Methods for analyzing the origin of black carbon

Abstract

The present invention relates to environmental monitoring, and in particular to a method for analyzing the source of black carbon, comprising the following steps: Step 1, collecting data in n cycles, and in each cycle, the absorption coefficient b ji and wavelength λ i Correspondingly, i=1,2…N, we get j The corresponding coefficient k j and the absorption index α j , j = 1, 2…n, α ff =(α j ) min , α bb =(α j ) max ; Step 2, based on the data collected in each cycle, coefficient k j , α ff and α bb , get the k corresponding to each cycle jff ; Step 3, obtain each cycle T j The corresponding k jbb =k j ‑k jff ; Step 4, obtain each cycle T j The corresponding biomass contribution to black carbon concentration BC jbb,% , fossil fuels contribute to black carbon concentrations BC jff,% The present invention has the advantages of accurate analysis and the like, and is applied in the analysis of black carbon sources.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection, and in particular to a method for analyzing the source of black carbon. Background Art

[0002] The black carbon source analysis model assumes that black carbon (BC) comes from fossil fuel combustion and biomass combustion. By selecting the absorption coefficients of two wavelengths, near-infrared and near-ultraviolet, the contribution of biomass combustion to BC is calculated according to the following formula.

[0003] .

[0004] BC bb,% is the contribution of biomass combustion in BC, b abs (λ) is the absorption coefficient of wavelength λ, α bb is the absorption index of biomass combustion, α ff is the absorption index of fossil fuel combustion, MAC ff (λ) is the mass absorption cross section of fossil fuel combustion, MAC bb (λ) is the mass absorption cross section of biomass combustion. The black carbon source analysis model sets the fossil fuel combustion absorption index and the biomass combustion source absorption index to fixed values ​​of 1 and 2. ff (λ 2 ) / MAC bb (λ 2 ) is taken as 1, and the contribution ratio of biomass combustion can be obtained according to the above formula.

[0005] The accuracy of the above source analysis is poor. The main reasons are as follows:

[0006] 1. The black carbon source analysis model sets the absorption coefficient of fossil fuel combustion and the absorption coefficient of biomass combustion to an empirical value. In fact, the absorption coefficients of fossil fuel combustion and biomass combustion vary in different regions and at different times, which makes the analysis results very uncertain.

[0007] 2. The model only uses information from two wavelengths, and the analysis results will be affected by the wavelength selection. Summary of the invention

[0008] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a method for analyzing the source of black carbon.

[0009] The objective of the present invention is achieved through the following technical solutions:

[0010] A method for analyzing the source of black carbon comprises the following steps:

[0011] Step 1: Collect data in n cycles. In each cycle, the absorption coefficient b ji and wavelength λi Correspondingly, i=1,2…N, we get j The corresponding coefficient k j and the absorption index α j , j = 1, 2…n, α ff =(α j ) min , α bb =(α j ) max , n is an integer not less than 2;

[0012] Step 2: Based on the data collected in each cycle, coefficient k j , α ff and α bb ,use Get the value of each cycle T j The corresponding k jff ;

[0013] Step 3: Get the value of each cycle T j The corresponding k jbb =k j -k jff ;

[0014] Step 4: Get the value of each cycle T j The corresponding biomass contribution to black carbon concentration BC jbb,% , fossil fuels contribute to black carbon concentrations BC jff,% ;

[0015] , ;

[0016] MAE bb,BC 、MAE ff,BC are the mass absorption cross sections of black carbon emitted from the combustion of biomass and fossil fuels, respectively.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Source parsing is more accurate;

[0019] 1. Use multiple wavelengths, such as 10, to obtain the fossil fuel absorption index and biomass absorption index through statistical methods, and then derive the contribution ratio of pollution sources;

[0020] 2. Provide a method to obtain the biomass absorption index and fossil fuel absorption index to avoid the estimation error caused by using fixed values. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0022] Figure 1 4 is a flow chart of a method for analyzing the source of black carbon according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] Figure 1 The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to explain the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will appreciate that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents.

[0024] Example 1.

[0025] The method for analyzing the source of black carbon in the embodiment of the present invention is as follows: Figure 1 As shown, the method for analyzing the source of black carbon includes the following steps.

[0026] Step 1: Collect data in n cycles. In each cycle, the absorption coefficient b ji and wavelength λ i Correspondingly, i=1,2…N, N is an integer not less than 3, and n is an integer not less than 2.

[0027] Using b(λ)=k·λ -α , the fitting results are related to each cycle T j The corresponding coefficient k j and the absorption index α j , j = 1, 2…n, α ff =(α j ) min , α bb =(α j ) max , that is, n cycles correspond to α bb , α ff .

[0028] Step 2: Based on the data collected in each cycle, coefficient k j and α bb ,use Get the value of each cycle T j The corresponding k jff .

[0029] Step 3: Get the value of each cycle T j The corresponding k jbb =k j -k jff .

[0030] Step 4: Get the value of each cycle T j The corresponding biomass contribution to black carbon concentration BC jbb,% , fossil fuels contribute to black carbon concentrations BC jff,% .

[0031] , ;

[0032] MAE bb,BC 、MAE ff,BC are the mass absorption cross sections of black carbon emitted from the combustion of biomass and fossil fuels, respectively.

[0033] Example 2.

[0034] This is an application example of the method for analyzing the source of black carbon according to Example 1 of the present invention.

[0035] In this application example, Figure 1 As shown, the method includes the following steps.

[0036] Step 1: Collect data in 1440 cycles (each cycle is 1 minute). In each cycle, the absorption coefficient b ji and wavelength λ i Correspondingly, i=1,2…10, N=10, the specific wavelength is λ 1 =0.37μm,λ 2 =0.43μm,λ 3 =0.47μm,λ 4 =0.52μm,λ 5 =0.565μm,λ 6 =0.59μm,λ 7 =0.66μm, λ 8 =0.76μm,λ 9 =0.88μm,λ 10 =0.95μm, j=1,2…1440, the total time of 1440 cycles is 24 hours.

[0037] According to the absorption coefficient b collected in each cycle ji and wavelength λ i , using b(λ)=k·λ -α , the fitting results are related to each cycle T j The corresponding coefficient k j and the absorption index α j, j=1,2…1440.

[0038] The obtained ji , coefficient k j , absorption index α j and wavelength λ i The data is shown in the following table (partial data).

[0039] .

[0040] From the table above, 1440 cycles correspond to α ff =(α j ) min =1.08,α bb =(α j ) max =2.28.

[0041] Step 2: According to the absorption coefficient b collected in each cycle ji and wavelength λ i , coefficient k j , α ff and α bb ,use , the fitting results in the acquisition of each cycle T j The corresponding k jff .

[0042] For example, in the first cycle T 1 , using b 11 -b 110 ,λ 1 -λ 10 , and α bb =2.28, α ff =1.08 and k 1 =20538613, using the calculation data in the following table.

[0043] .

[0044] The fitting result is k 1ff =19864873.

[0045] Step 3: Get the value of each cycle T j The corresponding k jbb =k j -k jff .

[0046] For example, in the first cycle T 1 , we get k 1bb = k 1 -k 1ff =673740.

[0047] Step 4: Get the value of each cycle T j The corresponding biomass contribution to black carbon concentration BC jbb,% , fossil fuels contribute to black carbon concentrations BC jff,% .

[0048] , .

[0049] For example, in the first cycle T 1 , according to λ 9 =0.88μm, α ff =1.08,α bb =2.28, k 1ff =19864873,k 1bb =673740,MAE ff , BC ≈MAE bb , BC , get BC 1bb,% =3.8%, BC 1ff,% =96.2%.

[0050] Similarly, the contribution ratios of biomass and fossil fuels corresponding to other periods within the 1440 periods are obtained.

[0051] Example 3.

[0052] The application example of the method for analyzing the source of black carbon according to Example 1 of the present invention is different from Example 2.

[0053] Each cycle lasts 5 minutes, and the data in 288 cycles (n=288, the total time of 288 cycles is 24 hours) are used to obtain α ff and α bb .

[0054] Example 4.

[0055] The application example of the method for analyzing the source of black carbon according to Example 1 of the present invention is different from Example 2.

[0056] Each cycle lasts 60 minutes, and the data in 168 cycles (n=168) are used to obtain α ff and α bb The total time for 168 cycles is 7 days.

[0057] The above embodiment merely exemplifies the selection of 10 wavelengths. Of course, the number of wavelengths may be 7 or other numbers, but the wavelength λ=0.88 μm must be included.

Claims

1. A method for analyzing the source of black carbon, comprising the following steps: Step 1: Collect data in n cycles, and in each cycle T j Internal absorption coefficient b ji and wavelength λ i Correspondingly, i=1,2…N, we get j The corresponding coefficient k j and the absorption index α j , j = 1, 2…n, α ff =(α j ) min , α bb =(α j ) max , n is an integer not less than 2; Step 2: Based on the data collected in each cycle, coefficient k j , α ff and α bb ,use Get the value of each cycle T j The corresponding k jff ; Step 3: Get the value of each cycle T j The corresponding k jbb =k j -k jff ; Step 4: Get the value of each cycle T j The corresponding biomass contribution to black carbon concentration BC jbb,% , fossil fuels contribute to black carbon concentrations BC jff,% ; ， ； MAE bb,BC 、MAE ff,BC are the mass absorption cross sections of black carbon emitted from the combustion of biomass and fossil fuels; In the contribution calculation in step 4, λ=0.88μm.

2. The method for analyzing the source of black carbon according to claim 1, characterized in that: In step 1, according to the absorption coefficient b of each cycle ji and wavelength λ i , using b(λ)=k·λ -α , α is the absorption index, and the fitting result is related to the period T j The corresponding coefficient k j and the absorption index α j .

3. The method for analyzing the source of black carbon according to claim 1, characterized in that: Within each period, the wavelengths are λ1=0.37μm, λ2=0.43μm, λ3=0.47μm, λ4=0.52μm, λ5=0.565μm, λ6=0.59μm, λ7=0.66μm, λ8=0.76μm, λ9=0.88μm, λ 10 =0.95μm.

4. The method for analyzing the source of black carbon according to claim 1, characterized in that: The total time of n cycles shall not be less than 24 hours.

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