Aerosols from biomass burning can alter the radiative balance of the Earth by reflecting and absorbing solar radiation1. Whether aerosols exert a net cooling or a net warming effect will depend on the aerosol type and the albedo of the underlying surface2. Here, we use a satellite-based approach to quantify the direct, top-of-atmosphere radiative effect of aerosol layers advected over the partl...

Infrared extinction spectra in the 3-5-microm and 7-13-microm atmospheric window regions have been obtained for smokes of petroleum oil, sulfuric acid, and phosphoric acid of varying droplet concentration and for water fogs. Spectra were also obtained at 0.36-2.35microm for petroleum oil and sulfuric acid smokes. Experimental results were compared, for sulfuric acid and water aerosols, to calcu...

The effect of aerosols on 14 tropospheric photolysis reactions is examined under noncloudy and cloudy sky conditions by using a detailed one-dimensional radiative transfer model. Pure (NH4)2SO4, pure soot, and internal and external mixtures of the two aerosols, as well as mineral dust aerosol, are considered. Nonabsorbing aerosol generally enhances photolysis rates above and in the upper part o...

Global distribution of aeolian dust is simulated from 1981 to 1996 with the Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model. The results are compared with in situ measurements and satellite data. An index is calculated from the model results and the satellite viewing angles to allow quantitative comparison with the Total ozone mapping spectrometer (TOMS) absorbing aerosol ...

[1] The processes that determine which areas are strong sources of mineral aerosols are not well known. In this study we consider the role of ephemeral lakes in modulating emissions of atmospheric mineral aerosols. We focus on two ephemeral lake regions that have been identified as source regions: the zone of Chotts in Tunisia and Algeria, and Etosha Pan in Namibia. Comparisons of satellite ret...

AbstractThere is considerable interest in identifying new antioxidants from plant materials. Several studies have emphasized the antioxidant activity of species belonging to the Myrtaceae family. However, there are few reports on these species from the Cerrado (Brazilian savanna). In this study, the antioxidant activity and phenolic content of 12 native Myrtaceae species from the Cerrado were e...

OBJECTIVES The present study was designed to examine the associations of coronary calcification assessed by electron beam computed tomography (CT) with measures of extracoronary atherosclerosis. BACKGROUND Although measures of extracoronary atherosclerosis have been used to predict coronary events, it is not yet known to what extent those measures reflect coronary atherosclerosis. METHODS The R...

Abstract. We evaluate the sensitivity of size calibrations two commercially available, high-resolution optical particle sizers to changes in aerosol composition and complex refractive index (RI). The Droplet Measurement Technologies Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) TSI, Inc. Laser (LAS) are commonly used instruments for measuring portion distribution with diameters larger tha...