Quantification of organic carbon and black carbon emissions, distribution, and carbon variation in diverse vegetative ecosystems across India

Abstract

Black Carbon (BC) and Organic Carbon (OC) are the principal chemical aerosol components generated during combustion, both of which play a key role in air pollution, human health and climate change. Several studies of OC and BC have been conducted over India to assess the contribution from household and fossil fuel-based sources; however, studies on their emissions and their contribution from forest and cropland fires are quite limited. To address this issue, as part of this research, we derived a vegetation burning-based inventory of BC and OC aerosols over India at a resolution of 250 m × 250 m. Using a consumed biomass technique, we estimated emissions based on updated emission factor estimates. During the fire season in India (March–June), the mean OC and BC emissions were 2.1 ± 5.2 × 1013 kg per year and 1.8 ± 4.4 × 1012 kg per year, respectively. Andhra Pradesh had the highest total carbonaceous aerosol emissions during the study period. Forest fires were prevalent in the northeastern states, while agricultural fires were prevalent in Gujarat, Chhattisgarh, Odisha, Madhya Pradesh, Bihar, Tripura, Uttar Pradesh, and Andhra Pradesh. The previous inventory, conducted at a coarser resolution (25 km × 25 km), overestimated open burning by 5 Mt. Our results were highly correlated with global bottom-up model values, especially the Fire Inventory (FINN). Our analysis showed that vegetative burning contributed 80.32% of the total carbon stock, with agricultural burning being the largest source of vegetative burning. Based on these findings, measures and strategies to control agricultural burning which would reduce significantly the total emissions of BC and OC with implications to improvement in air quality, human health and climate should be planned.