Role of atmospheric ammonia in the formation of inorganic secondary particulate matter: A study at Kanpur, India

This study has investigated the chemical association among acidic gases, ammonia and secondary inorganic aerosols based on hourly measurements in a tropical urban atmosphere. 2-and HNO 3 into NO 3 -was observed to be sensitive to changes in temperature and relative humidity, respectively. The study area experienced ambient relative humidity, which was higher than the estimated deliquescence relative humidity of NH 4 NO 3 most of the time during the measurement period. As a result, the NH 4 NO 3 formation was thermodynamically favorable during both daytime and nighttime. However, NH 4 Cl formation was not favored under ammonia-poor conditions. It was observed that biomass burning could trigger nitrate and chloride formation in the ambient air.

Section: Gas-to-particle Formationcontrasting

confidence: 99%

Insights into Chemical Coupling among Acidic Gases, Ammonia and Secondary Inorganic Aerosols

Behera

Betha

Balasubramanian

2013

“…Nitrate (NO 3 -) daily mean and maximum concentrations in PM 10-2.5 and PM 2.5 vary from 0.64 to 2.05 and from 0.09 to 0.24 µg/m 3 , respectively. The low mass concentration of NO 3 -in the fine mode may be attributed to the formation of instable ammonium nitrate during warm season (Querol et al, 2004;Sharma et al, 2007;Theodosi et al, 2011). In fact, the temperature was always above 20°C during the day (Malaguti et al, 2013) favoring the well-known phenomenon of NH 4 NO 3 evaporation from filters during sampling.…”

Section: Chemical Characterizationmentioning

confidence: 98%

Chemical Composition of Fine and Coarse Aerosol Particles in the Central Mediterranean Area during Dust and Non-Dust Conditions

Malaguti

Mircea

Torretta

et al. 2015

A two-month field campaign was carried out from May to June 2010 at a remote site (Trisaia ENEA Research Centre) in the Southern Italy aiming to identify and quantify the changes of aerosol chemical composition in the presence of Saharan dust. The 24-hr PM 10 and PM 2.5 filter samples were analyzed by mass, carbonaceous species, inorganic ions and elemental composition. Saharan dust transport events were identified with two approaches: one recommended by EC (2011) and one based on indicators derived from measurements. Three indicators were used: PM 2.5 /PM 10 mass concentrations ratio, Ca/Al ratio and Al concentration. Based on these criteria, four Saharan dust transport events were identified, but only one had elevated dust concentration and leaded to an exceedance of the European short-term (24 hour) limit value of 50 µg/m 3 for PM 10 (June 16 th ). The comparison of chemical composition of fine and coarse aerosol fractions during dust and non-dust conditions shows that the presence of dust increases NH 4 and nssSO 4 concentrations in the fine fraction and NO 3 and nssSO 4 concentrations in the coarse fraction. OC and EC concentrations also increase in the fine fraction during dust transport. The uptake of primary and secondary species, inorganic and organic, by dust particles changes their composition and, thus, their properties and this may have implications for human health and climate change.

“…The IIT Kanpur campus, located on the Grand Trunk Road, is about 17 km away from the city center of Kanpur (Fig. 1, after Sharma et al, 2007), where automobiles and a power plant are the principal causes of air pollution, supplemented by biomass burning in winter . The city is mostly encircled by vegetation and agricultural fields.…”

Section: Site Locationmentioning

confidence: 99%

“…Location of Kanpur city showing the study site and major sources. After Sharma et al, (2007). concentration in the diameter range of 15-700 nm, denoted as Md 15-700nm (2) their corresponding size distribution, and (3) BC mass concentration (M BC ), in Kanpur, an industrial town in the Indo-Gangetic plain.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Diurnal and Seasonal Variation of Submicron Outdoor Aerosol Mass and Size Distribution in a Northern Indian City and Its Correlation to Black Carbon

Baxla

Roy

Gupta

et al. 2009

The seasonal and diurnal behavior of atmospheric submicron aerosol was studied in the northern Indian city of Kanpur in the Indo Gangetic Plain during July 2006-May 2007. The size distribution and mass concentration of the aerosol in the range of 15-700 nm was measured using a scanning mobility particle sizer (SMPS). Simultaneously, black carbon (BC) measurement was made using an aethalometer. The measurements were recorded for four different seasons, viz. monsoon, post-monsoon, winter and pre-monsoon. The diurnal variation of BC and submicron aerosol mass followed very similar trends in all the seasons. This is evident by the fact that BC had strong positive correlation with the submicron aerosol mass (0.83 ≤ R ≤ 0.96, where R is the Pearson's correlation coefficient). Both peaked once in the morning [07:00-09:00 local time (LT)], and once in the night (20:00-22:00 LT). The peak concentrations varied from season to season, which could be attributed to seasonal variation in anthropogenic activity, traffic movement and atmospheric boundary layer conditions. The background aerosol number concentration in winter (~10 5 #/cm 3 ) was an order of magnitude higher than that observed in other seasons (~10 4 #/cm 3 ); and on a foggy day in the winter, it was twice as high as that seen on a clear winter day. The fraction (F BC ) of the BC mass concentration in the submicron aerosol was observed to be highest in monsoon (0.18 ± 0.13), followed by pre-monsoon (0.08 ± 0.02) and post-monsoon (0.05 ± 0.01), with the lowest in winter (0.03 ± 0.01).