Noise monitor 2016 : Validation of motorway and railway noise

Geluidniveaus gemeten op 38 punten langs rijkswegen lagen in 2015 gemiddeld 2 decibel hoger dan de berekende waarden. Op 39 meetlocaties langs het spoor kwamen de gemeten en berekende geluidniveaus in 2015 gemiddeld met elkaar overeen. Dit beeld stemt overeen met de voorgaande jaren 2013 en 2014. Op de afzonderlijke punten, zowel bij rijkswegen als het spoor, variëren verschillen ten opzichte van het gemiddelde. Bij de weg liggen de metingen tussen 2 decibel lager en 6 decibel hoger dan de berekende waarden, afhankelijk van het type en de lokale staat van het wegdek. De vergelijking van metingen met berekeningen is een verplichting uit de Wet milieubeheer. De weg- en spoorbeheerder, Rijkswaterstaat en ProRail, tonen via berekening aan of het geluid van de weg of het spoor onder de vastgestelde geluidproductieplafonds blijft. De berekende geluidniveaus worden jaarlijks door het RIVM gevalideerd met een steekproef van metingen. Dit rapport geeft ook de meetresultaten uit 2016 op 45 locaties langs de weg en 40 locaties langs het spoor. De meetresultaten uit 2016 zullen in een vervolgrapportage worden vergeleken met de rekenresultaten. De weg- en spoorbeheerder publiceren deze in de tweede helft van 2017.Noise levels measured at 38 sites along motorways in 2015, on average were 2 decibel higher than calculated values. At 39 measurement sites along the track, the measured and calculated noise levels in 2015, on average were in agreement. These results are consistent with previous years, 2013 and 2014. At the individual measurement sites, both for motorways and the track, differences may vary from the average. At motorways the measurements are within 2 dB lower and 6 dB higher compared with calculated values, depending on the type and the local condition of the road surface. The comparison of measured and calculated noise levels is a requirement of the environmental management Act. The road- and railway infrastructure manager, Rijkswaterstaat and ProRail, show by calculation whether the noise production from the road or the track complies with established noise limits. The calculated noise levels are validated by RIVM with a sample of measurements. This report also gives the latest results of measurements from 2016 at 45 sites along motorways and 40 sites along the track. The measured noise levels from 2016 will be compared with calculated levels, which will be published by the road- and railway infrastructure manager in the second half of 2017.Ministerie van I&

Intercomparisons of Nine Sky Brightness Detectors

Nine Sky Quality Meters (SQMs) have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across the Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between ±14%. Individual night time sums range from −16% to +20%. Intercalibration reduces this to 0.5%, and −7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 ± 0.003 mcd/m2 on 12 April, and the largest value was 5.94 ± 0.03 mcd/m2 on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent

Two instruments based on differential optical absorption spectroscopy (DOAS) to measure accurate ammonia concentrations in the atmosphere

We present two Differential Optical Absorption Spectroscopy (DOAS) instruments built at RIVM: the RIVM DOAS and the miniDOAS. Both instruments provide virtually interference-free measurements of NH3 concentrations in the atmosphere, since they measure over an open path, without suffering from inlet problems or interference problems by ammonium aerosols dissociating on tubes or filters. They measure concentrations up to at least 200 mu g m(-3), have a fast response, low maintenance demands, and a high up-time. The RIVM DOAS has a high accuracy of typically 0.15 mu g m(-3) for ammonia for 5-min averages and over a total light path of 100 m. The miniDOAS has been developed for application in measurement networks such as the Dutch National Air Quality Monitoring Network (LML). Compared to the RIVM DOAS it has a similar accuracy, but is significantly reduced in size, costs, and handling complexity. The RIVM DOAS and miniDOAS results showed excellent agreement (R-2 = 0.996) during a field measurement campaign in Vredepeel, the Netherlands. This measurement site is located in an agricultural area and is characterized by highly variable, but on average high ammonia concentrations in the air. The RIVM-DOAS and miniDOAS results were compared to the results of the AMOR instrument, a continuous-flow wet denuder system, which is currently used in the LML. Averaged over longer time spans of typically a day, the (mini) DOAS and AMOR results agree reasonably well, although an off-set of the AMOR values compared to the (mini) DOAS results exists. On short time scales, the (mini) DOAS shows a faster response and does not show the memory effects due to inlet tubing and transport of absorption fluids encountered by the AMOR. Due to its high accuracy, high uptime, low maintenance and its open path, the (mini) DOAS shows a good potential for flux measurements by using two (or more) systems in a gradient set-up and applying the aerodynamic gradient technique

Peptide nucleic acids (PNA) derived from N-(N-methylaminoethyl)glycine. Synthesis, hybridization and structural properties

Backbone N-methylated peptide nucleic acids (PNAs) containing the four nucleobases adenine, cytosine, guanine and thymine were synthesized via solid phase peptide oligomerization. The oligomers bind to their complementary target with a thermal stability that is 1.5–4.5°C lower per "N-methyl nucleobase unit' [dependent on the number and position(s) of the N-methyl] than that of unmodified PNA. However, even fully N-methyl modified PNAs bind as efficiently to DNA or RNA targets as DNA itself. Furthermore, the hybridization efficiency per N-methyl unit in a PNA decreased with increasing N-methyl content, and the effect was more pronounced when the N-methyl backbone units are present in the Hoogsteen versus the Watson–Crick strand in (PNA)2-DNA triplexes. Interestingly, CD spectral analyses indicate that 30% (3 out of ten) substitution with N-methyl nucleobases did not alter the structure of PNA-DNA (or RNA) duplexes or (PNA)2-DNA triplexes, and likewise CD spectroscopy and X-ray crystallography showed no major structural differences between N-methylated (30%) and unmodified PNA-PNA duplexes. However, PNA-DNA duplexes as well as triplexes adopted a different conformation when formed with all-N-methyl PNAs

Evaluation study of the suitability of instrumentation to measure ambient NH3 concentrations under field conditions

The uncertainties in emissions of ammonia (NH3) in Europe are large, partially due to the difficulty in monitoring of ambient concentrations due to its sticky nature. In the European Monitoring and Evaluation Program (EMEP) the current recommended guidelines to measure NH3 are by coated annular denuders with offline analysis. This method, however, is no longer used in most European countries and each one has taken a different strategy to monitor atmospheric ammonia due to the increase of commercial NH3 monitoring instrumentation available over the last 20 years. In June 2014, a 3 year project funded under the European Metrology Research Programme, “Metrology for Ammonia in Ambient Air” (MetNH3), started with the aim to develop metrological traceability for the measurement of NH3 in air from primary gas mixtures and instrumental standards to field application. This study presents the results from the field intercomparison (15 instruments) which was held in South East Scotland in August 2016 over an intensively managed grassland. The study compared active sampling methods to a meteorological traceable method which was developed during the project with the aim to produce a series of guidelines for ambient NH3 measurements. Preliminary results highlight both the importance of inlets and management of relative humidity in the measurement of ambient NH3 and of the requirement to carry out frequent intercomparison of NH3 instrumentation. Overall, it would be recommended from this study that a WMO-GAW world centre for NH3 would be established and support integration of standards into both routine and research measurements

Replacing the AMOR with the miniDOAS in the ammonia monitoring network in the Netherlands

In this paper we present the continued development of the miniDOAS, an active differential optical absorption spectroscopy (DOAS) instrument used to measure ammonia concentrations in ambient air. The miniDOAS has been adapted for use in the Dutch National Air Quality Monitoring Network. The miniDOAS replaces the life-expired continuous-flow denuder ammonia monitor (AMOR). From September 2014 to December 2015, both instruments measured in parallel before the change from AMOR to miniDOAS was made. The instruments were deployed at six monitoring stations throughout the Netherlands. We report on the results of this intercomparison. Both instruments show a good uptime of ca. 90 %, adequate for an automatic monitoring network. Although both instruments produce 1 min values of ammonia concentrations, a direct comparison on short timescales such as minutes or hours does not give meaningful results because the AMOR response to changing ammonia concentrations is slow. Comparisons between daily and monthly values show good agreement. For monthly averages, we find a small average offset of 0.65 ± 0.28 µg m−3 and a slope of 1.034 ± 0.028, with the miniDOAS measuring slightly higher than the AMOR. The fast time resolution of the miniDOAS makes the instrument suitable not only for monitoring but also for process studies

Chiral introduction of positive charges to PNA for double-duplex invasion to versatile sequences

Invasion of two PNA strands to double-stranded DNA is one of the most promising methods to recognize a predetermined site in double-stranded DNA (PNA = peptide nucleic acid). In order to facilitate this ‘double-duplex invasion’, a new type of PNA was prepared by using chiral PNA monomers in which a nucleobase was bound to the α-nitrogen of N-(2-aminoethyl)-d-lysine. These positively charged monomer units, introduced to defined positions in Nielsen's PNAs (poly[N-(2-aminoethyl)glycine] derivatives), promoted the invasion without impairing mismatch-recognizing activity. When pseudo-complementary nucleobases 2,6-diaminopurine and 2-thiouracil were bound to N-(2-aminoethyl)-d-lysine, the invasion successfully occurred even at highly G–C-rich regions [e.g. (G/C)7(A/T)3 and (G/C)8(A/T)2] which were otherwise hardly targeted. Thus, the scope of sequences available as the target site has been greatly expanded. In contrast with the promotion by the chiral PNA monomers derived from N-(2-aminoethyl)-d-lysine, their l-isomers hardly invaded, showing crucial importance of the d-chirality. The promotion of double-duplex invasion by the chiral (d) PNA monomer units was ascribed to both destabilization of PNA/PNA duplex and stabilization of PNA/DNA duplexes

Worldwide variations in artificial skyglow

Open access journalDespite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.MILIEU (FU Berlin)Federal Ministry of Education and Research, GermanyEU COST Action ES1204 (Loss of the Night Network)European Research Council (ERC) under the EU's Seventh Framework Program (FP7/2007-2013)panish Network for Light Pollution StudiesNational Aeronautics and Space Administration (Goddard Space Flight Center)Ohio State UniversityUniversity of IowaThe Adam Mickiewicz Universit

Worldwide variations in artificial skyglow

Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program