Chawala Pratika, Priyan R Shanmuga, Sm Shiva Nagendra
Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, 600 036, India.
Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, 600 036, India.
Environ Res. 2023 Mar 1;220:115125. doi: 10.1016/j.envres.2022.115125. Epub 2022 Dec 30.
Indo-Gangetic Plains (IGP) experiences high loading of particulate and gaseous pollutants all year around and is considered to be the most polluted regions of India. Understanding the effect of landscape determinants on air pollution in IGP regions is crucial to make its environment sustainable. We examined satellite retrievals of OMI NO and SO, and MODIS AOD to analyse the long-term trend, spatio-seasonal pattern and dynamics of aerosols, NO and SO over three IGP regions, namely Upper Indo-Gangetic plain (UIGP), Middle Indo-Gangetic plain (MIGP) and Lower Indo-Gangetic plain (LIGP) over the period 2005-2019. IGP experienced an overall increment in AOD (R = 0.63) and SO (R = 0.67) values, with LIGP (AOD, R = 0.8 & SO, R = 0.8) experiencing the largest rate of enhancement. The levels of NO (R = 0.2) experienced a decrement after 2012 (owing to implementation of vehicle emission policy) except in MIGP, with UIGP (R = 0.23) exhibiting the largest rate of decrement. Seasonal heterogeneity in the nature of sources was observed over IGP regions. AOD (0.61 ± 0.1) and NO value (3.82 ± 0.98 × 10 molecules/cm) were found highest during post-monsoon in UIGP owing to crop residue burning activity. The value of NO (3.8 ± 1.4 × 10 molecules/cm) in MIGP was found highest during pre-monsoon due to high consumption of coal in power plants for summer cooling demand. The highest SO level (0.09 ± 0.06 DU) was observed during post-monsoon in UIGP, as a large number of brick kilns are fired during this period. Correlations among landscape determinants and pollutants revealed that topography is the dominant variable that affect the spatial pattern of AOD compared to vegetation and land use. Lower elevation tends to have high AOD values compared to higher elevation. Vegetation-AOD relationship showed an inverse association in IGP regions and is influenced by factors such as seasonal meteorology and size of the airborne particles. Vegetation possesses positive relationship with SO and NO, implying no pollution abatement effect on SO and NO pollutants. Built-up change has deteriorating effect as well as quenching effect on pollutants. Increase in built terrain have deteriorated the air quality in UIGP whereas it favored in suppressing the aerosol level in LIGP.
印度-恒河平原（IGP）全年都承受着高负荷的颗粒物和气态污染物，被认为是印度污染最严重的地区。了解景观决定因素对IGP地区空气污染的影响对于使其环境可持续发展至关重要。我们研究了OMI NO和SO以及MODIS AOD的卫星反演数据，以分析2005 - 2019年期间IGP的三个地区，即上印度-恒河平原（UIGP）、中印度-恒河平原（MIGP）和下印度-恒河平原（LIGP）上气溶胶、NO和SO的长期趋势、时空季节模式及动态变化。IGP的AOD（R = 0.63）和SO（R = 0.67）值总体呈上升趋势，其中LIGP（AOD，R = 0.8；SO，R = 0.8）的增长速率最大。除了MIGP，2012年后NO水平（R = 0.2）呈下降趋势（由于实施了车辆排放政策），UIGP（R = 0.23）的下降速率最大。在IGP地区观察到源的性质存在季节性异质性。由于作物秸秆焚烧活动，UIGP的AOD（0.61±0.1）和NO值（3.82±0.98×10分子/cm）在季风后最高。由于夏季制冷需求，发电厂大量消耗煤炭，MIGP的NO值（3.8±1.4×10分子/cm）在季风前最高。UIGP在季风后观测到最高的SO水平（0.09±0.06 DU），因为在此期间大量砖窑点火。景观决定因素与污染物之间的相关性表明，与植被和土地利用相比，地形是影响AOD空间格局的主导变量。与高海拔地区相比，低海拔地区往往具有较高的AOD值。植被与AOD的关系在IGP地区呈负相关，并受季节性气象和空气中颗粒物大小等因素影响。植被与SO和NO呈正相关，这意味着对SO和NO污染物没有减排作用。建成区变化对污染物既有恶化作用也有抑制作用。建成地形的增加恶化了UIGP的空气质量，而在LIGP则有利于抑制气溶胶水平。
