096] The road dust emission factors of different particle size ranges of each grade of roads obtained by the present invention are shown in Table 2. The emission factors of road dust PM2.5, PM10, and TSP are in the order of provincial roads > county roads > national roads > village roads > township roads. Among them, the emission factors of PM2.5 are (0.56±0.36), (0.52±0.43), (0.48±0.32), (0.32±0.26), and (0.32±0.47), respectively. Although the emission potential of the dust particle size spectrum of the national highway is the smallest, the average vehicle weight is the largest, so the road dust emission factor of the national highway is in the middle. The emission potential and average vehicle weight of the dust particle size spectrum of the county road are in the middle, but the particle size multiplier is large, so the road dust emission factor of the county road is relatively large. Since the average vehicle weight of township roads and village roads is quite different from that of other grades of roads, the road dust emission factor is also small.

[0097] Table 2 Road dust emission factors for different particle size ranges on various grades of roads

[0098]

[0099] ArcGIS software was used to grid the emission factors and obtain the spatial distribution characteristics of road dust emission factors in different particle size ranges, such as Fig.11 As shown. The results show that the road dust emission factor has a certain relationship with the road network density and the type of vehicles on the road. In some areas near the main urban area, the road network is dense, and the road dust PM2.5, PM10, and TSP emission factors are also relatively large. Although the road dust particle size spectrum emission potential in some areas near the main urban area is not high, the road network is dense, the traffic volume is large, and the vehicle weight is correspondingly large, so this part of the area is higher than other areas. It can be seen that parameters such as particle size multiplier, road dust particle size spectrum emission potential, and average vehicle weight will have a greater impact on the emission factor.

[0100] Step 7: Emission intensity analysis of road dust particle size spectrum

[0101] The emission intensity of road dust in different particle size ranges of each grade of roads is shown in Table 3. The order of size is national highway > provincial highway > county highway > township road > village road, which is consistent with the order of traffic volume of different grades of roads, indicating that the emission intensity of road dust is mainly affected by the traffic volume. The emission intensity of road dust PM2.5 of national highway, provincial highway, county highway, township road and village road is about 16.2, 8.1, 3.5, 0.5 and 0.2 kg·(km·d)-1, and the emission intensity of different grades of roads varies greatly.

[0102] Table 3 Road dust emission intensity in different particle size ranges for each grade of road

[0103]

[0104] The road dust emission intensity of each particle size range of different grades of roads was obtained based on ArcGIS, and the spatial distribution map was made using analysis tools. Fig.12 It can be seen that the emission intensity of the area close to the main urban area is relatively high, mainly because the daily traffic volume is relatively large and the road network is relatively dense. The traffic volume has the greatest impact on the emission intensity, and the impact of other parameters is relatively small, because the roads with large traffic volume can differ from those with small traffic volume by several orders of magnitude, and the size of other parameters is basically small. Therefore, different road types will have a greater impact on PM2.5, PM10, and TSP emission intensity.

[0105] Step 8: Spatial distribution analysis of road dust particle size spectrum

[0106] According to the survey, the traffic volume and vehicle type distribution information, road network information (road name, type, length) were obtained, and the emission factor was calculated using the AP model and the monitored dust particle size spectrum emission potential. The emission amount was calculated, and ArcGIS software was used to establish a bottom-up road dust emission inventory of 500m×500m. The PM2.5, PM10 and TSP emissions of national roads, provincial roads, county roads, township roads and village roads were statistically analyzed, as shown in Table 4. The PM2.5, PM10 and TSP emissions were 2271, 7673 and 39975t / a, respectively. Among them, the road type with the largest road dust emissions is the national road, with PM2.5, PM10 and TSP emissions of 977, 3143 and 16373t / a, respectively.

[0107] Table 4 Road dust emissions in different particle size ranges for each grade of road

[0108]

[0109] ArcGIS was used to count the road dust emissions in different particle size ranges, and its spatial distribution is shown in Fig.13 , it can be seen that the spatial distribution of PM2.5, PM10 and TSP in road dust is similar. The maximum grid emissions of PM2.5, PM10 and TSP all appear in urban areas. Although the emission potential of urban road dust particle size spectrum is small, the traffic volume is large, so the emission is high. Moreover, the emissions near the main urban area are relatively high. The results show that the distribution of road dust emissions is highly correlated with the road network density, and the traffic volume is the main factor affecting road dust emissions.

[0110] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A cruise monitoring device for road dust particle size spectrum emission potential, comprising: Particle collection unit, vacuum pump, particle size spectrum monitoring unit, vehicle positioning system, auxiliary unit, power supply unit and data collection and transmission unit, including: The particle collection unit includes two sampling pipelines. The dust sampling port of one sampling pipeline is located behind the front right tire to collect the road particles suspended by the rotating tire during the driving of the motor vehicle. The background point sampling port of the other sampling pipeline is located on the top of the experimental vehicle to detect the particle samples in the ambient background air for comparison with the road particles collected by the dust sampling port. A vacuum pump, which provides power for the sampling head and collects dust particles in the sampling pipeline. The vacuum pump is equipped with a motor or is independent without a motor; The particle size spectrum monitoring unit includes a particle size spectrum monitor 1 and a particle size spectrum monitor 2, which are used to detect the particle size spectrum concentration of the particles in the air; The vehicle positioning system is used to locate the vehicle; The auxiliary unit is used to provide meteorological parameters of weather; The data acquisition and transmission unit is used for data acquisition and transmission; The power supply unit includes a power supply and a single-phase high-pressure fan, which provide power for the entire detection system and adjust the sampling flow in the sampling pipeline through a flow controller and a flow probe in the sampling pipeline, thereby controlling the gas velocity at the sampling inlet and minimizing the impact of non-constant speed sampling on particulate matter.

2. A road dust vehicle-mounted mobile monitoring system for real-time monitoring of road dust particle size distribution, measurement of road area dust particle size spectrum emission potential, and sampling of road traffic dust particle size spectrum, including: Two sampling pipelines, one end of one sampling pipeline (4) is a sampling port, and the sampling pipeline (4) is provided with a vacuum pump, a flow rate measuring device composed of a flow controller (2) and a flow probe (3), a particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer (5), and a gas conveying device composed of a fan (1) in sequence along the gas flow direction; the other pipeline is connected to the particle size spectrum concentration measuring device composed of an EDM180 particle size spectrometer (7) for detecting the particle size spectrum concentration in the background air; A data acquisition, transmission and processing system 11 and a global positioning system GPS device (8), wherein the GPS system (8) is connected to the data acquisition, transmission and processing system (11); the flow velocity measuring device, the particle size spectrum concentration measuring device, and the gas delivery device are all connected to the data acquisition, transmission and processing system (11); and the generator (12) provides power for the fan (1).

3. The road dust vehicle-mounted mobile monitoring system according to claim 2 is characterized in that: A sampling cup is arranged on the gas circulation pipeline of the particle size spectrum concentration measuring device. The sampling cup is hollow, and the inner diameter of one end is larger than the inner diameter of the other end. By placing different sampling cups, the gas flow rate of the gas circulation pipeline can be adjusted.

4. The road dust vehicle-mounted mobile monitoring system according to claim 2 is characterized in that: The EDM1 80 particle size spectrometer adopts the principle of laser scattering and can simultaneously obtain the mass concentration values ​​of PM10, PM2.5, PM1 in the real road traffic environment and the road dust raised by the wheels, and the particle number concentration of 31 particle size segments in the range of 0.25 to 32 μm.

5. A vehicle-mounted mobile monitoring and tracing method using the vehicle-mounted mobile monitoring system for road dust according to any one of claims 2 to 4, wherein the road dust particle size spectrum emission potential is a function of dust concentration and vehicle operating status, and the vehicle-mounted mobile monitoring method performs numerical and particle size distribution characteristic analysis of the road dust particle size spectrum emission potential according to the function, wherein: The conversion formula for the emission potential of road dust particle size spectrum based on the concentration value of multi-size particles is shown in formula (1). The road dust vehicle-mounted mobile monitoring system measures T and s in real time, where T is the concentration at the sampling point minus the background point concentration. The frequency of real-time measurement and recording of data is in seconds or sub-seconds. sL=a·d·e·T b ·s -c (1) Where: sL ------- road dust particle size spectrum emission potential, g / m 2 ; a-------Constant coefficient, the default value is 1.00, or it can be obtained by fitting measured data with multiple regression method; d------Season coefficient, the default is 0.98 for spring, 1.03 for summer, 1.07 for autumn, and 1.18 for winter; e--------Particle size coefficient, when the monitored particulate matter is PM2.5, it is 1; when the monitored particulate matter is PM10, it is 0.50 for urban roads, national roads and provincial roads, and 0.47 for county roads and township roads; T-------Difference in particle concentration between sampling point and background point, mg / m3; b-------concentration coefficient, the default recommended value is 0.7752, and it can also be determined by the power exponent of the power exponential function relationship between concentration and emission potential obtained through experiments; s-------Driving speed of the cruise monitoring vehicle, km / h; c-------vehicle speed coefficient, the default recommended value is 1.8613, and it can also be determined by obtaining the power exponent of the power exponential function relationship between concentration and vehicle speed through experiments; Formula (1) is used for the following analysis: Step 1: Background particle size spectrum concentration distribution analysis; Step 2: particle size spectrum and concentration analysis of particles raised by wheels; Step 3: Particle size spectrum concentration analysis of road dust particles; Step 4: Analysis of particle size spectrum concentration of dust particles on different types of roads and in different seasons; Step 5: Analyze the potential spatial distribution characteristics of road dust diameter spectrum; Step 6: Emission factor analysis of road dust particle size spectrum; Step 7: Emission intensity analysis of road dust particle size spectrum; Step 8: Analyze the spatial distribution of road dust particle size spectrum emissions.

6. The vehicle-mounted mobile monitoring and tracing method according to claim 5 is characterized in that: The step 1 uses the spatial interpolation method of ordinary Kriging to obtain the spatial variation trend of the background mass concentrations of road dust PM1, PM2.5, and PM10 during the monitoring period.

7. The vehicle-mounted mobile monitoring and tracing method according to claim 5 is characterized in that: The step 2 analyzes and obtains the spatial variation pattern of the wheel-raised mass concentrations of road dust PM1, PM2.5, and PM10 during the monitoring period.

8. The vehicle-mounted mobile monitoring and tracing method according to claim 5 is characterized in that: The step 3 analyzes the spatial characteristics of the mass concentrations of PM1, PM2.5 and PM10 of road dust during the monitoring period.

9. The vehicle-mounted mobile monitoring and tracing method according to claim 5 is characterized in that: The step 5 uses the processing tools of ArcGIS software to visualize the emission potential of road dust particle size spectrum in each season.

10. The vehicle-mounted mobile monitoring and tracing method according to claim 5, characterized in that: In step 8, based on the traffic volume, vehicle type distribution information, and road network information, the emission factor is calculated using the model and the emission potential of the dust particle size spectrum obtained through monitoring, and ArcGIS software is used to calculate the emission amount, and a bottom-up 500m×500m road dust emission inventory is established; the PM2.5, PM10, and TSP emissions of national roads, provincial roads, county roads, township roads, and village roads are counted.

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