Indian Institute of Tropical Meteorology, New Delhi, India.
Aryabhatta Research Institute of Observational Sciences, Nainital, India.
Sci Total Environ. 2015 Jul 15;521-522:431-45. doi: 10.1016/j.scitotenv.2015.03.083. Epub 2015 Apr 8.
Particulate matter (PM2.5) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO4(2-) and NO3(-)) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM2.5 samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO4(2-) and NO3(-)). Furthermore, continuous (online) measurements of PM2.5 (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM2.5 (online) range from 18.2 to 500.6μgm(-3) (annual mean of 124.6±87.9μgm(-3)) exhibiting higher night-time (129.4μgm(-3)) than daytime (103.8μgm(-3)) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO3(-)and SO4(2-), which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R(2)=0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~1.8-2.0Kday(-1)) due to agricultural burning effects during the 2012 post-monsoon season.
2012 年 1 月至 12 月，在印度德里采集了颗粒物（PM2.5）样本，并对其进行了碳质气溶胶和无机离子（SO4(2-)和 NO3(-)）分析，以研究大气化学变化、燃烧源和长程传输的影响。使用中流量空气采样器（offline）测量 PM2.5 样本，并通过重量分析法（gravimetrically）对碳质气溶胶（有机碳，OC；元素碳，EC）和无机离子（SO4(2-)和 NO3(-)）进行分析。此外，还进行了 PM2.5（通过 Beta 衰减分析仪进行连续在线测量）、黑碳（BC）质量浓度（通过 Magee 科学 Aethalometer 进行连续在线测量）和一氧化碳（通过 CO 分析仪进行连续在线测量）的连续在线测量。PM2.5（online）的范围为 18.2 至 500.6μg/m(-3)（年平均值为 124.6±87.9μg/m(-3)），夜间（129.4μg/m(-3)）浓度高于白天（103.8μg/m(-3)）。在线浓度在夜间和白天分别比离线浓度低 38%和 28%。一般来说，BC、OC、NO3(-)和 SO4(2-)的在线浓度在夜间较大，且在后季风期和冬季的差异较大。OC 和 EC 之间的高相关性（R(2)=0.74）以及 OC/EC 分别为 7.09（白天）和 4.55（夜间），表明生物质燃烧排放（燃烧木材和农业废弃物）以及二次有机气溶胶形成在白天具有重要影响。集中加权轨迹（CWT）分析表明，碳质气溶胶和污染物的潜在来源是城市环境中的本地排放物，以及后季风期印度西北部农业燃烧产生的烟雾。BC 辐射强迫估算结果表明，由于 2012 年后季风季节农业燃烧的影响，大气加热率非常高（约 1.8-2.0K/day）。
