Chemistry of new particle growth in mixed urban and biogenic emissions - Insights from CARES

Regional new particle formation and growth events (NPEs) were observed on most days over the Sacramento and western Sierra foothills area of California in June 2010 during the Carbonaceous Aerosols and Radiative Effect Study (CARES). Simultaneous particle measurements at both the T0 (Sacramento, urban site) and the T1 (Cool, rural site located ~40 km northeast of Sacramento) sites of CARES indicate that the NPEs usually occurred in the morning with the appearance of an ultrafine mode at ~15 nm (in mobility diameter, Dm, measured by a mobility particle size spectrometer operating in the range 10-858 nm) followed by the growth of this modal diameter to ~50 nm in the afternoon. These events were generally associated with southwesterly winds bringing urban plumes from Sacramento to the T1 site. The growth rate was on average higher at T0 (7.1 ± 2.7 nm h−1) than at T1 (6.2 ± 2.5 nm h−1), likely due to stronger anthropogenic influences at T0. Using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), we investigated the evolution of the size-resolved chemical composition of new particles at T1. Our results indicate that the growth of new particles was driven primarily by the condensation of oxygenated organic species and, to a lesser extent, ammonium sulfate. New particles appear to be fully neutralized during growth, consistent with high NH3 concentration in the region. Nitrogen-containing organic ions (i.e., CHN+, CH4N+, C2H3N+, and C2H4N+) that are indicative of the presence of alkyl-amine species in submicrometer particles enhanced significantly during the NPE days, suggesting that amines might have played a role in these events. Our results also indicate that the bulk composition of the ultrafine mode organics during NPEs was very similar to that of anthropogenically influenced secondary organic aerosol (SOA) observed in transported urban plumes. In addition, the concentrations of species representative of urban emissions (e.g., black carbon, CO, NOx, and toluene) were significantly higher whereas the photo-oxidation products of biogenic VOCs (volatile organic compounds) and the biogenically influenced SOA also increased moderately during the NPE days compared to the non-event days. These results indicate that the frequently occurring NPEs over the Sacramento and Sierra Nevada regions were mainly driven by urban plumes from Sacramento and the San Francisco Bay Area, and that the interaction of regional biogenic emissions with the urban plumes has enhanced the new particle growth. This finding has important implications for quantifying the climate impacts of NPEs on global scale

The Body Dances: Carnival Dance and Organization

Building on the work of Pierre Bourdieu and Maurice Merleau-Ponty we seek to open up traditional categories of thought surrounding the relation `body-organization' and elicit a thought experiment: What happens if we move the body from the periphery to the centre? We pass the interlocking theoretical concepts of object-body/subject-body and habitus through the theoretically constructed empirical case of `carnival dance' in order to re-evaluate such key organizational concepts as knowledge and learning. In doing so, we connect with an emerging body of literature on `sensible knowledge'; knowledge that is produced and preserved within bodily practices. The investigation of habitual appropriation in carnival dance also allows us to make links between repetition and experimentation, and reflect on the mechanism through which the principles of social organization, whilst internalized and experienced as natural, are embodied so that humans are capable of spontaneously generating an infinite array of appropriate actions. This perspective on social and organizational life, where change and permanence are intricately interwoven, contrasts sharply with the dominant view in organization studies which juxtaposes change/ creativity and stability

Characterization of submicron particles influenced by mixed biogenic and anthropogenic emissions using high-resolution aerosol mass spectrometry: Results from CARES

An Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed during the Carbonaceous Aerosols and Radiative Effects Study (CARES) that took place in northern California in June 2010. We present results obtained at Cool (denoted as the T1 site of the project) in the foothills of the Sierra Nevada Mountains, where intense biogenic emissions are periodically mixed with urban outflow transported by daytime southwesterly winds from the Sacramento metropolitan area. During this study, the average mass loading of submicrometer particles (PM1) was 3.0 μg m−3, dominated by organics (80%) and sulfate (9.9%). The organic aerosol (OA) had a nominal formula of C1H1.38N0.004OM0.44, thus an average organic mass-to-carbon (OM/OC) ratio of 1.70. Two distinct oxygenated OA factors were identified via Positive matrix factorization (PMF) of the high-resolution mass spectra of organics. The more oxidized MO-OOA (O/C = 0.54) was interpreted as a surrogate for secondary OA (SOA) influenced by biogenic emissions whereas the less oxidized LO-OOA (O/C = 0.42) was found to represent SOA formed in photochemically processed urban emissions. LO-OOA correlated strongly with ozone and MO-OOA correlated well with two 1st generation isoprene oxidation products (methacrolein and methyl vinyl ketone), indicating that both SOAs were relatively fresh. A hydrocarbon like OA (HOA) factor was also identified, representing primary emissions mainly due to local traffic. On average, SOA (= MO-OOA + LO-OOA) accounted for 91% of the total OA mass and 72% of the PM1 mass observed at Cool. Twenty three periods of urban plumes from T0 (Sacramento) to T1 (Cool) were identified using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). The average PM1 mass loading was considerably higher in urban plumes than in air masses dominated by biogenic SOA. The change in OA mass relative to CO (ΔOA/ΔCO) varied in the range of 5-196 μg m−3 ppm−1, reflecting large variability in SOA production. The highest ΔOA/ΔCO was reached when air masses were dominated by anthropogenic emissions in the presence of a high concentration of biogenic volatile organic compounds (BVOCs). This ratio, which was 97 μg m−3 ppm−1 on average, was much higher than when urban plumes arrived in a low BVOC environment (~36 μg m−3 ppm−1) or during other periods dominated by biogenic SOA (35 μg m−3 ppm−1). These results demonstrate that SOA formation is enhanced when anthropogenic emissions interact with biogenic precursors

Search and Liquidity in Single-Family Housing

A two-stage least squares model of housing prices is estimated with data collected from 3358 single-family home transactions. The results provide evidence for an optimal marketing period and indicate that a liquidity premium is priced in single-family home sales. Consistent with the hypothesis derived from economic search models, the model shows higher selling prices for houses having longer expected marketing periods. The model also shows a price premium for houses that sell faster than expectations. This effect supports the concept that liquidity is a value-enhancing characteristic. Copyright American Real Estate and Urban Economics Association.

Biology's gift: interrogating the turn to affect

This article investigates how the turn to affect within the humanities and social sciences re-imagines the relationship between cultural theory and science. We focus on how the writings of two neuroscientists (Antonio Damasio and Joseph LeDoux) and one developmental psychologist (Daniel Stern) are used in order to ground certain claims about affect within cultural theory. We examine the motifs at play in cultural theories of affect, the models of (neuro)biology with which they work, and some fascinating missteps characterizing the taking up of scientific literature. While neuroscience frames the affective as part of a system of regulation that makes both self and social coherence possible, in cultural theory’s narratives, by contrast, affectivity becomes a placeholder for the inherent dynamism and mutability of matter. The article interrogates the consequences of cultural theory’s strange borrowings from neuroscience and developmental psychology in their institution of a model of subjectivity preoccupied with a lived present in excess of the hold of habit and embodied history

Knowing the ‘Going’: the sensory evaluation of distance running

To date there has been little research into the mundane direct embodiment of sporting activity. This paper seeks to contribute to a small but developing literature by portraying how distance running training sessions are experienced in a sensory way and how that direct embodied knowledge is used to categorise and evaluate the practise of ongoing training. The paper looks at the sensory practices which are used to evaluate distance running performanc