title: Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.
abstract: This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions.
authors: Physical Research Laboratory, Ahmedabad 380 009, India.
authors: Prashant
authors: P
authors: Rajput
authors: Physical Research Laboratory, Ahmedabad 380 009, India. Electronic address: sarin@prl.res.in.
authors: M M
authors: MM
authors: Sarin
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000383:Agriculture; D002244:Carbon / Q000032:analysis*; D007194:India; D009930:Organic Chemicals / Q000032:analysis*; D011786:Quality Control; D014866:Waste Products
chemical_list: D000336:Aerosols; D009930:Organic Chemicals; D014866:Waste Products; D002244:Carbon
keywords: Non-polar organic aerosol; Organic mass-to-organic carbon ratio; Polar organic aerosol; Post-harvest agricultural-waste burning emission