Peak exposure concentrations of dust and flour aeroallergen in flour mills and bakeries.

As part of an epidemiological study amongst workers exposed to flour we measured peak exposure levels to total dust and flour aeroallergen with personal samplers in bakeries, flour mills and packing stations. Short-term tasks which were expected to give rise to high concentrations of exposure (peaks) were identified. The frequency and duration of these tasks were estimated and their levels of exposure to dust and flour aeroallergen measured. In total 209 samples were taken. The highest exposure concentrations both for dust (geometric mean > 30 mg m-3) and for flour aeroallergen (geometric mean > 500 micrograms m-3) were measured during certain operations. Exposure concentrations for the tasks were often much higher than the levels we had measured over a shift in a previous study. This might be important for sensitization and for the development of asthma. Peak exposure concentrations could be used to explore the exposure-response relationship more comprehensively. In general average flour aeroallergen concentrations increased linearly with average dust concentrations, although there were some exceptions

Dust and flour aeroallergen exposure in flour mills and bakeries.

As part of an epidemiological study among workers exposed to flour total dust and flour aeroallergen concentrations were measured with personal samplers over a workshift in three large bakeries and four flour mills and packing stations. In the bakeries geometric means for total dust concentrations ranged from 0.4 mg/m3 in the bread wrapping area up to 6.4 mg/m3 at the dough brake. The flour aeroallergen concentrations ranged from 45.5 micrograms/m3 in the bread wrapping area up to 252.0 micrograms/m3 in the confectionary area. In the flour mills and packing stations the concentrations were higher with geometric means for total dust ranging from 0.5 mg/m3 in the office up to 16.9 mg/m3 for hygiene workers in an old mill. The flour aeroallergen concentrations ranged from 101.5 micrograms/m3 for transport workers up to 1728.2 micrograms/m3 for hygiene workers. The relation between total dust and flour aeroallergen concentrations varied for different areas and depended on the use of products other than flour

Geomorphology reveals active decollement geometry in the central Himalayan seismic gap

The similar to 700-km-long ``central seismic gap'' is the most prominent segment of the Himalayan front not to have ruptured in a major earthquake during the last 200-500 yr. This prolonged seismic quiescence has led to the proposition that this region, with a population >10 million, is overdue for a great earthquake. Despite the region's recognized seismic risk, the geometry of faults likely to host large earthquakes remains poorly understood. Here, we place new constraints on the spatial distribution of rock uplift within the western similar to 400 km of the central seismic gap using topographic and river profile analyses together with basinwide erosion rate estimates from cosmogenic Be-10. The data sets show a distinctive physiographic transition at the base of the high Himalaya in the state of Uttarakhand, India, characterized by abrupt strike-normal increases in channel steepness and a tenfold increase in erosion rates. When combined with previously published geophysical imaging and seismicity data sets, we interpret the observed spatial distribution of erosion rates and channel steepness to reflect the landscape response to spatially variable rock uplift due to a structurally coherent ramp-flat system of the Main Himalayan Thrust. Although it remains unresolved whether the kinematics of the Main Himalayan Thrust ramp involve an emergent fault or duplex, the landscape and erosion rate patterns suggest that the decollement beneath the state of Uttarakhand provides a sufficiently large and coherent fault segment capable of hosting a great earthquake