[1] We used laser-induced fluorescence to measure the concentrations of OH and HO 2 radicals in central Tokyo during two intensive campaigns (IMPACT IVand IMPACT L) in January-February and July-August 2004. The estimated detection limit for the 10-min data was 1.3 Â 10 5 cm À3 for the nighttime and 5.2 Â 10 5 cm À3 for the daytime. The median values of the daytime peak concentrations of HO 2 were 1.1 and 5.7 pptv for the winter and summer periods, respectively, while the values for OH were 1.5 Â 10 6 and 6.3 Â 10 6 cm À3 . High HO 2 mixing ratios (>50 pptv) were observed on a day in summer when O 3 mixing ratios exceeded 100 ppbv. The average nighttime concentrations of HO 2 were 0.7 and 2.6 pptv for the winter and summer periods, respectively, while the values for OH were 1.8 Â 10 5 and 3.7 Â 10 5 cm À3 . A photochemical box model constrained by ancillary observations was able to reproduce daytime OH concentrations reasonably well for both periods, although daytime HO 2 concentrations were underestimated in winter and overestimated in summer. Increasing the wintertime hydrocarbon concentrations in the model led to an increase in daytime HO 2 concentrations, thereby showing better agreement with observations; however, the model continued to underestimate HO 2 concentrations at high NO mixing ratios. This underestimate was most pronounced in the mornings of both periods and during the daytime in winter. We studied processes that are capable of explaining this discrepancy, including unknown reactions of HNO 4 or an unidentified HO x source that is linearly scalable to the NO mixing ratio. The important processes in terms of producing radicals were the olefin + O 3 reactions in the nighttime of both periods and during the daytime in winter, the photolysis of carbonyls in the daytime for both periods, and the photolysis of HONO during the daytime in winter (using measured HONO concentrations) and during mornings in summer (using estimated HONO concentrations).

[1] We used laser-induced fluorescence to measure concentrations of OH and HO 2 at Rishiri Island, Japan, during September 2003. The average maximum daytime concentrations were 2.7 Â 10 6 cm À3 for OH and 5.9 pptv for HO 2 . The observed concentrations were compared to those predicted by a photochemical box model constrained by ancillary observations. During the daytime, the model overestimated HO 2 levels by an average of 89% and OH levels by an average of 35%. This overestimate of OH was rectified when the model was constrained by observed HO 2 levels, suggesting that loss processes of HO 2 were missing in the model. We calculated the loss rates of HO 2 required to bring the modeled HO 2 levels into agreement with observed levels. We then studied processes that are capable of explaining the loss rates, including halogen chemistry, heterogeneous loss of HO 2 on aerosol surfaces, and the possibility of more rapid HO 2 + RO 2 reactions than expected. In the nighttime, most of the observed hourly averaged OH and 10-min-averaged HO 2 concentrations were statistically significant and fell in the ranges (0.7-5.5) Â 10 5 cm À3 and 0.5-4.9 pptv, respectively. Both HO 2 and OH concentrations showed strong positive correlations with total monoterpene concentrations, strongly suggesting that the radicals were produced via reactions of monoterpenes. The median nighttime modeled-to-observed ratios were 1.29 and 0.56 for HO 2 and OH, respectively. These ratios dropped to 0.49 and 0.29 during the evening of 25 September, possibly related to the presence of unmeasured olefinic species or chemical reactions involving RO 2 that are poorly represented in the model.

Pollutant emissions from indoor cooking activities using clean fuels such as natural gas or LPG are strongly influenced by cooking ingredients and cooking methods. In this study, we explore the characterization of indoor fine particles (PM 2.5 ) and CO that are produced by two distinctive cooking methods: frying and boiling. This characterization includes quantifying the presence of fine particles in a kitchen as well as in the adjoining room, analyzing size-segregated carbonaceous materials (EC and OC), and identifying variations in CO associated with the cooking method. Four monitoring devices-a UCB particle monitor, an optical particle counter, a cascade impactor, and a CO monitor-were simultaneously used to measure temporal variations in mass concentrations of fine particles (PM 2.5 ), particle number concentrations, their size distributions, and CO concentrations in the two rooms, respectively. EC and OC analyses of the particles collected on a quartz filter by cascade impactor were conducted using the thermal optical method. Frying produced higher emissions of fine particles with a wider range of aerodynamic sizes than boiling. Particle spatial distribution was uniform across the rooms during boiling, because emissions were dominated by very fine particle size. It was observed that particle mass size distributions with cut size ≤ 0.25 µm were predominant in all cooking methods. CO concentration was lowest in tofu boiling and about one-tenth of the stove background level. This is possibly due to the absorption of CO by steam cooking.

In order to remove fog often causes various troubles in our daily lives, the novel defog blower equipped the roller brush made of recycled horse's mane hair was developed. This work presents the overview of new defog devices and the experimental data obtain ed at two different kinds of defogging experiments. In the model experiment carried out at the enclosed cleanroom (W 5.9 m × L 5.1 m × H 2.4 m) targeted a vinyl house, fog was dissipated in less than 30 sec onds in case with wind entrainment and two minutes 45 seconds in case without wind entrainment after running of the newly designed defog blower. When the demisting blower was run in a duct, it has an excellent mist sweeping qualities as well as a great removal effect for the background particles (89.5% and 65.4% scavenging rates for fine and coarse par ticles, respectively). It can be therefore said that the mist eliminator presented in this paper is ideal for use in the sealing space like a vinyl house and the industrial sites where required to remove both harmful mist and particle.