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Thirty-six pre-university chemistry students and two chemistry teachers used flow chemistry as a technology for the synthesis of methyl orange. FutureChemistry and VU University Amsterdam cooperatively created FlowStart Remote, a device that enabled the students to remotely conduct this synthesis and in real time monitor and control the device via a LabVIEW Web application. The students were able to conduct experiments under different conditions and became acquainted with flow chemistry in a safe way. The remotely controlled device can be shared among several upper-level secondary schools, giving access to experimentation for many students all over the world. (Contains 5 figures and 1 scheme.)

The recently developed time of flight-aerosol chemical speciation monitor with the capture vaporizer and a PM2.5 aerodynamic lens (TOF-ACSM-CV-PM2.5) aims to improve the collection efficiency and chemical characterization of aerosol particles with diameter smaller than 2.5µm. In this study, comprehensive cross-comparisons were performed between real-time online measurements and offline filter analysis with 24-hour collection time. The goal was to evaluate the capabilities of the TOFACSM-CV-PM2.5 lens, as well as the accuracy of the TOF-ACSM-CV-PM2.5. The experiments were conducted at Cabauw Experimental Site for Atmospheric Research (CESAR) during the RITA-2021 campaign. The non-refractory fine particulate matter PM1.0 and PM2.5 were measured by two co-located TOF-ACSM-CV-PM2.5 by placing them behind a PM2.5 and PM1.0 inlet, respectively. A comparison between the ACSMs and PM2.5 and PM1.0 filter samples showed a much better accuracy than ±30% less given in the previous reports, with average differences less than ± 10% for all inorganic chemical species. In addition, the ACSMs were compared to a Monitoring Instrument for Aerosol and Gas (MARGA) (slope between 0.78 - 0.97 for inorganic compounds, R2 = 0.93), and a Mobility Particle Size Spectrometer (MPSS) measuring the particle size distribution from around 10 to 800 nm (slope was around 1.00, R2 = 0.91). The intercomparison of the online measurements and the comparison between the online and offline measurements indicated a low bias (< 10% for inorganic compounds) and demonstrated the high accuracy and stability of the TOF-ACSM-CV-PM2.5 lens for the atmospheric observations of particle matters. The two ACSMs exhibited an excellent agreement, with differences less than 7%, which allowed a quantitative estimate of PM1.0 vs PM2.5 chemical composition. The result showed that the PM1.0 accounted for about 70-80% of the PM2.5 on average. The NO3 mass fraction increased but the OC mass fraction decreased from PM1.0 to PM2.5, indicating the size30 dependence on chemical composition. [ABSTRACT FROM AUTHOR]

The recently developed time of flight-aerosol chemical speciation monitor with the capture vaporizer and a PM2.5 aerodynamic lens (TOF-ACSM-CV-PM2.5) aims to improve the collection efficiency and chemical characterization of aerosol particles with a diameter smaller than 2.5 µm. In this study, comprehensive cross-comparisons were performed between real-time online measurements and offline filter analysis with 24-hour collection time. The goal was to evaluate the capabilities of the TOF-ACSM-CV-PM2.5 lens, as well as the accuracy of the TOF-ACSM-CV-PM2.5. The experiments were conducted at Cabauw Experimental Site for Atmospheric Research (CESAR) during the RITA-2021 campaign. The non-refractory fine particulate matter PM1.0 and PM2.5 were measured by two co-located TOF-ACSM-CV-PM2.5 by placing them behind a PM2.5 and PM1.0 inlet, respectively. A comparison between the ACSMs and PM2.5 and PM1.0 filter samples showed a much better accuracy than ±30 % less given in the previous reports, with average differences less than ± 10 % for all inorganic chemical species. In addition, the ACSMs were compared to a Monitoring Instrument for Aerosol and Gas (MARGA) (slope between 0.78–0.97 for inorganic compounds, R2 ≥ 0.93), and a Mobility Particle Size Spectrometer (MPSS) measuring the particle size distribution from around 10 to 800 nm (slope was around 1.00, R2 = 0.91). The intercomparison of the online measurements and the comparison between the online and offline measurements indicated a low bias (< 10 % for inorganic compounds) and demonstrated the high accuracy and stability of the TOF-ACSM-CV-PM2.5 lens for the atmospheric observations of particle matters. The two ACSMs exhibited an excellent agreement, with differences less than 7 %, which allowed a quantitative estimate of PM1.0 vs PM2.5 chemical composition. The result showed that the PM1.0 accounted for about 70–80 % of the PM2.5 on average. The NO3 mass fraction increased but the OC mass fraction decreased from PM1.0 to PM2.5, indicating the size-dependence on chemical composition. [ABSTRACT FROM AUTHOR]

Elevated nitrogen (N) deposition and changes in reduced or oxidized component contribution greatly affect soil acidification. China has experienced a significant transformation of N deposition components from NHx to NOy over the past 40 years, but the effects of component transformation on soil acidification are poorly understood. Therefore, long‐term monitoring data and literature on N deposition, combined with the results of isotope experiments, were used to explore the contributions of different N forms on soil acidification in China's forests. Here, all processes related to NHx and NOy, including the transformation to NH4+ and NO3− and subsequent N cycling in the soil, were considered. We found that N‐induced soil acidification in 80% area of China's forests was dominated by NHx deposition, and the other areas (South China) were dominated by NOy deposition in 2010s. From 1980 to 2019, the average contribution of NHx was higher than that of NOy but the latter contribution continued to increase. Meanwhile, the results showed that soil acidification increased with the decrease of the ratio of NHx to NOy (RNHx/NOy), which is mainly because NOy is more easily leached in the form of NO3− than that of NHx under the influence of different plant preferences and soil retention rates, resulting in a higher net proton production of NOy. Our research has powerful implications for policymaking, provides a theoretical basis for formulating different N reduction policies in different regions, and points out that the synergistic effect of RNHx/NOy changes should be considered to alleviate soil acidification. Key Points: Most forest soil was dominated by the contribution of NHx deposition, causing soil acidificationThe contribution of NOy deposition to soil acidification increased continuously during 1980–2019Decreased ratio of NHx to NOy deposition has led to aggravated forest soil acidification [ABSTRACT FROM AUTHOR]