Infrequent occurrence of new particle formation at a semi-rural location, Gadanki, in tropical Southern India

Kanawade, Vijay P.; Shika, S.; Pöhlker, Christopher; Rose, D.; Suman, Mayank; Gadhavi, Harish; Kumar, Ashwini; Nagendra, S.M. Shiva; Ravikrishna, R.; Yu, Huan; Sahu, L. K.; Jayaraman, A.; Andreae, Meinrat O.; Pöschl, Ulrich; Gunthe, Sachin S.

doi:10.1016/j.atmosenv.2014.05.046

Cited by 27 publications

(11 citation statements)

References 49 publications

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“…showed that NPF events were observed in Qingdao City, where the high concentration of gaseous pollutants might offset the effect of a large CS. In a semirural location in India, Kanawade et al (2014) also demonstrated that NPF events were not limited by a low value of CS alone. Therefore, the detailed analysis of sinks and sources at a specific site is of great importance for NPF.…”

Section: Condensation Sinks and Sources Of Npfmentioning

confidence: 98%

Investigation of new particle formation at the summit of Mt. Tai, China

Lv¹,

Sui²,

Chen³

et al. 2018

Atmos. Chem. Phys.

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Abstract. To date, few comprehensive field observations of new particle formation (NPF) have been carried out at mountaintop sites in China. In this study, simultaneous measurements of particle size distribution, trace gases, meteorological parameters, and mass concentration and chemical composition of PM 2.5 were performed at the summit of Mt. Tai (1534 m a.s.l.) from 25 July to 24 August 2014 (Phase I), 21 September to 9 December 2014 (Phase II), and 16 June to 7 August 2015 (Phase III) to investigate characteristics and favorable conditions of NPF in a relatively clean mountaintop environment. The NPF events were identified based on particle size distribution measured by the neutral cluster and air ion spectrometer (NAIS), and 66 such events were observed during a period of 164 days -corresponding to an occurrence frequency of 40 %. The formation rates of 3 nm particles (J 3 ) and growth rates were in the ranges of 0.82-25.04 cm −3 s −1 and 0.58-7.76 nm h −1 , respectively. On average, the condensation sink (CS), O 3 concentration, air temperature, and relative humidity were lower, whereas the SO 2 concentration was higher on NPF days than that on non-NPF days. The CS on Mt. Tai was at a low level and lower CS was critical for NPF. NPF events were common when wind came from the east-southeast and west-southwest, which was probably associated with relatively lower CS in the east-southeast and higher SO 2 concentration in the west-southwest. O 3 was not a governing factor for NPF in this study, and a high level of NO x concentration might be responsible for the decreased O 3 concentration on NPF days. Three categories of backward trajectories were classified, among which the continental air mass was the majority. The continental air mass passing through more polluted areas (denoted as Type I) favored NPF because of enhanced SO 2 concentration and potential ammonia with it. An in-depth analysis of SO 2 indicated that sulfuric acid was a dominant precursor on Mt. Tai; meanwhile, biogenic organics released from ambient forests in warm seasons and anthropogenic volatile organic compounds emitted from domestic heating in cold seasons also promoted NPF.

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Section: Condensation Sinks and Sources Of Npfmentioning

confidence: 98%

Investigation of new particle formation at the summit of Mt. Tai, China

Lv¹,

Sui²,

Chen³

et al. 2018

Atmos. Chem. Phys.

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“…Previous studies where a similar instrument was used have reported that pronounced diurnal variations in N T are strongly coupled with diurnal variations in meteorological variables, especially mixing layer depth Raatikainen et al, 2014;Du et al, 2013). The ab- sence of pronounced diurnal variations in N T at this particular site may be a result of weak dependence of coarse-mode TAP concentrations on meteorological parameters combined with persistent rainfall causing the washout of these particles (Radke et al, 1980;Raatikainen et al, 2014;Kanawade et al, 2014;Shika et al, 2016). This also indicates the absence of any strong and localized source of anthropogenic emissions during most of the campaign period.…”

Section: Diurnal Patternsmentioning

confidence: 99%

“…Southern India nominally experiences two monsoon seasons, the southwest (SW) monsoon and the northeast monsoon (NE; November-January), which are strongly associated with the movement of the Inter-Tropical Convergence Zone, the ITCZ (Kanawade et al, 2014). The SW monsoon winds bring relatively clean marine influx over the continent from the Arabian Sea when the ITCZ moves northwards, reaching 30 • N during July (Naja and Lal, 2002).…”

Section: General Meteorologymentioning

confidence: 99%

Fluorescent biological aerosol particle measurements at a tropical high-altitude site in southern India during the southwest monsoon season

Valsan

Ravikrishna

Biju³

et al. 2016

Atmos. Chem. Phys.

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Abstract. An ultraviolet aerodynamic particle sizer (UV-APS) was continuously operated for the first time during two seasons to sample the contrasting winds during monsoon and winter to characterize the properties of fluorescent biological aerosol particles (FBAPs), at a high-altitude site in India. Averaged over the entire monsoon campaign (1 June–21 August 2014), the arithmetic mean number and mass concentrations of coarse-mode (> 1 µm) FBAPs were 0.02 cm−3 and 0.24 µg m−3, respectively, which corresponded to ∼  2 and 6 % of total aerosol loading, respectively. Average FBAP number size distribution exhibited a peak at ∼  3 µm, which is attributed to the fungal spores, as supported by scanning electron microscope (SEM) images, and these results are consistent with previous studies made for FBAPs. During 11 weeks of measurements the variability of the total coarse-mode particle number (TAP) concentration was high compared to that observed in FBAP number concentrations. The TAP and FBAP number concentrations measured at this site were strongly dependent on changes in wind direction and rainfall. During periods of westerly/southwesterly winds with heavy persistent rainfall, the TAP and FBAP concentrations exhibited very low values (1.3 and 0.005 cm−3, respectively) with no significant diurnal variations, whereas during periods of northerly winds with scattered rainfall FBAPs exhibited relatively high concentration values (0.05 cm−3) with pronounced diurnal variations, which were strongly coupled with diurnal variations in meteorological parameters. The campaign-averaged FBAP number concentrations were shown to correlate with daily patterns of meteorological parameters and were positively correlated with relative humidity (RH; R2  =  0.58) and negatively with temperature (R2  =  0.60) and wind speed (R2  =  0.60). We did not observe any significant positive correlation with precipitation as reported by previous researchers from selected areas. These measurement results confirm the fact that the ratio of PBAPs to TAP is strongly dependent on particle size and location and thus may constitute a significant proportion of total aerosol particles.

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“…However, studies in tropical regions are still very limited (Betha et al, 2013;Iida et al, 2008;Kanawade et al, 2014;Siingh et al, 2013), where the climatic conditions are much different. In particular, over the Indian subcontinent, the systematic analysis for NPF are limited to only a few locations; New Delhi (M€ onkk€ onen et al, 2005), Pune (Siingh et al, 2013), Gual Pahari (Hyv€ arinen et al, 2010), Gadanki (Kanawade et al, 2014), Kullu-Manali in the Western Himalaya , Mukteshwar (Komppula et al, 2009;Neitola et al, 2011), and Hanle in the TransHimalayas (Moorthy et al, 2011). Therefore, we measured particle size distributions in the diameter range of 4e135 nm at Pune during AprileMay 2012.…”

Section: Introductionmentioning

confidence: 98%