The correlation of atmospheric pollution by VOC and NMHC/NOX ratio has been found. By usingNMHC/NOX ratio, the source of NMHC in the region can be presumed without effects from the diffusionand the dilution by the meteorological conditions. At general measurement station in A city OsakaPrefecture, the NMHC/NOX ratio shows high value in summer though NMHC and NOX concentrationshow high value in early winter. As opposed to city A, traffic measurement station C doesnt show thispattern. It suggests that the amount of the exhaust of NMHC increases along with the temperature.
As part of a larger indoor environmental study, residential indoor and outdoor levels ofnitrogen dioxide (NO2) were measured for 14 houses in a suburb of Brisbane, Queensland,Australia. Passive samplers were used for 48-h sampling periods during the winter of 1999.The average indoor and outdoor NO2 levels were 13.8 6.3 and 16.7 4.2 ppb, respectively.The indoor/outdoor NO2 concentration ratio ranged from 0.4 to 2.3, with a median value of0.82.
A children's day care centre in Finland was the site of a study on the effect of ventilation and air filtration systems on indoor air quality. Indoor and outdoor concentrations of NO, NO2, TSP and PM10 were measured using automatic nitrogen oxide analysers and dust monitoring. Nitrogen oxides and particulate matter from traffic penetrated easily in the absence of filters.50%-70% of nitrogen oxides were excluded with chemical filtration. At holidays and weekends, the particle levels fell less than 10% of the outdoor level, rising to 25% on weekdays.
In this study we evaluated the diffusion of nitrous oxide in a few operating rooms, using spatial data modelling techniques, in order to assess hospital staff exposure and to promote risk management. Indoor air sampling was carried out, during routine operating activity, by means of transportable infrared spectrometer, with geostatistical techniques. We detected high average concentrations of nitrous oxide (from 8 ppm to 445 ppm, with a peak of 1345 ppm).