Over the past decade, a range of sensor technologies became available on the market, enabling a revolutionary shift in air pollution monitoring and assessment. With their cost of up to three orders of magnitude lower than standard/reference instruments, many avenues for applications have opened up. In particular, broader participation in air quality discussion and utilisation of information on air pollution by communities has become possible. However, many questions have been also asked about the actual benefits of these technologies. To address this issue, we conducted a comprehensive literature search including both the scientific and grey literature. We focused upon two questions: (1) Are these technologies fit for the various purposes envisaged? and (2) How far have these technologies and their applications progressed to provide answers and solutions? Regarding the former, we concluded that there is no clear answer to the question, due to a lack of: sensor/monitor manufacturers' quantitative specifications of performance, consensus regarding recommended end-use and associated minimal performance targets of these technologies, and the ability of the prospective users to formulate the requirements for their applications, or conditions of the intended use. Numerous studies have assessed and reported sensor/monitor performance under a range of specific conditions, and in many cases the performance was concluded to be satisfactory. The specific use cases for sensors/monitors included outdoor in a stationary mode, outdoor in a mobile mode, indoor environments and personal monitoring. Under certain conditions of application, project goals, and monitoring environments, some sensors/monitors were fit for a specific purpose. Based on analysis of 17 large projects, which reached applied outcome stage, and typically conducted by consortia of organizations, we observed that a sizable fraction of them (~ 30%) were commercial and/or crowd-funded. This fact by itself signals a paradigm change in air quality monitoring, which previously had been primarily implemented by government organizations. An additional paradigm-shift indicator is the growing use of machine learning or other advanced data processing approaches to improve sensor/monitor agreement with reference monitors. There is still some way to go in enhancing application of the technologies for source apportionment, which is of particular necessity and urgency in developing countries. Also, there has been somewhat less progress in wide-scale monitoring of personal exposures. However, it can be argued that with a significant future expansion of monitoring networks, including indoor environments, there may be less need for wearable or portable sensors/monitors to assess personal exposure. Traditional personal monitoring would still be valuable where spatial variability of pollutants of interest is at a finer resolution than the monitoring network can resolve.

Applications of low-cost sensing technologies for air quality monitoring and exposure assessment: How far have they gone?

From low-cost sensors to high-quality data: A summary of challenges and best practices for effectively calibrating low-cost particulate matter mass sensors

Anthropogenic activities in and around the urban highways followed by aerodynamic processing generate street dusts, which can cause adverse health effects through different exposure pathways. Hence, considering the high degree of industrialization, concomitant unplanned urbanization, and rapid demographic augmentation, street dust samples from an urban city (Gazipur, Bangladesh) were investigated in terms of potentially toxic elements (using ICP-MS) to evaluate their ecological and health risks. Mean concentrations (± SD) of lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), zinc (Zn), nickel (Ni), and arsenic (As) in the analyzed air-dried samples were 40.9 ± 13.6, 44.9 ± 15.4, 83.3 ± 19.0, 9.1 ± 5.4, 239.1 ± 34.7, 33.5 ± 10.4, and 2.1 ± 0.8 mg/kg, respectively with heterogeneous distribution which were 0.2 (As) to 82.7 (Cd) times higher than the available internationally recommended limits. Element-specific environmental indices revealed that contamination levels followed the descending order as Cd > Zn > Cu > Pb > Cr > Ni > As, whereas individual ecological risks followed the descending order as Cd > Cu > Pb > Ni > Zn > Cr > As. Sampling site-specific composite indices indicated that sampling sites with high loadings of traffic, population, industrialization, and urbanization were mostly polluted. Multivariate statistical approaches also deduced the similar origins of the studied elements. In terms of the investigated elements, the study site possessed high potential ecological risks, although non-carcinogenic and carcinogenic risks through different pathway’s exposures seem insignificant, where children are more vulnerable than adults.

Potentially toxic elements in street dust from an urban city of a developing country: ecological and probabilistic health risks assessment

This is the first study, 10 years after the war activities, to report about the content of heavy metals and metalloids, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) found in samples of soils from selected playgrounds in Sarajevo. Due to the fact that children are in direct contact with surface soils, it has been recommended that children’s playgrounds should be given special consideration in this respect. Basic properties (pH in H2O, pH in 1 mol dm−3 KCl, humus, and CaCO3) of the examined soils were determined. Samples for the determination of heavy metals and metalloids were prepared by microwave-assisted acid digestion and determined by using an inductively coupled plasma optical emission spectrometer. Fluorine was determined potentiometrically. Gas chromatography with mass spectrometry was used for determination of PAHs and PCBs. Determined contents (mg kg−1) for Cd, Pb, Hg, Cr, Ni, Cu, Zn, Co, Mo, Fe, Se, As, B, and F were in the ranges from: 0.031 ± 0.03 to 0.52 ± 0.05; 26.1 ± 2.5 to 47.7 ± 4.5; 0.07 ± 0.01 to 0.50 ± 0.08; 26.2 to 50; 19.5 ± 1.6 to 33.3 ± 2.7; 12.8 ± 1.8 to 31.9 ± 4.5; 56.0 ± 4.0 to 89.0 ± 6.5; 6.7 ± 0.6 to10.6 ± 1.0; <0.8; 3.05 to 7.35; 1.98 to 2.60; 6.5 ± 0.8 to 17.2 ± 2.0; 0.4 to 3.6, and 286 to 575, respectively. The total PAHs ranged between 0.184 ± 0.32 mg kg−1 and 7.983 ± 1.389 mg kg−1. The total PCBs was <0.002 mg kg−1. Our preliminary results may contribute to more accurate health risk assessments of the soils, and may be included in projects planning children’s health risk assessments and adopting environmental legislation which has not been sufficiently regulated in Bosnia and Herzegovina so far.

Soil pollution fingerprints of children playgrounds in Sarajevo city, Bosnia and Herzegovina.

The aim of this study was to assess contamination and potential human health risks of heavy metals in street dust from the Federation of Bosnia and Herzegovina (FB&H). In total, 117 street dust sam...

Health risk assessment of heavy metal contamination in street dust of federation of Bosnia and Herzegovina

. In this paper we evaluate characteristics of three optical particulate matter sensors/sizers (OPS): high-end spectrometer
11-D (Grimm, Germany), low-cost sensor OPC-N2 (Alphasense, United Kingdom) and in-house developed MAQS
(Mobile Air Quality System), which is based on another
low-cost sensor – PMS5003 (Plantower, China), under realistic conditions of strong and mild urban pollution. Results were compared against a reference
gravimetric system, based on a Gemini (Dadolab, Italy), 2.3 m 3  h −1 air sampler, with two channels (simultaneously measuring PM 2.5 and PM 10 concentrations).
The measurements were performed in Sarajevo, the capital of Bosnia-Herzegovina, from December 2019 until May 2020.
This interval is divided into period 1 – strong pollution – and period 2 – mild pollution. The city of Sarajevo is one of the most polluted cities in Europe in terms of particulate matter: the average concentration of PM 2.5 
during the period 1 was 83  µ g m −3 , with
daily average values exceeding 500  µ g m −3 . During period 2, the average concentration of
PM 2.5 was 20  µ g m −3 . These conditions represent a good opportunity to test optical devices against the reference instrument in a wide range of ambient particulate matter (PM) concentrations. The effect of an in-house developed diffusion dryer for 11-D is discussed as well. In order to analyse the mass distribution of particles, a scanning mobility particle sizer (SMPS), which together with the 11-D spectrometer gives the full spectrum from nanoparticles of diameter 10 nm to coarse particles of diameter 35  µ m, was used.
All tested devices showed excellent correlation with the
reference instrument in period 1, with R2 values between 0.90 and 0.99 for daily average PM concentrations. However, in period 2, where the range of concentrations was much narrower,
 R2 values decreased significantly, to values from 0.28 to 0.92. We have also included results of a 13.5-month long-term comparison of our MAQS sensor with a nearby beta attenuation monitor (BAM) 1020 (Met One Instruments, USA) operated by the United States Environmental Protection Agency (US EPA), which showed similar correlation and no observable change in performance over time.

/pdf/evaluation-of-optical-particulate-matter-sensors-under-43a3yi8ndf.pdf

Evaluation of optical particulate matter sensors under realistic conditions of strong and mild urban pollution

Heavy metal pollutant in urban street dust has become a growing concern in recent years. Street dust samples from urban and suburban areas were collected from the Sarajevo area, Bosnia and Herzegovina, during the spring season of 2013. Samples were collected from low and high density traffic roads, industrial zones, parks, parking places, hospitals and local health centres, school gardens. The levels of heavy metals of street dusts were determined by flame atomic absorption spectrometry (FAAS). Cadmium, chromium, copper, nickel, iron, manganese, lead and zinc levels in the dust samples were found in the range of 0.58–3.65, 3.42–60.82, 5.49– 388, 9.31–161, 647–2244, 6.10–13.32, 31.63-1760 and 40.29–378 μg/g, respectively. The highest metal concentrations were found in samples from industrial zone and in the streets with heavy traffic. The lowest levels of the metal concentrations were found in the samples from health centres and school gardens. The concentrations of the metals were, in most of cases, similar to the mean world-wide contents of the street dust samples. Correlations between heavy trace metal levels of the dust samples were also evaluated.

/pdf/heavy-metals-in-street-dust-in-sarajevo-area-bosnia-and-s85shf1nal.pdf

Heavy Metals in Street Dust in Sarajevo Area, Bosnia and Herzegovina

The main objective of this study is to assess the level of contamination from mercury and other elements in the Sarajevo area. The soil and lichen samples (Hypogymnia physodes) were collected from selected areas there were nine soil sites and four sites for lichens. Validated and standardized analytical procedures were used in order to compare the obtained results with data from other countries in Europe. The accuracy of the results obtained by cold vapour atomic absorption spectrometry (CVAAS) for total mercury and instrumental neutron activation analysis (INAA) for other elements (Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Eu, Fe, Ga, Hf, Ho, In, K, La, Mo, Na, Nd, Pd, Pr, Rb, Ru, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Tm, U, W, Yb, Zn, and Zr) was verified by the use of certified reference materials. Results obtained for mercury showed that at three sites (Butmir, PMF, and Blekin potok) the mercury concentrations in the soil were much higher, 5 to 10 times higher, than the allowed values. All lichens samples examined contained low mercury concentrations that cannot be correlated with the mercury contents in the soil. Comparison of the multielemental analysis of the lichen H. physodes and surface soils samples is also presented.

https://www.ekoloji.com.tr/resimler/97-4.pdf

Sabina Zero

Papers

Evaluation of optical particulate matter sensors under realistic conditions of strong and mild urban pollution

Heavy Metals in Street Dust in Sarajevo Area, Bosnia and Herzegovina

Multielement and Rare Earth Element Composition of the Soil and Lichen from Sarajevo, Bosnia and Herzegovina

Assessment of metals and their estimated daily intakes in various nuts