title: Chemical characterization of PM1.0aerosol in Delhi and source apportionment using positive matrix factorization.
abstract: Fine aerosol fraction (particulate matter with aerodynamic diameter <= 1.0 μm (PM)1.0) over the Indian Institute of Technology Delhi campus was monitored day and night (10 h each) at 30 m height from November 2009 to March 2010. The samples were analyzed for 5 ions (NH4+, NO3-, SO42-, F-, and Cl-) and 12 trace elements (Na, K, Mg, Ca, Pb, Zn, Fe, Mn, Cu, Cd, Cr, and Ni). Importantly, secondary aerosol (sulfate and nitrate) formation was observed during dense foggy events, supporting the fog-smog-fog cycle. A total of 76 samples were used for source apportionment of PM mass. Six factors were resolved by PMF analyses and were identified as secondary aerosol, secondary chloride, biomass burning, soil dust, iron-rich source, and vehicular emission. The geographical location of the sources and/or preferred transport pathways was identified by conditional probability function (for local sources) and potential source contribution function (for regional sources) analyses. Medium- and small-scale metal processing (e.g. steel sheet rolling) industries in Haryana and National Capital Region (NCR) Delhi, coke and petroleum refining in Punjab, and thermal power plants in Pakistan, Punjab, and NCR Delhi were likely contributors to secondary sulfate, nitrate, and secondary chloride at the receptor site. The agricultural residue burning after harvesting season (Sept-Dec and Feb-Apr) in Punjab, and Haryana contributed to potassium at receptor site during November-December and March 2010. The soil dust from North and East Pakistan, and Rajasthan, North-East Punjab, and Haryana along with the local dust contributed to soil dust at the receptor site, during February and March 2010. A combination of temporal behavior and air parcel trajectory ensemble analyses indicated that the iron-rich source was most likely a local source attributed to emissions from metal processing facilities. Further, as expected, the vehicular emissions source did not show any seasonality and was local in origin.
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Delhi, Delhi, India.
authors.lastname: Jaiprakash
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Delhi, Delhi, India.
authors.forename: Amrita
authors.initials: A
authors.lastname: Singhai
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Delhi, Delhi, India. gazalahabib@gmail.com.
authors.forename: Gazala
authors.identifier: http://orcid.org/0000-0003-3598-3548
authors.initials: G
authors.lastname: Habib
authors.affiliation: Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India.
authors.forename: Ramya Sunder
authors.initials: RS
authors.lastname: Raman
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, India.
authors.forename: Tarun
authors.initials: T
authors.lastname: Gupta
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring; D007194:India; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter
keywords: Biomass burning; Positive matrix factorization (PMF); Secondary aerosol; Source apportionment