Fant 9759 publikasjoner. Viser side 190 av 391:
2016
2022
Low-Processing Data Enrichment and Calibration for PM2.5 Low-Cost Sensors
Particulate matter (PM) in air has been proven to be hazardous to human health. Here we focused on analysis of PM data we obtained from the same campaign which was presented in our previous study. Multivariate linear and random forest models were used for the calibration and analysis. In our linear regression model the inputs were PM, temperature and humidity measured with low-cost sensors, and the target was the reference PM measurements obtained from SEPA in the same timeframe.
2023
2011
Denne rapporten går igjennom status innen mikrosensorteknologien. Den vurderer tilgjengelighet av produkter på markedet, målte parametere og datakvalitet, samt hvilke muligheter sensorene åpner for når de blir brukt riktig.
NILU
2021
Poland continues to rely heavily on coal and fossil fuels for household heating, despite efforts to reduce Particulate Matter (PM) levels. The availability of reliable air quality data is essential for policymakers, environmentalists, and citizens to advocate for cleaner energy sources. However, Polish air quality monitoring is challenging due to the limited coverage of reference stations and outdated equipment. Here, we report the results of a study on the spatio-temporal variability of Particulate Matter in Legionowo, Poland, using residents’ network of low-cost sensors. Along with identifying the hotspots of household-emitted PM, (1) we propose a data quality assurance scheme for PM sensors, (2) suggest an approach for estimating the Relative Humidity-induced uncertainty in the sensors without co-location with reference instruments, and (3) develop an interpretable Machine Learning (ML) model, a Generalized Additive Model (RMSE = 6.16 μg m−3, and R2 = 0.88), for unveiling the underlying relations between PM2.5 levels and other environmental parameters. The results in Legionowo suggest that as air temperature and wind speed increase by 1 °C and 1 km h−1, PM2.5 would respectively decrease by 0.26 μg m−3 and 0.14 μg m−3 while PM2.5 increases by 0.03 μg m−3 as RH increases by 1%.
Elsevier
2023
2013
Low-Cost Particulate Matter Sensors for Monitoring Residential Wood Burning
Conventional monitoring systems for air quality, such as reference stations, provide reliable pollution data in urban settings but only at relatively low spatial density. This study explores the potential of low-cost sensor systems (LCSs) deployed at homes of residents to enhance the monitoring of urban air pollution caused by residential wood burning. We established a network of 28 Airly (Airly-GSM-1, SP. Z o.o., Poland) LCSs in Kristiansand, Norway, over two winters (2021–2022). To assess performance, a gravimetric Kleinfiltergerät measured the fine particle mass concentration (PM2.5) in the garden of one participant’s house for 4 weeks. Results showed a sensor-to-reference correlation equal to 0.86 for raw PM2.5 measurements at daily resolution (bias/RMSE: 9.45/11.65 μg m–3). High-resolution air quality maps at a 100 m resolution were produced by combining the output of an air quality model (uEMEP) using data assimilation techniques with the network data that were corrected and calibrated by using a proposed five-step network data processing scheme. Leave-one-out cross-validation demonstrated that data assimilation reduced the model’s RMSE, MAE, and bias by 44–56, 38–48, and 41–52%, respectively.
2023
2015
2019
2008
Low concentrations of persistent organic pollutants (POPs) in air at Cape Verde
Ambient air is a core medium for monitoring of persistent organic pollutants (POPs) under the Stockholm Convention
and is used in studies of global transports of POPs and their atmospheric sources and source regions. Still,
data based on active air sampling remain scarce in many regions. The primary objectives of this study were to
(i) monitor concentrations of selected POPs in air outside West Africa, and (ii) to evaluate potential atmospheric
processes and source regions affecting measured concentrations. For this purpose, an active high-volume air
sampler was installed on the Cape Verde Atmospheric Observatory at Cape Verde outside the coast of West
Africa. Sampling commenced in May 2012 and 43 samples (24 h sampling) were collected until June 2013. The samples were analyzed for selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB) and chlordanes. The concentrations of these POPs at Cape Verde were generally low and comparable to remote sites in the Arctic for several compounds. Seasonal trends varied between compounds and concentrations exhibited strong temperature dependence for chlordanes. Our results indicate
net volatilization fromthe Atlantic Ocean north of Cape Verde as sources of these POPs. Air mass back trajectories
demonstrated that air masses measured at Cape Verdewere generally transported fromthe Atlantic Ocean or the North African continent. Overall, the low concentrations in air at Cape Verde were likely explained by absence of major emissions in areas from which the air masses originated combined with depletion during long-range atmospheric
transport due to enhanced degradation under tropical conditions (high temperatures and concentrations of hydroxyl radicals).
Elsevier
2018
2001
2011