Multi-pollutant emissions from the burning of major agricultural residues in China and the related health-economic effects

Abstract

Abstract. Multi-pollutants in smoke particulate matter (SPM) were identified and quantified for the biomass burning of five major agricultural residues (wheat, rice, corn, cotton, and soybean straw) in China by an aerosol chamber system combined with various measurement techniques. The primary emission factors (EFs) for PM1. 0 and PM2. 5 are 3.04–12.64 and 3.25–15.16 g kg−1. Organic carbon (OC), elemental carbon (EC), water-soluble inorganics (WSIs), water-soluble organic acids (WSOAs), water-soluble amine salts (WSAs), trace mineral elements (THMs), polycyclic aromatic hydrocarbons (PAHs), and phenols in smoke PM1. 0/PM2. 5 are 1.34–6.04/1.54–7.42, 0.58–2.08/0.61–2.18, 0.51–3.52/0.52–3.81, 0.13–0.64/0.14–0.77, (4.39–85.72/4.51–104.79) × 10−3, (11.8-51.1/14.0-131.6) × 10−3, (1.1–4.0/1.8–8.3) × 10−3, and (7.7–23.5/9.7–41.5) × 10−3 g kg−1, respectively. Black carbon (BC) mainly exists in PM1. 0; heavy-metal-bearing particles favour residing in the range of smoke PM1. 0−2. 5, which is also confirmed by individual particle analysis. With respect to the five scenarios of burning activities, the average emissions and overall propagation of uncertainties at the 95 % confidence interval (CI) of SPM from agricultural open burning in China in 2012 were estimated to be 1005.7 (−24.6, 33.7 %), 901.4 (−24.4, 33.5 %), 432.4 (−24.2, 33.5 %), 134.2 (−24., 34.0 %), 249.8 (−25.4, 34.9 %), 25.1 (−33.3, 41.4 %), 5.8 (−30.1, 38.5 %), 8.7 (−26.6, 35.6 %), 0.5 (−26.0, 34.9 %), and 2.7 (−26.1, 35.1 %) Gg for PM2. 5, PM1. 0, OC, EC, WSI, WSOA, WSA, THM, PAHs, and phenols , respectively. The emissions were further spatio-temporally characterized using a geographic information system (GIS) in different regions in the summer and autumn post-harvest periods. It was found that less than 25 % of the total emissions were released during the summer harvest, which was mainly contributed by the North Plain and the centre of China, especially Henan, Shandong, and Anhui, which are the top three provinces regarding smoke particle emissions. Flux concentrations of primarily emitted smoke PM2. 5 that were calculated using the box-model method based on five versions of emission inventories all exceed the carcinogenic-risk permissible exposure limits (PEL). The health impacts and health-related economic losses from the smoke PM2. 5 short-term exposure were assessed. The results show that China suffered from 7836 cases (95,% CI: 3232, 12362) of premature mortality and 7 267 237 cases (95 % CI: 2 961 487, 1 130 784) of chronic bronchitis in 2012, which led to losses of USD 8822.4 million (95 % CI: 3574.4, 13 034.2) or 0.1 % of the total GDP. We suggest that the percentage of open-burnt crop straw in the post-harvest period should be cut down by over 97 % to ensure a reduction in carcinogenicity risk, especially in the North Plain and the northeast, where the emissions should decrease at least by 94 % to meet the PEL. With such emission control, over 92 % of the mortality and morbidity attributed to agricultural fire smoke PM2. 5 can be avoided in China.

Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

“…Akagi et al (2011) updated the emission data for 14 types of biomass burning, and newly identified species were included. Since biomass types and combustion conditions may differ in different studies, reported emission factors are highly variable, especially for agricultural residue burning (Li et al, 2007(Li et al, , 2017Cao et al, 2008;Zhang et al, 2008;Yokelson et al, 2011;Brassard et al, 2014;Sanchis et al, 2014;Ni et al, 2015;Kim Oanh et al, 2015;Stockwell et al, 2016;Bruns et al, 2017;Tkacik et al, 2017). Moreover, previous studies on agricultural residue burning were mostly carried out near fire spots or in chambers with low dilution ratios.…”

“…where ω fuel and ω ash are mass fractions of carbon in the dry fuel and its ash, and m fuel and m ash are the mass of dry fuel Ni et al (2015), PM corresponds to PM 2.5 ; i Li et al (2017), PM corresponds to PM 1 ; j Zhang et al (2008).…”

Estimating the open biomass burning emissions in central and eastern China from 2003 to 2015 based on satellite observation

“…From the 1970s (Crutzen et al, 1979), emission estimation of biomass burning has been a research hot topic from global (Seiler and Crutzen, 1980;Levine et al, 1995;Liousse et al, 1995;Bond et al, 2004;Randerson et al, 2012;Kaiser et al, 2012) to regional scale Liousse et al, 2010;Li et al, 2017). China is suffering from severe air pollution with 100 million tons of biomass open burned each year (Zhang et al, 2015).…”

Response to referee1

“…From the 1970s (Crutzen et al, 1979), emission estimation of biomass burning has been a research hot topic from global (Seiler and Crutzen, 1980;Levine et al, 1995;Liousse et al, 1995;Bond et al, 2004;Randerson et al, 2012;Kaiser et al, 2012) to regional scale Liousse et al, 2010;Li et al, 2017). China is suffering from severe air pollution with 100 million tons of biomass open burned each year (Zhang et al, 2015).…”

“…In addition, most previous studies have adopted the topdown method (Seiler and Crutzen, 1980) to estimate OBB emissions by national or provincial statistical data, and then the total emission amounts of pollutants were re-allocated in grids by population, land cover area or even equal sharing, which is one of the key reasons for the high uncertainties of OBB emission inventories (Streets et al, 2003;Klimont and Streets, 2007;Gadde et al, 2009;He et al, 2011;Zhou et al, 2015Zhou et al, , 2017. Quantitative estimation of biomass burning was highly improved by the satellite observations of fire burned area or active burning fires (Freitas et al, 2005;Wooster et al, 2005;Roy et al, 2008;Giglio et al, 2008;Reid et al, 2009;Sofiev et al, 2009;Liousse et al, 2010;Huang et al, 2012a;Li et al, 2016). The improvement of spatial-temporal distribution evolution was achieved by active fire products (e.g., the AVHRR fire count product, Setzer and Pereira, 1991; Moderate Resolution Imaging Spectroradiometer (MODIS) active fire satellite products, Cooke et al, 1996;and VIRS fire count product, Ito and Akimoto, 2007).…”