This is an open access article under the terms of the Creative Commons...

Usmani, M., A. Kondal, J. Wang, and A. Jutla (2020), This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modificatio, Usmani Et Al., 1, 9.

Intensification of smog episodes, following harvesting of paddy crops in agricultural plains of the Indus basin in the Indian subcontinent, are often attributed to farming practice of burning standing stubble during late autumn (October, November) months. Biomass burning (paddy stubble residual) is a preferred technique to clear farmlands for centuries by farmers in that basin. However, despite stable agricultural landholding and yield, smog is being increasingly associated with burning agricultural biomass, thus creating a paradox. Here, we show that the concentration of smog (NOx, PM2.5, SO2) in the ambient air exceeds the safe threshold limits throughout the entire year in the region. This study argues that agricultural biomass burning is an ephemeral event in the basin that may act as a catalyst to a deteriorated air quality in the entire region. Results further demonstrate that simultaneous saturation of air pollutants along with high ambient moisture content and low wind speeds following the monsoon season are strongly related to aggravated smog events. Findings from this study should help make holistic mitigation and intervention policies to monitor air quality for sustainability of public health in agricultural regions where farming activities are a dominant economic driver for society. Plain Language Summary Northern central Indus and northwestern Ganges basin experienced intense smog incidents post‐monsoon‐post harvesting season. Smog in this region is primarily characterized by premature mortality, low visibility, eye irritation, and damage to crops, but the recent intensification of these episodes had raised an overdue concern. Due to the specific temporal existence of these episodes, it has been associated with the practice of residual crop burning. Using in‐situ and remote sensing data, we have shown that significantly high concentration of smog in the ambient air exists throughout the year. Simultaneously, stubble burning is a brief event that can only affect on a small spatial and temporal scales. Along with low wind speed in October and November (concerned months), we have found a considerable increase in dew point temperatures in last ten years, indicating a possible favorable condition for smog and entrapment of air pollutants. We expect that results from this work will provide a comprehensive discussion to manage air quality in the Indus basin.

Research Program: 
Applied Sciences Program (ASP)
Atmospheric Composition
Atmospheric Composition Modeling and Analysis Program (ACMAP)
Radiation Science Program (RSP)
Tropospheric Composition Program (TCP)