Region classification method based on floating population and environmental exposure change

Abstract

The invention belongs to the technical field of area classification, and particularly relates to an area classification method based on floating population and environmental exposure change, and the method comprises the following steps: S1, data collection: collecting three types of data: the first type is floating population individual data; the second type is pollution concentration annual average data, the pollution concentration annual average data is lattice point data, and the spatial resolution is 1 kilometer * 1 kilometer; the third type is population number grid point data, the spatial resolution is 1 kilometer * 1 kilometer, and the time resolution is year by year; s2, data preprocessing: according to administrative boundaries of each district and county in China, pollution concentration annual average data and population number grid point data are cut, and then a population weighted average pollution concentration value of each district and county is calculated; s3, calculating an average pollution exposure change under a given migration path; and S4, dividing provinces according to the migration path population proportion and pollution exposure change.

Description

Technical Field

[0001] The present invention belongs to the technical field of regional classification, and particularly relates to a regional classification method based on changes in floating population and environmental exposure. Background Art

[0002] The scale of the floating population in China is huge, and it is of great social and livelihood significance to pay attention to its atmospheric environmental exposure. At present, there are many technologies for analyzing the migration space pattern of the floating population. Most of these technologies classify different provinces based on the indicators of immigration and emigration intensity. However, in the analysis of the migration space pattern, the existing technologies lack the analysis perspective of the change in the environmental exposure of the floating population. The change in pollution exposure during the migration process of the floating population is closely related to the place of origin and the place of destination of the floating population. How to incorporate the characteristics of pollution exposure change into the migration space pattern classification is an important content of the present invention. When proposing the method of the present invention, there are the following technical problems:

[0003] (1) Given the province of origin, based on the individual data of the floating population, how to calculate the average pollution exposure change of the floating population during the migration process. In the process of solving this technical problem, it is necessary to consider the number of floating population on different migration paths and the corresponding pollution exposure changes as a whole.

[0004] (2) Given the proportions of different migration paths and the corresponding average pollution exposure changes, how to divide the provinces of origin.

[0005] (3) Given the average pollution exposure changes of intra-provincial migration and inter-provincial migration, how to divide the provinces of origin. Summary of the Invention

[0006] The purpose of the present invention is to propose a regional classification method based on the floating population and environmental exposure changes in view of the lack of a migration space pattern classification method based on the environmental exposure changes of the floating population, and the existing technologies usually only consider the immigration and emigration intensity of the population.

[0007] In order to achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions:

[0008] A regional classification method based on the floating population and environmental exposure changes, comprising the following steps:

[0009] S1. Data collection: Collect three types of data. Among them, the first type is the individual data of the floating population; for each individual data of the floating population, it includes the information of the current place of residence and the place of household registration, and both the current place of residence and the place of household registration are detailed to the district and county level;

[0010] The second category is the annual average pollution concentration data, which is grid data with a spatial resolution of 1 km × 1 km. The third category is the population grid data with a spatial resolution of 1 km × 1 km and a temporal resolution of yearly.

[0011] S2. Data preprocessing: According to the administrative boundaries of each district and county in China, the annual average pollution concentration data and population grid data are cut, and then the population-weighted average pollution concentration value of each district and county is calculated. The calculation formula is as follows:

[0012]

[0013] In formula (1), APC i is the population-weighted average pollution concentration of county i in a certain year, j represents the jth 1 km × 1 km grid point in the county, POP j and APC j are the population size and annual average pollution concentration of the grid point respectively;

[0014] S3. Calculate the average pollution exposure change under a given migration path;

[0015] S4. Divide provinces according to population proportion along migration paths and changes in pollution exposure.

[0016] Further as a preferred technical solution of the present invention, S3 comprises the following steps:

[0017] S301: Calculate the change in pollution exposure of individual migrants: For each individual migrant, calculate the difference in pollution concentration between the registered residence and the current residence. The pollution concentration adopts the population-weighted average pollution concentration value of formula (1);

[0018] S302: Screening migration paths: Given a province, screen all migrant individuals whose registered residence is in the province, and then classify the migrant population into two categories: intra-provincial migration and inter-provincial migration, depending on whether the current residence of these migrants is still in the province;

[0019] S303: Calculate the average pollution exposure change under a given migration path: Given a province, screen all the individuals of the migrant population within the province, and calculate the average pollution exposure change of the migration within the province based on the pollution exposure change of each individual. The calculation formula is as follows:

[0020]

[0021] In formula (2), ΔAPC s，sn is the average pollution exposure change of intra-provincial migrants sn in a province s, N s，sn is the number of migrant population in the province, Count kFor the number of floating population with pollution exposure changes in the interval bin k , where bin k is set as follows:

[0022] bin 1 = [-60, -59)

[0023] bin 2 = [-59, -58)

[0024] bin 3 = [-58, -57)

[0025] ……

[0026] bin l = [59, 60)

[0027] ΔAPC k is the average pollution exposure change in the interval bin k ;

[0028] Similar to calculating the average pollution exposure change of intra-provincial migration, the following formula is used to calculate the average pollution exposure change of inter-provincial migration:

[0029]

[0030] In formula (3), N s，sw is the number of floating population of inter-provincial migration.

[0031] Furthermore, as a preferred technical solution of the present invention, S4 includes the following steps:

[0032] S401: Calculate the proportion of intra-provincial migration population and the proportion of inter-provincial population: Given a province, screen all individual floating population with household registration in that province, and then calculate the ratio ratio s，sn of the intra-provincial migration population to all floating population, and calculate the ratio ratio s，sw of the inter-provincial migration population to all floating population;

[0033] S402: Divide the given province according to the above proportions and the corresponding pollution exposure changes;

[0034] S403: Divide the province according to the pollution exposure change; If the proportion of intra-provincial migration population and the proportion of inter-provincial migration population are not considered, divide the province only according to the average pollution exposure changes of the two different migration paths.

[0035] Furthermore, as a preferred technical solution of the present invention, the division criteria and the corresponding meanings in S402 are: When the migration population ratio ratio s，sn > 50%, the pollution exposure change ΔAPCs，sn > 0, Category name: Internal flow pollution exposure deterioration type, corresponding meaning: The floating population mainly migrates within the province, and the floating population of this type mainly flows to areas with severe pollution; When the proportion of migrant population ratio s，sn > 50%, Pollution exposure change ΔAPC s，sn < 0, Category name: Internal flow pollution exposure reduction type, corresponding meaning: The floating population mainly migrates within the province, and the floating population of this type mainly flows to areas with less pollution; When the proportion of migrant population ratio s，sw > 50%, Pollution exposure change ΔAPC s，sw > 0, Category name: Cross - regional flow pollution exposure deterioration type, corresponding meaning: The floating population mainly migrates across provinces, and the floating population of this type mainly flows to areas with severe pollution;

[0036] When the proportion of migrant population ratio s，sw > 50%, Pollution exposure change ΔAPC s，sw < 0, Category name: Cross - regional flow pollution exposure reduction type, corresponding meaning: The floating population mainly migrates across provinces, and the floating population of this type mainly flows to areas with less pollution;

[0037] When the proportion of migrant population ratio s，sn ≈ ratio s，sw , Pollution exposure change ΔAPC s > 0, Category name: Balanced flow pollution exposure deterioration type, corresponding meaning: The in - province migration is equivalent to the cross - province migration, and all the floating population mainly flows to areas with severe pollution;

[0038] When the proportion of migrant population ratio s，sn ≈ ratio s，sw , Pollution exposure change ΔAPC s < 0, Category name: Balanced flow pollution exposure reduction type, corresponding meaning: The in - province migration is equivalent to the cross - province migration, and all the floating population mainly flows to areas with less pollution.

[0039] Furthermore, as a preferred technical solution of the present invention, the classification criteria and corresponding meanings in S403 are: When the pollution exposure change of in - province migration ΔAPC s，sn < 0, and the pollution exposure change of cross - province migration ΔAPC s，sw < 0, Category name: Bilateral pollution exposure reduction type, corresponding meaning: The pollution exposure of the floating population is reduced both during in - province migration and cross - province migration;

[0040] When the pollution exposure change of in - province migration ΔAPC s，sn > 0, and the pollution exposure change of cross - province migration ΔAPC s，sw> 0, Category name: Bilateral Pollution Exposure Deterioration Type, corresponding meaning: The pollution exposure deteriorates both during the intra-provincial migration and inter-provincial migration of the floating population;

[0041] When the change in pollution exposure during intra-provincial migration ΔAPC s，sn > 0, the change in pollution exposure during inter-provincial migration ΔAPC s，sw < 0, Category name: Internal Deterioration and External Mitigation Type, corresponding meaning: The pollution exposure of the floating population deteriorates during intra-provincial migration, but mitigates during inter-provincial migration;

[0042] When the change in pollution exposure during intra-provincial migration ΔAPC s，sn < 0, the change in pollution exposure during inter-provincial migration ΔAPC s，sw > 0, Category name: Internal Mitigation and External Deterioration Type, corresponding meaning: The pollution exposure of the floating population mitigates during intra-provincial migration, but deteriorates during inter-provincial migration.

[0043] A regional classification method based on the floating population and environmental exposure changes according to the present invention, compared with the prior art by adopting the above technical solution, has the following technical effects:

[0044] The prior art mainly analyzes the air pollution exposure level from the perspective of the permanent population, and divides different regions based on this, ignoring the mobility during the population migration and the pollution exposure changes of the floating population during the migration process. Considering that the proportion of the floating population in China's total population has approached 30%, therefore, by comprehensively considering the migration trajectory and pollution exposure changes to divide different regions, it can provide a scientific basis for improving and enhancing the environmental health of the floating population. Brief Description of the Drawings

[0045] Figure 1 It is a schematic flow chart of the method of the embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of the average pollution exposure changes of PM2.5 corresponding to intra-provincial migration and inter-provincial migration of each province in the embodiment of the present invention. Detailed Embodiment

[0047] The following will be described in detail with reference to the drawings to further explain the present invention, so that those skilled in the art can understand the present invention more deeply and be able to implement it. However, the following is only used to explain the present invention by referring to examples and does not limit the present invention.

[0048] As Figure 1 shown, a regional classification method based on the floating population and environmental exposure changes includes the following steps:

[0049] S1. Data collection: Three types of data are collected, among which the first type is individual data of migrant population; this data comes from the 2017 China Migrant Population Dynamic Monitoring Survey Dataset. The data sample includes nearly 170,000 migrant population individuals, which is representative of the whole country and each province. For each individual data of migrant population, it includes information on current residence and registered permanent residence, and the current residence and registered permanent residence are detailed to the district and county level;

[0050] The second category is the annual average pollution concentration data, which is grid data with a spatial resolution of 1 km × 1 km. The third category is the population grid data with a spatial resolution of 1 km × 1 km and a temporal resolution of yearly.

[0051] S2. Data preprocessing: Since the floating population survey data are from 2017, the pollution concentration and population grid data sets also use the 2017 data sets. According to the administrative boundaries of each district and county in China, the annual average pollution concentration data and population grid data are trimmed, and then the population-weighted average pollution concentration value of each district and county is calculated. The calculation formula is as follows:

[0052]

[0053] In formula (1), APC i is the population-weighted average pollution concentration of county i in 2017, j represents the jth 1 km × 1 km grid point in the county, POP j and APC j are the population size and annual average pollution concentration of the grid point respectively;

[0054] S3. Calculate the average pollution exposure change under a given migration path;

[0055] S4. Divide provinces according to the proportion of population along migration paths and changes in pollution exposure.

[0056] S3 includes the following steps:

[0057] S301: Calculate the change in pollution exposure of individual migrants: For each individual migrant, calculate the difference in pollution concentration between the registered residence and the current residence. The pollution concentration adopts the population-weighted average pollution concentration value of formula (1);

[0058] S302: Screening migration paths: Given a province, screen all migrant individuals whose registered residence is in the province, and then classify the migrant population into two categories: intra-provincial migration and inter-provincial migration, depending on whether the current residence of these migrants is still in the province;

[0059] S303: Calculate the average change in pollution exposure along a given migration path: Given a province, filter all individual migrants within the province, and calculate the average change in pollution exposure for intra-provincial migration based on the change in pollution exposure of each individual. The calculation formula is as follows:

[0060]

[0061] In formula (2), ΔAPC s，sn is the average change in pollution exposure for intra-provincial migration sn in a certain province s, and N s，sn is the number of intra-provincial migrant population, and Count k is the number of the migrant population within the interval bin k for the change in pollution exposure, where bin k is set as follows:

[0062] bin 1 = [-60, -59)

[0063] bin 2 = [-59, -58)

[0064] bin 3 = [-58, -57)

[0065] ……

[0066] bin l = [59, 60)

[0067] ΔAPC k is the average change in pollution exposure within the interval bin k ;

[0068] Similar to the calculation of the average change in pollution exposure for intra-provincial migration, the following formula is used to calculate the average change in pollution exposure for inter-provincial migration:

[0069]

[0070] In formula (3), N s，sw is the number of inter-provincial migrant population.

[0071] S4 includes the following steps:

[0072] S401: Calculate the proportion of intra-provincial migrants and the proportion of inter-provincial migrants: Given a province, filter all individual migrants whose household registration is in this province, and then calculate the ratio ratio s，sn of intra-provincial migrants to all migrants, and calculate the ratio ratio s，sw of inter-provincial migrants to all migrants;

[0073] S402: Divide a given province according to the above ratios and corresponding changes in pollution exposure;

[0074] Divide provinces according to the proportion of migrant population and changes in pollution exposure, as shown in Table 1:

[0075] Table 1

[0076]

[0077] S403: Divide provinces according to changes in pollution exposure; if the proportion of intra-provincial migrant population and the proportion of inter-provincial migrant population are not considered, divide provinces only according to the average change in pollution exposure of two different migration paths;

[0078] Divide provinces according to changes in pollution exposure, as shown in Table 2:

[0079] Table 2

[0080]

[0081]

[0082] In specific implementation, the embodiment takes PM2.5 pollution exposure as an example and is based on the 2017 China Migrants Dynamic Survey dataset.

[0083] PM2.5 pollution concentration grid data comes from the CHAP public dataset (https: / / zenodo.org / records / 6398971), and population quantity grid data comes from the WorldPop dataset (https: / / www.worldpop.org / ). The spatial resolution of these two grid data is both 1 km × 1 km. Divide different provinces in China according to these data.

[0084] Calculate the average change in pollution exposure under a given migration path: Calculate the change in PM2.5 pollution exposure of all floating population individuals one by one. According to the gridded PM2.5 concentration and population quantity data, calculate the population-weighted average PM2.5 concentration of each district and county in China in 2017. On this basis, calculate the change in PM2.5 pollution exposure of each floating individual according to the household registration location and current residence of each floating individual.

[0085] Screen intra-provincial migration and inter-provincial migration paths. Given a province, select all floating population whose household registration location is in this province, and then determine whether the floating individual is an intra-provincial migrant or an inter-provincial migrant according to whether the current residence is within this province.

[0086] Calculate the changes in average PM2.5 pollution exposure corresponding to intra-provincial migration and inter-provincial migration. For a given province, based on the determination of the floating population for intra-provincial migration and migration outside the province, combined with the changes in PM2.5 pollution exposure of each floating individual, using formula (1) and formula (2), calculate the changes in average PM2.5 pollution exposure for intra-provincial migration and the changes in average PM2.5 pollution exposure for inter-provincial migration respectively.

[0087] Divide the provinces according to the population proportion of the migration path and the pollution exposure changes:

[0088] For each province, calculate the proportion of the intra-provincial migrant population and the proportion of the inter-provincial migrant population. Combined with the changes in average PM2.5 pollution exposure, divide multiple provinces. The division results are shown in Table 3:

[0089] Table 3 Division results of provinces according to the proportion of migrant population and pollution exposure changes

[0090]

[0091]

[0092] (Note: The China Floating Population Dynamic Monitoring Survey dataset lacks data in some provinces or municipalities directly under the Central Government. Therefore, some provinces and cities are not listed here)

[0093] Divide the provinces according to the pollution exposure changes: Calculate the changes in average PM2.5 pollution exposure for intra-provincial migration and the changes in average PM2.5 pollution exposure for inter-provincial migration of each province. These pollution exposure changes are as Figure 2 shown;

[0094] Based on the above results, divide each province. The division results are shown in Table 4:

[0095] Table 4 Division results of provinces according to pollution exposure changes

[0096]

[0097] Using the method provided by the present invention, the layout of PM 2.5 observation stations in the city can be quantitatively evaluated. During the evaluation process, the coverage range and population of the stations, as well as the redundancy between the stations, are comprehensively considered.

[0098] The above-mentioned specific implementation plans further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above is only the specific implementation plans of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A regional classification method based on changes in floating population and environmental exposure, characterized in that: The following steps are involved: S1. Data collection: Three types of data are collected, of which the first type is individual data of migrant population; for each individual data of migrant population, it includes information on current residence and registered permanent residence, and both the current residence and registered permanent residence are detailed to the district and county level; The second category is the annual average pollution concentration data, which is grid data with a spatial resolution of 1 km × 1 km; The third category is population grid data, with a spatial resolution of 1 km × 1 km and a temporal resolution of yearly; S2. Data preprocessing: According to the administrative boundaries of each district and county in China, the annual average pollution concentration data and population grid data are cut, and then the population-weighted average pollution concentration value of each district and county is calculated. The calculation formula is as follows: In formula (1), APC i is the population-weighted average pollution concentration of county i in a certain year, j represents the jth 1 km × 1 km grid point in the county, POP j and APC j are the population size and annual average pollution concentration of the grid point respectively; S3. Calculate the average pollution exposure change under a given migration path; S4. Divide provinces according to the proportion of population along migration paths and changes in pollution exposure.

2. The regional classification method based on floating population and environmental exposure changes according to claim 1 is characterized in that: The S3 comprises the following steps: S301: Calculate the change in pollution exposure of individual migrants: For each individual migrant, calculate the difference in pollution concentration between the registered place of residence and the current place of residence. The pollution concentration adopts the population-weighted average pollution concentration value of formula (1); S302: Screening migration paths: Given a province, screen all migrant individuals whose registered residence is in the province, and then classify the migrant population into two categories: intra-provincial migration and inter-provincial migration, depending on whether the current residence of these migrants is still in the province; S303: Calculate the average pollution exposure change under a given migration path: Given a province, screen all the individuals of the migrant population within the province, and calculate the average pollution exposure change of the migration within the province based on the pollution exposure change of each individual. The calculation formula is as follows: In formula (2), ΔAPC s，sn is the average pollution exposure change of intra-provincial migrants sn in a province s, N s，sn is the number of migrant population in the province, Count k For pollution exposure changes in interval bin k The number of floating population in bin k The settings are as follows: bin1=[-60,-59) bin2=[-59,-58) bin3=[-58,-57) …… bin l =[59,60) ΔAPC k For the interval bin k changes in average pollution exposure within; Similar to the calculation of the average pollution exposure change for intra-provincial migration, the following formula is used to calculate the average pollution exposure change for inter-provincial migration: In formula (3), N s，sw It is the number of migrant population migrating across provinces.

3. The regional classification method based on floating population and environmental exposure changes according to claim 2 is characterized in that: The S4 comprises the following steps: S401: Calculate the ratio of intra-provincial migrant population and inter-provincial population: Given a province, filter all migrant individuals whose registered residence is in that province, and then calculate the ratio of intra-provincial migrant population to all migrant population. s，sn , and calculate the ratio of inter-provincial migrant population to all floating population s，sw ; S402: Divide a given province according to the above ratios and corresponding changes in pollution exposure; S403: Divide provinces based on changes in pollution exposure. If the proportion of migrants within a province and the proportion of migrants across provinces are not taken into account, the provinces are divided only based on the average changes in pollution exposure along the two different migration paths.

4. The regional classification method based on floating population and environmental exposure changes according to claim 3 is characterized in that: The classification criteria and corresponding meanings in S402 are: When the proportion of migrant population s，sn >50%, pollution exposure change ΔAPC s，sn >0, Category name: Internal mobile pollution exposure deterioration type, corresponding meaning: the floating population mainly migrates within the province, and this type of floating population mainly flows to areas with serious pollution; when the proportion of migrant population ratio s，sn >50%, pollution exposure change ΔAPC s，sn <0, category name: Internal mobile pollution exposure reduction type, corresponding meaning: the floating population mainly migrates within the province, and this type of floating population mainly flows to areas with less pollution; When the proportion of migrant population s，sw >50%, pollution exposure change ΔAPC s，sw >0, category name: cross-regional mobile pollution exposure aggravation type, corresponding meaning: the floating population mainly migrates across provinces, and this type of floating population mainly flows to areas with serious pollution; When the proportion of migrant population s，sw >50%, pollution exposure change ΔAPC s，sw <0, category name: cross-regional mobile pollution exposure reduction type, corresponding meaning: the floating population mainly migrates across provinces, and this type of floating population mainly flows to areas with less pollution; When the proportion of migrant population s，sn ≈ratio s，sw , pollution exposure change ΔAPC s >0, category name: Balanced mobility pollution exposure deterioration type, corresponding meaning: intra-provincial migration is equivalent to inter-provincial migration, and all migrant population mainly flows to areas with serious pollution; When the proportion of migrant population s，sn ≈ratio s，sw , pollution exposure change ΔAPC s <0, category name: Balanced mobility pollution exposure reduction type, corresponding meaning: intra-provincial migration is equivalent to inter-provincial migration, and all migrant population mainly flows to areas with less pollution.

5. The regional classification method based on floating population and environmental exposure changes according to claim 4 is characterized in that: The classification criteria and corresponding meanings in S403 are: When intra-provincial migration changes pollution exposure ΔAPC s，sn <0, cross-provincial migration pollution exposure change ΔAPC s，sw <0, category name: bilateral pollution exposure reduction type, corresponding meaning: the pollution exposure of floating population is reduced during migration within the province and across provinces; When intra-provincial migration changes pollution exposure ΔAPC s，sn > 0, cross-provincial migration pollution exposure change ΔAPC s，sw >0, category name: bilateral pollution exposure deterioration type, corresponding meaning: the pollution exposure of migrant population deteriorates during migration within the province and across provinces; When intra-provincial migration changes pollution exposure ΔAPC s，sw > 0, cross-provincial migration pollution exposure change ΔAPC s，sw <0, category name: internal deterioration and external mitigation type, corresponding to the following meaning: the pollution exposure of floating population deteriorates during migration within the province, but is reduced during migration across provinces; When intra-provincial migration changes pollution exposure ΔAPC s，sn <0, cross-provincial migration pollution exposure change ΔAPC s，sw >0, category name: internal reduction and external deterioration type, corresponding meaning is: the pollution exposure of migrant population is reduced during migration within the province, but the pollution exposure is deteriorated during cross-provincial migration.

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