Ultrafine particle emission from floor cleaning products

The new particle formation due to the use of cleaning products containing volatile organic compounds (VOCs) in indoor environments is well documented in the scientific literature. Indeed, the physical-chemical process occurring in particle nucleation due to VOC-ozone reactions was deepened as well as the effect of the main influencing parameters (ie, temperature, ozone). Nonetheless, proper quantification of the emission under actual meteo-climatic conditions and ozone concentrations is not available. To this end, in the present paper the emission factors of newly generated ultrafine particles due to the use of different floor cleaning products under actual temperature and relative humidity conditions and ozone concentrations typical of the summer periods were evaluated. Tests in a chamber and in an actual indoor environment were performed measuring continuously particle number concentrations and size distributions during cleaning activities. The tests revealed that a significant particle emission in the nucleation mode was present for half of the products under investigation with emission factors up to 1.1 × 10¹¹ part./m² (8.8 × 10¹⁰ part./mL_product), then leading to an overall particle emission comparable to other well-known indoor sources when cleaning wide surfaces.     

Crime and social sanction*

In this paper we provide evidence that social sanctions represent a very strong deterrent of property crime. We present a formal model relating crime and social sanction to social interaction density. Consistently with our theoretical framework and the literature on network closure and social interactions, we resort to demographic and geomorphological information to develop an exogenous and reliable measure for the density of social interactions based on town dimension and isolation. We estimate a spatial panel model by means of a GMM procedure and we find that areas with denser social interactions display significantly and substantially lower rates of property crime. Resumen. En este artículo aportamos pruebas de que las sanciones sociales constituyen un elemento disuasorio muy poderoso para el crimen contra la propiedad. Presentamos un modelo formal que relaciona el crimen y la sanción social con la densidad de interacción social. De manera consecuente con nuestro marco teórico y la literatura sobre exclusión de redes e interacciones sociales, acudimos a información demográfica y geomorfológica para desarrollar una medida exógena y fiable de la densidad de las interacciones sociales, basada en el tamaño y aislamiento de la ciudad. Estimamos un modelo de panel espacial por medio de un procedimiento de método generalizado de momentos (MGM) y hallamos que las áreas con interacciones sociales más densas muestran significativa y substancialmente tasas menores en crímenes contra la propiedad.