Estimating the open biomass burning emissions in central and eastern China from 2003 to 2015 based on satellite observation
Authors: Wu Jian , Kong Shaofei , Wu Fangqi , Cheng Yi , Zheng Shurui , Yan Qin , Zheng Huang , Yang Guowei , Zheng Mingming , Liu Dantong , Zhao Delong , Qi Shihua 
Published: August 2018

Abstract. Open biomass burning (OBB) has significant impacts on air
pollution, climate change and potential human health. OBB has gathered wide
attention but with little focus on the annual variation of pollutant
emission. Central and eastern China (CEC) is one of the most polluted
regions in China. This study aims to provide a state-of-the-art estimation
of the pollutant emissions from OBB in CEC from 2003 to 2015, by adopting
the satellite observation dataset – the burned area product (MCD64Al) and the
active fire product (MCD14 ML) – along with local biomass data (updated biomass loading
data and high-resolution vegetation data) and local emission factors. The
successful adoption of the double satellite dataset for long-term estimation of
pollutants from OBB with a high spatial resolution can support the assessing
of OBB on regional air quality, especially for harvest periods or dry
seasons. It is also useful to evaluate the effects of annual OBB management
policies in different regions. Here, monthly emissions of pollutants were
estimated and allocated into a 1×1 km spatial grid for four types of
OBB including grassland, shrubland, forest and cropland. From 2003 to 2015,
the emissions from forest, shrubland and grassland fire burning had an annual
fluctuation, whereas the emissions from crop straw burning steadily
increased. The cumulative emissions of organic carbon (OC), elemental carbon
(EC), methane (CH4), nitric oxide (NOx), non-methane volatile
organic compounds (NMVOCs), sulfur dioxide (SO2), ammonia (NH3),
carbon monoxide (CO), carbon dioxide (CO2) and fine particles
(PM2.5) were 3.64×103, 2.87×102,
3.05×103, 1.82×103, 6.4×103,
2.12×102, 4.67×102, 4.59×104,
9.39×105 and 4.13×103 Gg in these years,
respectively. Crop straw burning was the largest contributor for all
pollutant emissions, by 84 %–96 %. For the forest, shrubland and
grassland fire burning, forest fire burning emissions contributed the most,
and emissions from grassland fire were negligible due to little grass coverage
in this region. High pollutant emissions concentrated in the connection area
of Shandong, Henan, Jiangsu and Anhui, with emission intensity higher than
100 tons per square kilometer, which was related to the frequent
agricultural activities in these regions. Peak emission of pollutants
occurred during summer and autumn harvest periods including May, June, September
and October, during which ∼50 % of the total pollutant
emissions were emitted in these months. This study highlights the importance
of controlling the crop straw burning emissions. From December to March, the
crop residue burning emissions decreased, while the emissions from forest,
shrubland and grassland exhibited their highest values, leading to another
small peak in emissions of pollutants. Obvious regional differences in seasonal
variations of OBB were observed due to different local biomass types and
environmental conditions. Rural population, agricultural output, economic
levels, local burning habits, social customs and management policies were
all influencing factors for OBB emissions.