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© 2022 Elsevier B.V.Approximately 15.4 million people are continuously exposed to various air pollutants in the megacity of Istanbul. Anthropogenic activities in Istanbul generate emissions from mobile sources (i.e., vehicles, aircraft, ships, etc.) and stationary sources such as industrial and residential heating emissions. Biogenic emissions and long-range transport such as desert dust from Sahara and pollutants from Balkan countries also contribute to the local air pollution in Istanbul. In this work, fine (Dp 2.5 μm) particles were collected with a high-volume sampler during four seasons of the period Jan 2017 - Jan 2018. A total of 15 PAHs and 28 n-alkanes were identified and quantified with a newly developed thermal desorption – gas chromatography with mass spectrometry method (TD-GC–MS). Source analysis was performed with PAH and n-alkane diagnostic ratios, and source apportionment was performed with principal component analysis. The yearly averages of PAHs and n-alkanes in the fine fraction were 21.6 ng m−3 and 103.8 ng m−3, with daily averages of 7.1–80.8 ng m−3 and 55.3–204.2 ng m−3, respectively. Approximately 90% of the PAHs and n-alkanes were found in the fine PM fraction in this traffic site. The BaP carcinogenic (BaP-TEQ) and mutagenic (BaP-MEQ) equivalents were on average 5.47 ± 0.64 and 4.72 ± 0.8 ng m−3 in the fine fraction, respectively, and were approximately 6–7 times lower in the coarse fraction. This has important implications due to the respirable nature of fine aerosols and their longer lifetimes in the atmosphere. Multivariate analysis coupled with principal component analysis led to an important result that the organic aerosol mainly originates from two local sources: road traffic (50.4%) and shipping emissions (26.6%). The results found in this work indicate the urgent need for the application of mitigation measures to control road traffic and minimize the emissions from ships passing through the İstanbul Bosphorus.

© 2022, The Author(s), under exclusive licence to Springer Nature B.V.Considering an integrated approach to assess all of the measured pollutants in a diurnal, monthly, seasonal, and annual time scales and understanding the mechanisms hidden under low air quality conditions are essential for tackling potential air pollution issues. Konya, located in central Anatolia, is the largest province of Turkey with a surface area of 40,838 km2 and has different industrial activities. The lack of recent detailed studies limits our information on the underlying air pollution levels in Konya and obscuring policymakers to develop applicable mitigation measures. In this study, we used hourly monitored air quality data of CO, NO2, NOx, PM10, PM2.5, and SO2 from five stations in Konya and investigated the temporal and spatial variabilities for the 2008–2018 period via statistical analysis. Upon analysis, particulate matter was found to be the dominant pollutant deteriorating the air quality of Konya. The highest 2008–2018 periodic mean value of PM10 was found in Karatay Belediye as 70.5 µg/m3, followed by 67.4 µg/m3 in Meram, 58.7 µg/m3 in Selçuklu, and 43.7 µg/m3 in Selçuklu Belediye. The 24-h limit value of PM10 given as 50 µg/m3 in the legislation was violated in all of the stations, mainly during winter and autumn. High positive correlations were found among the stations, and the highest correlation was obtained between Selçuklu Belediye and Karatay Belediye with a Pearson correlation coefficient of 0.77. Long-term data showed a decreasing trend in PM10 concentrations. Diurnal variability is found to be more pronounced than weekly variability. For almost all of the pollutants, except for photochemical pollutants like O3, a prominent result was the nighttime and morning rush hours high-pollutant levels. A case study done for the January 29, 2018 to February 05, 2018 episode showed the importance of meteorology and topography on the high levels of pollution. Limitation of the pollutant transport and dilution by meteorological conditions and the location of Konya on a plain surrounded by high hills are believed to be the main reasons for having low air quality in the region.

Organic aerosol (OA) is an important fraction of fine particulate matter. Most primary OA emissions comprise semivolatile organic compounds (SVOCs) that are reactive and may partition into particle and vapor phases. Collection of SVOCs in the particle phase at high time resolution reduces positive and negative artifacts, but requires sensitive analytical techniques for chemical characterization. In this work, we investigated the effect of thermal desorption-gas chromatography/mass spectrometry (TD-GC-MS) analytical variables on 16 polycyclic aromatic hydrocarbons (PAHs) and 29 n-alkanes. Analytical responses of target compounds were mostly influenced by trap desorption time and GC column pressure. The optimal TD-GC-MS trap desorption conditions were 350 degrees C for 10 min at GC constant pressure mode of 17 psi. Good linearity (R-2 > 0.99) was observed for all target analyzes (with the exception of 6 ring PAHs and C-35-C-39 n-alkanes). Method detection limits were 0.038-0.157 ng m(-3 )and 0.028-0.355 m(-)(3) for PAHs and n-alkanes, respectively. The optimized method was tested on PM2.5 samples collected with the high-volume sampling technique at high temporal resolution of 2 h. Analysis of a sample, followed by analysis of a blank, did not show carryover. The optimized TD-GC-MS method showed the capability to resolve diurnal variations of target analyzes in high time resolved PM2.5. Using TD-GC-MS for analysis of high time resolved PM2.5 will contribute to the improvement of source apportionment, emission inventories, and global chemistry-climate models.

The seasonal variation of fine carbonaceous aerosol was evaluated in an urban traffic site in Istanbul. PM2.5 samples were collected on selected days during four seasons between Jan 2017–Jan 2018. Daily PM2.5 concentrations were obtained experimentally by the gravimetric method in Besiktas, while hourly concentrations were obtained from the Air Quality Monitoring Network of Istanbul in Catladikapi, Silivri, Kagithane, and Umraniye. Organic carbon (OC) and elemental carbon (EC) concentrations were determined by a thermo-optical carbon analyzer for samples collected in Besiktas. The 24-h US-EPA air quality standard of 35 μg m−3 was exceeded 13, 25, 41, 42, and 57% of the time in Catladikapi, Silivri, Kagithane, Umraniye, and Besiktas, respectively. These exceedances occurred mainly during the fall and winter owing to a combination of emissions from fuel combustion for residential heating, traffic and industry, and poor air dispersion due to weak atmospheric motion and low mixing heights. Average OC concentrations ranged as 6.62–7.32 μg m−3 during spring and summer, and 13.76–14.1 μg m−3 during fall and winter. The OC concentrations observed in this work during the summer and winter were 2–4 and 3–6 times higher than concentrations observed in the USA and Europe, respectively. The EC concentrations did not show considerable seasonal variation, with values between 2.16 and 3.26 μg m−3. EC concentrations in Besiktas were 7 and 9 times higher than concentrations observed in the USA and Europe, in order. Results obtained in this study could be helpful for future implementation of policies and strategies to reduce emissions from combustion sources in order to comply with the air quality standards.

Organic Carbon (OC) and Elemental Carbon (EC) were investigated on selected days between January 2017 and January 2018 in an urban area heavily impacted by traffic in Istanbul megacity. 300 PM2.5 samples were collected with a time resolution of 2 h during the daytime between 07:00–19:00. Nighttime samples were collected with a time resolution of 12 h between 19:00–07:00. Samples were collected for three weeks during the winter and one week during the spring, summer, and fall. The daily PM2.5 concentrations exceeded the standard of 35 μg m−3 29% of the time. Air quality was classified as fair (PM2.5>26.4 μg m−3) and unhealthy (PM2.5>39.9 μg m−3) 43% and 20% of the days, respectively. The annual average OC and EC were 11.3 ± 4.91 and 4.1 ± 1.16 μg m−3, respectively. Organic carbon showed strong seasonal variation with high concentrations during the heating season and low concentrations during the summer. Elemental carbon did not show strong seasonality due to the continuous influence of heavy traffic. Diurnal variations of OC and EC were characterized by high concentrations during the morning and evening rush hours, and low concentrations in the middle of the day due to the dilution effect of an increased mixing layer. Formation of secondary organic carbon was uncertain during the summer due to dilution and low primary organic carbon emissions. Concentrations heavily depended on surface wind speed. Average OC concentrations were 56–72% higher at wind speeds lower than 2 m s−1 compared to that at wind speeds higher than 3 m s−1 during fall and winter. Higher EC concentrations (15–56%) were observed at wind speeds higher than 3 m s−1, showing that in addition to traffic emissions, EC was transported from nearby areas. Continuous measurements of high time resolved OC and EC are necessary for the development and evaluation of air pollution mitigation strategies, particularly from combustion sources.

Vapor- and aerosol-phase atmospheric organic matter were collected in East St. Louis, MO using the high-volume sampling method. Samples were processed by traditional analytical methods and analyzed by multidimensional gas chromatography with time-of-flight mass spectrometric detection. Levels of identified, hydrocarbon-like organic vapor and aerosol species (i.e., HOV and HOA, respectively) were 10–42 ng m−3 and 0.020–3.6 ng m−3, respectively. Concentrations of identified, oxygenated organic vapor and aerosol species (i.e., OOV and OOA, respectively) were 2–66 ng m−3 and 23–310 ng m−3, respectively. The principal feature of the HOV was an unresolved complex mixture that represented 54.5 ± 11.3% of the total HOVs during the field campaign. Levels of n- and branched alkanes, alkyl and cycloalkylbenzenes, polyaromatic hydrocarbons (PAHs), and alkyl-substituted PAHs generally declined from the morning rush hour to the 1000–1400 sampling period, which was similar to the expected trend in reactivity with respect to OH. The OOV included aliphatic mono-carboxylic acids, aliphatic and aromatic alcohols, aldehydes, and ketones, and alicyclic ketones, alcohols, and epoxides (i.e., montoterpenoids). The bulk of the OA species (∼99%) were a complex mixture of OOA, which included multifunctional n-aliphatic, alicyclic, and aromatic hydrocarbons, dicarboxylic and ketocarboxylic aliphatic and dicarboxylic monoaromatic acids, lactones, tetrols, and pentitols. The sampling and analytic techniques provided quantitative molecular information for HOVs in ambient air, which are a missing source of secondary organic aerosol precursors. Molecular characterization and quantitation of HOVs and OOA species will facilitate predictions of SOA formation using molecular-specific models.

Mineral dust is the most significant source of natural particulate matter. In urban regions, where > 50% of the world population is currently living, local emissions of particulate matter are further aggravated by mineral dust loadings from deserts. The megacity of Istanbul is located in an area sensitive to local pollution due to transportation (i.e., private cars, public transportation, aircrafts, ships, heavy diesel trucks, etc.), industrial emissions, residential heating, and long-range transport from Europe, Asia, and deserts. In this work, the effect of desert dust transport on PM 10 concentrations and physical properties was investigated for the period of 2007–2014 in the touristic area of Aksaray, Istanbul. The Dust Regional Atmospheric Model (DREAM8b) was used to predict dust loading in Istanbul during dust transport events. Variations on surface PM 10 concentrations were investigated according to seasons and during dust transport events. Cluster analysis of air mass backward trajectories was useful to understand frequency analysis and air mass trajectory dependence of PM 10 concentrations on dust loadings. The effect of desert dust transport on aerosol optical depths was also investigated. It was observed that PM 10 concentrations exceeded the air quality standard of 50 μg m − 3 50% of the time during the study period. The largest number of exceedances in air quality standard occurred during the spring and winter seasons. Approximately 40–60% of the dust loading occurs during the spring. Desert dust and non-desert dust sources contribute to 22–72% and 48–81% of the ground-level PM 10 concentrations in Aksaray, Istanbul during the study period. Averaged AOD observed during dust transport events in spring and summer ranged 0.35–0.55. Cluster analysis resolved over 82% the variability of individual air mass backward trajectories into 5 clusters. Overall, air masses arriving to Istanbul at 500 m are equally distributed into northern (52%) and southern (48%). Frequency analysis of PM 10 concentrations with mean air mass backward trajectories showed that PM 10 from local anthropogenic sources may be enhanced by long-range transport from the African Desert, Asian Desert, Arabian Peninsula, Russia, and Ukraine. The work presented here provides the first integrated assessment for evaluation of occurrence and quantification of the effect of dust transport to ground-level PM 10 concentrations in Istanbul, which is helpful for human health prevention and implementation of air quality control measures.

The conventional analytical studies to determine ozone formation potential (OFP) and potential sources currently ignore the destruction of non-methane hydrocarbons (NMHCs) during atmospheric transport, namely chemical loss. The chemical loss of NMHCs was estimated using photochemical age based on the online observation data of NMHCs from the Guangzhou Panyu Atmospheric Composition Station (GPACS) in the Pearl River Delta (PRD) during summer (June, July, and August) and autumn (September, October, and November) - two seasons favorable to the photochemical generation of ozone - of 2012. Subsequently, the composition characteristics, OFPs, and potential sources of the NMHCs were analyzed under the condition of atmospheric photochemical loss. The results showed that the initial mixing ratios of NMHCs (i.e., the mixing ratios after discharge from emission sources, before they experience any significant atmospheric chemical reaction), during summer (37.30 ppbv) and autumn (41.62 ppbv) were 6.90 ppbv and 5.98 ppbv higher than the observed, respectively. Four maximum incremental reactivity (MIR) scales were used to calculate the OFP for NMHCs seasonal losses. The obtained OFPs were 62.67 ppbv, 73.05 ppbv, 73.31 ppbv, and 68.51 ppbv in summer and 47.71 ppbv, 55.54 ppbv, 56.12 ppbv, and 52.68 ppbv in autumn as calculated by the respective MIR scales. Both the MIR and the propylene-equivalent mixing ratio reflect the reactivity of various NMHC species to a certain extent. Isoprene, toluene, and xylene were found key species for controlling ozone. Based on the source analysis of the initial mixing ratio of NMHCs, vehicle emissions and solvent consumption were the major sources in Guangzhou.

The following algorithm, which is based on the thermodynamics of nonelectrolyte partitioning, was developed to predict emission rates of terpenes and terpenoids from specific storage sites in conifers: E i = x o r i γ o r i p i ∘ where Ei is the emission rate (μg C gdw−1 h−1) and p i ∘ is the vapor pressure (mm Hg) of the pure liquid terpene or terpenoid, respectively, and x o r i and γ o r i are the mole fraction and activity coefficient (on a Raoult's law convention), respectively, of the terpene and terpenoid in the oleoresin. Activity coefficients are calculated with Hansen solubility parameters that account for dispersive, polar, and H-bonding interactions of the solutes with the oleoresin matrix. Estimates of p i ∘ at 25 °C and molar enthalpies of vaporization are made with the SIMPOL.1 method and are used to estimate p i ∘ at environmentally relevant temperatures. Estimated mixing ratios of terpenes and terpenols were comparatively higher above resin-acid- and monoterpene-rich oleoresins, respectively. The results indicated a greater affinity of terpenes and terpenols for the non-functionalized and carboxylic acid containing matrix through dispersive and H-bonding interactions, which are expressed in the emission algorithm by the activity coefficient. The correlation between measured emission rates of terpenes and terpenoids for Pinus strobus and emission rates predicted with the algorithm were very good (R = 0.95). Standard errors for the range and average of monoterpene emission rates were ±6 – ±86% and ±54%, respectively, and were similar in magnitude to reported standard deviations of monoterpene composition of foliar oils (±38 – ±51% and ±67%, respectively).

A carbon number-functionality grid (CNFG) for a complex mixture of secondary organic aerosol (SOA) precursors and oxidation products was developed from the theoretical retention index diagram of a multidimensional gas chromatographic (GC × 2GC) analysis of a mixture of SOA precursors and derivatized oxidation products. In the GC × 2GC analysis, comprehensive separation of the complex mixture was achieved by diverting the modulated effluent from a polar primary column into 2 polar secondary columns. Column stationary phases spanned the widest range of selectivity of commercially available GC analytic columns. In general, separation of the species by the polar primary column was by the number of carbon atoms in the molecule (when the homologous series of reference compounds was selected to have molecular volumes and functionalities similar to the target analytes) and the polar secondary columns provided additional separation according to functionality. An algebraic transformation of the Abraham solvation parameter model was used to estimate linear retention indices of solutes relative to elution of a homologous series of methyl diesters on the primary and secondary columns to develop the theoretical GC × 2GC retention diagram. Retention indices of many of the oxidation products of SOA precursors were estimated for derivatized forms of the solutes. The GC stationary phases selected for the primary column [(50%-Trifluoropropyl)-methylpolysiloxane] and secondary columns (90% Cyanopropyl Polysilphenylene-siloxane and Polyethylene Glycol in a Sol-Gel matrix) provided a theoretical separation of 33 SOA precursors and 98 derivatized oxidation products into 35 groups by molecular volume and functionality. Comprehensive analysis of extracts of vapor and aerosol samples containing semivolatile SOA precursors and oxidation products, respectively, is best accomplished by (1) separating the complex mixture of the vapor and underivatized aerosol extracts with a (50%-Trifluoropropyl)-methylpolysiloxane × 90% Cyanopropyl Polysilphenylene-siloxane × Polyethylene Glycol in a Sol-Gel matrix arrangement and (2) derivatizing the aerosol extract and reanalyzing the sample on the GC × 2GC column combination. Quantifying groupings and organic molecular species in time series of collections of vapor- and aerosol-phase atmospheric organic matter is a promising analytic technique for measuring production of SOA and evaluating transformations of SOA precursors.

Two, 3-step methods for derivatizing mono- and multi-functional species with carbonyl (CO), carboxylic acid (-COOH), and alcohol (-OH) moieties were compared and optimized. In Method 1, the CO, -COOH, and -OH moieties were converted (1) to methyloximes (R-CN-OCH3) with O-methylhydroxylamine hydrochloride (MHA), (2) to methyl esters (OC-R-OCH3) with (trimethylsilyl)diazomethane in methanol (TMSD/MeOH), and (3) to trimethylsilyl ethers [R-OSi(CH3)3] with N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane (TMCS), respectively. Steps 1 and 3 of both methods were identical; however, in Step 2 of Method 2, -COOH moieties were derivatized with 10% (v/v) boron trifluoride (BF3) in MeOH or n-butanol (n-BuOH). The BF3/MeOH and BF3/n-BuOH were ineffective at converting species with more than 2-OH moieties. Average standard deviations for derivatization of 36 model compounds by the 3-step methods using TMSD/MeOH and BF3/(MeOH) were 7.4 and 14.8%, respectively. Average derivatization efficiencies for Methods 1 and 2 were 88.0 and 114%, respectively. Despite the lower average derivatization efficiency of Method 1, distinct advantages included a greater certainty of derivatization yield for the entire suite of mono- and multi-functional species and fewer processing steps for sequential derivatization. Detection limits for Method 1 using GC×GC-ToF-MS were 0.3-54pgm(-3). Approximately 100 oxygenated organic species were identified and quantified in aerosol filtered from 39m(3) of air in an urban location. Levels of species were 0.013-17ngm(-3) and were nearly all above the Method 1 limit of detection.

Elastase levels are an important marker of the extent and severity of inflammatory processes. We describe a visual immunoassay based on two monoclonal antibodies for the semi-quantitative determination of plasma elastase levels. The method is rapid, reliable, easy to perform, and does not require special laboratory equipment. There is coincidence of our results with those obtained by quantitative methods. The assay is suitable to obtain information for the management of patients in most intensive care units.