Observing super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate at an agro-forest site in Thailand.

Coarse aerosol particles containing chloride in tropical forests are significant for understanding biogeochemical cycles and atmospheric processes, with implications for environmental health and climate change mitigation. This study explored the sources of super-coarse carbonaceous aerosol particles containing chloride in a tropical savanna climate. Aerosol samples were collected from an agro-forest site in Thailand during the dry season and analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy.

The perception of air pollution and its health risk: a scoping review of measures and methods.

Background: Although there is increasing awareness of the health risks of air pollution as a global issue, few studies have focused on the methods for assessing individuals' perceptions of these risks. This scoping review aimed to identify previous research evaluating individuals' perceptions of air pollution and its health effects, and to explore the measurement of perceptions, as a key resource for health behaviour.

Methods: The review followed the methodological framework proposed by Arksey and O'Malley.

Very high particulate pollution over northwest India captured by a high-density in situ sensor network.

Exposure to particulate matter less than 2.5 µm in diameter (PM) is a cause of concern in cities and major emission regions of northern India. An intensive field campaign involving the states of Punjab, Haryana and Delhi national capital region (NCR) was conducted in 2022 using 29 Compact and Useful PM Instrument with Gas sensors (CUPI-Gs).

Potential Factors Contributing to Ozone Production in AQUAS-Kyoto Campaign in Summer 2020: Natural Source-Related Missing OH Reactivity and Heterogeneous HO/RO Loss.

This study presents total OH reactivity, ancillary trace species, HO reactivity, and complex isoprene-derived RO reactivity due to ambient aerosols measured during the air quality study (AQUAS)-Kyoto campaign in September, 2020. Observations were conducted during the coronavirus disease (COVID-19) pandemic (associated with reduced anthropogenic emissions). The spatial distribution of missing OH reactivity highlights that the origin of volatile organic compounds (VOCs) may be from natural-emission areas.

Total hydroxyl radical reactivity measurements in a suburban area during AQUAS-Tsukuba campaign in summer 2017.

Missing hydroxyl radical (OH) reactivity from unknown/unmeasured trace species empirically accounts for 10%-30% of total OH reactivity and may cause significant uncertainty regarding estimation of photochemical ozone production. Thus, it is essential to unveil the missing OH reactivity for developing an effective ozone mitigation strategy. In this study, we conducted simultaneous observations of total OH reactivity and 54 reactive trace species in a suburban area as part of the Air QUAlity Study (AQUAS)-Tsukuba campaign for the summer of 2017 to gain in-depth insight into total OH reactivity in an area that experienced relatively high contributions of secondary pollutants.

Relative and Absolute Sensitivity Analysis on Ozone Production in Tsukuba, a City in Japan.

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.

Effect of Oxidation Process on Complex Refractive Index of Secondary Organic Aerosol Generated from Isoprene.

Oxidation of isoprene by hydroxyl radical (OH), ozone (O), or nitrate radical (NO) leads to the formation of secondary organic aerosol (SOA) in the atmosphere. This SOA contributes to the radiation balance by scattering and absorbing solar radiation. In this study, the effect of oxidation processes on the wavelength-dependent complex refractive index (RI) of SOA generated from isoprene was examined.

Continuous measurements of stable isotopes of carbon dioxide and water vapour in an urban atmosphere: isotopic variations associated with meteorological conditions.

Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO and water vapour were observed. The isotope ratios of both CO and water vapour decreased during the typhoon passage.

In situ measurement of CO2 and water vapour isotopic compositions at a forest site using mid-infrared laser absorption spectroscopy.

We conducted continuous, high time-resolution measurements of CO2 and water vapour isotopologues ((16)O(12)C(16)O, (16)O(13)C(16)O and (18)O(12)C(16)O for CO2, and H2(18)O for water vapour) in a red pine forest at the foot of Mt. Fuji for 9 days from the end of July 2010 using in situ absorption laser spectroscopy. The δ(18)O values in water vapour were estimated using the δ(2)H-δ(18)O relationship.

Development of the trigeminal motor neurons in parrots: implications for the role of nervous tissue in the evolution of jaw muscle morphology.

Vertebrates have succeeded to inhabit almost every ecological niche due in large part to the anatomical diversification of their jaw complex. As a component of the feeding apparatus, jaw muscles carry a vital role for determining the mode of feeding. Early patterning of the jaw muscles has been attributed to cranial neural crest-derived mesenchyme, however, much remains to be understood about the role of nonneural crest tissues in the evolution and diversification of jaw muscle morphology.

Molecular and cellular changes associated with the evolution of novel jaw muscles in parrots.

Vertebrates have achieved great evolutionary success due in large part to the anatomical diversification of their jaw complex, which allows them to inhabit almost every ecological niche. While many studies have focused on mechanisms that pattern the jaw skeleton, much remains to be understood about the origins of novelty and diversity in the closely associated musculature. To address this issue, we focused on parrots, which have acquired two anatomically unique jaw muscles: the ethmomandibular and the pseudomasseter.

Fluorescence detection of atmospheric nitrogen dioxide using a blue light-emitting diode as an excitation source.

We report on the development of a low-cost and compact instrument for quantifying atmospheric NO(2) concentrations by detecting NO(2) fluorescence using a commercial light-emitting diode around 435 nm as a fluorescence excitation light source. The minimum detectable limit of the NO(2) instrument developed has been estimated to be 9.8 parts per billion of volume mixing ratio (ppbv) in a 60 s integration time and with a signal-to-noise ratio of 2.

Atmospheric chemistry of BrO radicals: kinetics of the reaction with C2H5O2 radicals at 233-333 K.

Cavity ring-down spectroscopy was used to study the title reaction in 50-200 Torr of O2 diluent at 233-333 K. There was no discernible effect of total pressure, and a rate constant of k(BrO + C2H5O2) = (3.8 +/- 1.

A gas-phase kinetic study of the reaction between bromine monoxide and methylperoxy radicals at atmospheric temperatures.

The rate constant of the reaction of BrO with CH(3)O(2) was determined to be k1 = (6.2 +/- 2.5) x 10(-12) cm3 molecule(-1) s(-1) at 298 K and 100-200 Torr of O2 diluent.

Nitrate radical quantum yield from peroxyacetyl nitrate photolysis.

Peroxyacetyl nitrate (PAN, CH3C(O)OONO2) is a ubiquitous pollutant that is primarily destroyed by either thermal or photochemical mechanisms. We have investigated the photochemical destruction of PAN using a combination of laser pulsed photolysis and cavity ring-down spectroscopic detection of the NO3 photoproduct. We find that the nitrate radical quantum yield from the 289 nm photolysis of PAN is Phi(NO3)PAN = 0.

Atmospheric chemistry of CH3CHF2 (HFC-152a): kinetics, mechanisms, and products of Cl atom- and OH radical-initiated oxidation in the presence and absence of NO(x).

Smog chamber/Fourier transform infrared (FTIR) and laser-induced fluorescence (LIF) spectroscopic techniques were used to study the atmospheric degradation of CH3CHF2. The kinetics and products of the Cl(2P(3/2)) (denoted Cl) atom- and the OH radical-initiated oxidation of CH3CHF2 in 700 Torr of air or N2; diluents at 295 +/- 2 K were studied using smog chamber/FTIR techniques. Relative rate methods were used to measure k(Cl + CH3CHF2) = (2.

N(4S) formation following the 193.3-nm ArF laser irradiation of NO and NO2 and its application to kinetic studies of N(4S) reactions with NO and NO2.

Formation of the ground-state nitrogen atom, N((4)S), following 193.3-nm ArF laser irradiation of NO and NO(2) was detected directly by a technique of laser-induced fluorescence (LIF) spectroscopy at 120.07 nm.