Browsing by Author "Nikolova Y."

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    Modelling of ambient air PM2.5 concentration for air quality assessment
    (2015-01-01) Nikolova Y.; Ilieva N.; Sokolovski E.
    During the last decade special attention to the fine particles up to 2,5 μm (PM2.5) is being paid. PM2.5 is treated as a particular pollutant with strong negative impacton human health. In Bulgaria, the levels of PM2.5 are measured only at 9 monitoring stations. Therefore effective air quality monitoring regarding this pollutant can not be expected. In many cases particulate matter with aerodynamic diameter up to 10 μm (PM10) and PM2.5 have common origin. That is why it can be assumed that their concentrations in the air are related. Measured data from two of the monitoring stations ``Kopitoto`` (background) and ``Krasno Selo`` (traffic related) have been investigated. It was established that a strong correlation for ``Krasno Selo`` station exists. Conversely, for ``Kopitoto`` station the correlation is rather weak. A mathematical model has been worked out for calculation of PM2.5 concentration using PM10 concentration data. The model demonstrates good accuracy for urban background and traffic related monitoring stations.
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    Sensors applicability for PM2.5 and PM10 air concentration measurements
    (2018-01-01) Ilieva N.; Nikolova Y.; Predyov I.; Kozarev N.
    Comparisons of Private Stations (PS) measurements with Automatic Monitoring Stations (AMS) included in the National Environmental Monitoring System of the Ministry of Environment and Waters in Bulgaria has been made. The chosen PS (a total of four) are located close to AMS. In order to check whether the PS data are reliable and could be used for air quality monitoring, a statistical analysis of the data from the PS and the AMS was performed. The concentrations measured by two methods are quite different, but a good correlation between them has been established. In order to improve the PS measurement accuracy models for correction of the PM10 and PM2.5 concentrations measured using sensors were derived. They are characterized with good accuracy but are only valid for the warm part of the year. It is necessary to derive another set of coefficients for the cold half of the year. Without correction, the PS measurement error is large and their records may be misleading.