Search

The methods of sampling, carrying and keeping, and the instruments for measuring atmospheric peroxyacetyl nitrate (PAN) and peroxypropionyl nitrate (PPN), were developed for field studies and had been used for the surveys on four remote islands and in the troposphere since 1991. PAN and PPN were detected in most of over 500 samples. Mean concentrations of PAN and PPN in the islands and in the lower troposphere(altitude; 400-4500 m) from the Yellow Sea to the Japan Sea are 0.1-0.4 ppb (10-9, v/v) and 0.01-0.03 ppb, respectively. Good correlation between PAN and PPN at each point was observed, and PPN was found to be 5-9% of PAN. In addition, PAN in the urban area had been monitored continuously at Ichihara close to metropolitan Tokyo since 1985. The yearly means of PAN there were constantly around 0.4 ppbfor ten years. The ratios of PANs to NOx* or NOx+ (which were detected by chemiluminescence type or Griess-Saltzman type of NOx analyzers) were found to be mostly, 1% in the urban air, 15-20% on the remote islands, and 15-60% in the lower troposphere (occasionally exceed 80% in the upper 2500 m altitude). PANs in the remote area were confirmed to be relatively more important, compared with in the urban area. The higher ratios in aircraft surveys were partly related to the atmospheric temperature in the sampling area. [ABSTRACT FROM AUTHOR]

Potency tests for influenza vaccines are currently performed using a single-radial immunodiffusion (SRID) assay, which requires a reference antigen and anti-hemagglutinin (HA) serum as reference reagents. Reagents must be newly prepared each time a strain used for vaccine production is modified. Therefore, establishing reference reagents of consistent quality is crucial for conducting vaccine potency tests accurately and precisely. Here, we established reference reagents for the SRID assay to conduct lot release tests of quadrivalent influenza vaccines in Japan during the 2022/23 influenza season. The potency of reference antigens during storage was confirmed. Furthermore, we evaluated the cross-reactivity of each antiserum raised against the HA protein of the 2 lineages of influenza B virus toward different lineages of influenza B virus antigens to select a suitable procedure for the SRID assay for accurate measurement. Finally, the intralaboratory reproducibility of the SRID assay using the established reference reagents was validated, and the SRID reagents had sufficient consistent quality, comparable to that of the reagents used for testing vaccines during previous influenza seasons. Our study contributes to the quality control of influenza vaccines.

The heterogeneous loss of HO 2 radicals onto ambient aerosols plays an important role in tropospheric chemistry. However, sparse investigation of the dominating parameters controlling the HO 2 uptake coefficients onto ambient aerosols (γHO 2 ) has largely hindered the application of the measured γHO 2 to the global spatial prediction. Here we induced an offline method using LFP-LIF technique to measure the kinetics of HO 2 uptake onto ambient aerosols collected in summertime and wintertime in Yokohama city, a regional urban site near Tokyo, Japan. By controlling the dominating parameters which influence γHO 2 , we were able to investigate the detailed HO 2 uptake mechanism. We characterized the chemical composition of the collected ambient aerosols, including organics, inorganics, transition metals ions, etc. and modeled γHO 2 using different mechanisms. Results show that γHO 2 increased with the increase in RH, and the aerosol states ("dry" or wet/aqueous) have large effects on γHO 2 . With fixed RH and aerosol chemical composition, γHO 2 was highly dependent on pH and inversely correlated with [HO 2 ] 0 . By combing the measured γHO 2 values with the modeled ones, we found that both the HO 2 self-reaction and transition metal-catalyzed reactions should be accounted for to yield a single parameterization to predict γHO 2 , and different chemical compositions may have collective effects on γHO 2 . Results may serve for extending the γHO 2 values measured at one observation site to different environmental conditions, which will help us to achieve more accurate modeling results concerning secondary pollutant formation (i.e., ozone)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The change in the ozone production rate on reducing its precursors, namely, ozone production sensitivity, is important information for developing a strategy to reduce ozone. We expanded a conventional sensitivity analysis theory by including peroxy radical loss by uptake onto particle surfaces in the aim of examining their potential impact. We also propose a new concept of absolute sensitivity that enables us to evaluate the quantitative effectiveness of precursor reduction toward mitigating ozone production over a given period and area. This study applies the theory to observations in Tsukuba, a city in Japan. The relative sensitivity analysis shows that ozone production was more sensitive to volatile organic compounds (VOCs) in the morning and evening, and it became more sensitive to NO x in the afternoon. NO depletion was a main trigger in this sensitivity regime transition. The absolute sensitivity analysis indicates that the VOC-sensitive period in the morning determines the total ozone production sensitivity in a day. While particles did not have significant impact on regime classification in Tsukuba, they have a potential to decrease the mitigating effect of VOC reduction on ozone production and to moderate the enhancement effect of NO x reduction depending upon uptake coefficients. A further study will benefit from a combination with an observation-constrained box model simulation or chemical transport modeling system, which may provide sensitivity analysis over a large spatial and temporal range.

An intensive field survey, with 6-h measurement intervals, of concentrations of chemical species in particulate matter and gaseous compounds was carried out at coastal sites on the Sea of Japan during winter. The concentration variation of SO(2)(g) and HNO(3)(g) were well correlated, whereas the NH(3)(g) concentration variation had no correlation with those of SO(2)(g) and HNO(3)(g). The NH(4) (+) (p)/non-sea-salt- (nss-)SO(4) (2 -)(p) ratio in particulate matter was mainly affected by the location of the sampling site. One or more concentration peaks of nss-Ca(2 +) for survey period were observed. Backward trajectories analyses for the highest nss-Ca(2 +) concentration peaks showed some inconsistency in pathways. We consider that insufficient mixing of the atmosphere and/or insufficient time for the transported air pollutants to react with those discharged locally are the most likely explanations for the discrepancies between the measured products [HNO(3)][NH(3)] and the calculated values.