Monitoring of long-term personal exposure to fine particulate matter (PM<Subscript>2.5</Subscript>)

Personal monitoring is of a demanding nature; thus, it is very difficult to obtain personal data for periods longer than a few days or a maximum of a few weeks. To fill this gap, we have performed a study in which personal exposure to particulate matter of aerodynamic diameter under 2.5 μm (PM_2.5) was monitored for almost 1 year. One healthy, adult, non-smoking, female student living in Prague (Czech Republic) was involved in the study. A battery-operated, fast-responding nephelometer was worn by the individual for a period of 10 months, recording PM_2.5 concentration every 5 min. A written time activity diary was used to record the experimental person's movement and the microenvironments visited. The dataset was divided into 12 different (seven indoor and four outdoor and transit) microenvironments. The overall average of the year-long measurement was 14.9 ± 52.5 μg.m⁻³ (median, 8.0 μg.m⁻³). The highest PM_2.5 average concentration was detected in restaurant microenvironments (294.4 μg.m⁻³), while the second highest concentration was recorded in an indoor microenvironment heated by wood and coal stoves (112.2 μg.m⁻³). The lowest mean aerosol concentrations were detected outdoors in a rural/natural environment (7.0 μg.m⁻³) and indoors at the monitored person's home (9.3 μg.m⁻³). During the measurement period, isolated and brief, but very high concentration excursions over 500 μg.m⁻³ or even over 1,000 μg.m⁻³ were recorded. However, they accounted for less than 0.5% of the total time of personal exposure. We conclude that continuous long-term monitoring is a good tool capable of disclosing the frequency and severity of short-term peak events of high particulate concentrations, which may be associated with adverse health effects.     

Preliminary monitoring of concentration of particulate matter (PM<Subscript>2.5</Subscript>) in seven townships of Yangon City,Myanmar

Background

Airborne particulate pollution is more critical in the developing world than in the developed countries in which industrialization and urbanization are rapidly increased. Yangon, a second capital of Myanmar, is a highly congested and densely populated city. Yet, there is limited study which assesses particulate matter (PM_2.5) in Yangon currently. Few previous local studies were performed to assess particulate air pollution but most results were concerned PM₁₀ alone using fixed monitoring. Therefore, the present study aimed to assess distribution of PM_2.5 in different townships of Yangon, Myanmar. This is the first study to quantify the regional distribution of PM_2.5 in Yangon City.

Methods

The concentration of PM_2.5 was measured using Pocket PM_2.5 Sensor (Yaguchi Electric Co., Ltd., Miyagi, Japan) three times (7:00 h, 13:00 h, 19:00 h) for 15 min per day for 5 days from January 25^th to 29^th in seven townships. Detailed information of eight tracks for PM_2.5 pollution status in different areas with different conditions within Kamayut Township were also collected.

Results

The results showed that in all townships, the highest PM_2.5 concentrations in the morning followed by the evening and the lowest concentrations in the afternoon were observed. Among the seven townships, Hlaingtharyar Township had the highest concentrations (164 ± 52 μg/m³) in the morning and (100 ± 35 μg/m³) in the evening. Data from eight tracks in Kamayut Township also indicated that PM_2.5 concentrations varied between different areas and conditions of the same township at the same time.

Conclusion

Myanmar is one of the few countries that still have to establish national air quality standards. The results obtained from this study are useful for the better understanding of the nature of air pollution linked to PM_2.5. Moreover, the sensor which was used in this study can provide real-time exposure, and this could give more accurate exposure data of the population especially those subpopulations that are highly exposed than fixed station monitoring.

     

Practicalities of mapping PM<Subscript>10</Subscript> and PM<Subscript>2.5</Subscript> concentrations on city-wide scales using a portable particulate monitor

Fine particulate matter is considered to be the most significant ambient air pollutant in terms of potential health impacts. Therefore, it is important that regulators are able to accurately assess the exposure of populations to PM₁₀ and PM_2.5 across municipal areas. We report on the practicalities of using a laser light scattering portable particulate monitor (Turnkey Instruments DustMate), in combination with a GPS, to map PM₁₀ and PM_2.5 concentrations on city-wide scales in Newcastle upon Tyne/Gateshead (UK), during a series of walking surveys. A heated inlet is necessary to remove moisture droplets from the sampled air prior to analysis by the instrument, though this also results in the loss of volatile particulate components, particularly from the PM_2.5 fraction. A co-location calibration study was carried out with a reference urban background Tapered Element Oscillating Micro-Balance/Filter Dynamics Measuring System (TEOM-FDMS) system in Newcastle that is part of the UK’s Automatic Urban and Rural Network (AURN) of air quality monitoring stations. For PM₁₀, orthogonal regression of the DustMate against TEOM-FDMS data gave a slope and intercept of 1.02?±?0.06 and ?3.7?±?1.2, respectively (R ²?=?0.73), whereas for PM_2.5, the respective values were 0.78?±?0.06 and ?0.63?±?0.55 (R ²?=?0.79). These parameters are comparable to literature calibration studies using this technology. There was good agreement between simultaneous samples taken using two DustMate instruments: for PM₁₀, a slope and intercept of 1.05?±?0.03 and 0.36?±?0.5, respectively (R ²?=?0.73), were obtained, whereas for the PM_2.5, the respective values were 0.79?±?0.01 and 0.19?±?0.06 (R ²?=?0.86). Correction factors based on the slope and intercepts obtained from the calibration exercise were applied to raw data collected from the DustMate. An annually-normalised correction procedure was then used to account for different background particulate concentrations on different sampling days. These corrected PM₁₀ and PM_2.5 concentrations and corresponding GPS coordinates were displayed on a base map using Google Fusion Tables and Google Earth Professional. Almost all areas surveyed in Newcastle/Gateshead were well below the EU Air Quality Standards for PM₁₀ and PM_2.5.     

Polycyclic aromatic hydrocarbons in PM<Subscript>10</Subscript>, PM<Subscript>2.5</Subscript> and PM<Subscript>1</Subscript> particle fractions in an urban area

Inhalation of atmospheric polycyclic aromatic hydrocarbons (PAHs) bound to particulate matter can have adverse effects on human health. Particle size plays an important role in assessing health risks. The aim of this study was to compare concentrations of PAHs in different particle fractions. Measurements of PAHs were carried out in Zagreb, the capital of Croatia (~?790,000 inhabitants). The measuring station was located in the northern, residential part of Zagreb, close to a street with modest traffic density. Twenty-four-hour samples of PM₁₀, PM_2.5 and PM₁ particle fraction were collected on quartz filters using a low-volume sampler from about 50 m³ of air. Three fractions were collected from January to December 2013. The analysis was performed using high-performance liquid chromatography (HPLC) with a fluorescence detector and time-programmed changes in excitation and emission. Comparison of PAH content in PM₁₀ and PM_2.5 particle fractions revealed that more than 80% of PAHs measured in winter were bound to the smaller particle fraction (PM_2.5), except for Chry, IP and DahA. In summer, more than 60% of measured PAHs were bound to PM_2.5 particles, except for DahA, while in spring, more than 50% of measured PAHs were bound to PM_2.5 particles, except for Flu, BaP and BbF. Furthermore, comparing PAH content in PM₁ and PM_2.5 fractions, we found that most PAHs were bound to particle fraction PM₁, and the percentage of PAHs in PM₁ was the highest in winter (more than 90%). Factor analysis showed that most of the PAHs bound to PM₁₀, PM_2.5 and PM₁ probably had identical sources in winter, spring and summer (house heating and traffic), and the only significant difference in origin was found in autumn for PAHs bound to PM_2.5 and PM₁ fractions.     

Regulation of fine particulate matter (PM<Subscript>2.5</Subscript>) in the Pacific Rim: perspectives from the APRU Global Health Program

While the development of evidence-based air quality standards for airborne particulate matter (PM) for Europe and North America is well-documented, the standard-setting processes in other regions are less well characterized. Many Pacific Rim economies suffer from severe and worsening air pollution. Particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5) is associated with acute and chronic health effects and is a widely used air quality indicator. This paper reports on PM regulation in selected Pacific Rim economies, focusing on PM_2.5, and provides recommendations on air quality regulation to economies without current standards Through workshops held by the Association of Pacific Rim Universities (APRU) Global Health Program, experts in air pollution from eight universities in eight Pacific Rim economies characterized current PM_2.5 standards and monitoring in their economies, and then collaboratively created recommendations. A great diversity of air pollution exposures exists in the Pacific Rim. While some economies experience low levels of exposure, others have PM levels that are among the highest in the world. The health effects of air pollution are a concern everywhere, but few economies carry out in-depth, local impact assessments and comprehensive air quality monitoring to provide evidence for guidelines and standards. The development of regulations and policies addressing PM_2.5 pollution is urgently needed in many Pacific Rim economies. The international literature provides a robust guide to local risks and should be used, in combination with country-specific population-directed air monitoring, to guide decisions on policies addressing this important global health problem.     

Inhalation exposure of children to indoor PM<Subscript>10</Subscript> and associated metals during river-dust episodes

Three exposure groups (high exposure, low exposure, and control), using six elementary schools in Yulin County, were selected to study the impacts of aeolian river-dust on school children’s exposure to PM₁₀ and associated metals. One classroom and about five school-aged children’s houses for each school were chosen to collect indoor PM₁₀ during the river-dust episodes (RDEs) and non-river-dust episodes (NRDEs). The results indicated that the river-dust episodes had significant impacts on the school-aged children’s exposure to concentrations of PM₁₀ and metals, especially in the high exposure group. For the Ni and Mn metals, the 8-h school exposure concentrations during RDEs were both higher than the standards suggested by the California Environmental Protection Agency. Three interventions for protecting school children from being affected by the river dust during RDEs are suggested in this study. Among the three interventions, children who have a day off of school during RDEs can result in the greatest decrease in the exposure levels of PM₁₀ and associated metals.     

Indoor and outdoor air quality analysis for the city of Nablus in Palestine: seasonal trends of PM<Subscript>10</Subscript>, PM<Subscript>5.0</Subscript>, PM<Subscript>2.5</Subscript>, and PM<Subscript>1.0</Subscript> of residential homes

Nablus city is an important urban and industrial center in the West Bank, Palestine. The topography of the city, combined with multiple sources of air pollution, creates a potential air quality problem that might affect human health. The indoor and outdoor particle concentration distributions of PM₁₀, PM_5.0, PM_2.5, and PM_1.0 were measured using a Grimm aerosol spectrometer from December 2014 to November 2015, at four roadsides and four urban homes in Nablus. The results of the annual averages of PM₁₀ and PM_2.5 concentrations were found to be at least three times higher than that of the European Air Quality Standards both in indoors and outdoors. The difference in the results between both the roadside and the urban areas was attributed to human and industrial activities in Nablus. The results revealed that the highest concentrations of the particulate matters are during summer, especially June and July, in the roadside areas due to heavy industrial activities during these months. The same behavior was noticed for urban areas during summer and due to other human activities. The results of indoor/outdoor (I/O) ratios were found to be less than, but very close to, 1 for both roadside and urban areas in summer and winter months. In winter times, areas with poor ventilation indicated the existence of additional sources of PM within the indoor environments, especially when smoking cigarettes and using fuel-based heaters such as fireplaces gas and kerosene heaters.     

Relationship Between 4-Day Air Mass Back Trajectories and Metallic Components in PM<Subscript>10</Subscript> and PM<Subscript>2.5</Subscript> Particle Fractions in Zagreb Air,Croatia

This paper presents a study on the relationship between trace metal concentrations and the state of the atmosphere at the Croatian EMEP station Puntijarka, Zagreb. PM₁₀ and PM_2.5 particle fractions are hazardous in terms of morbidity and hospitalization due to cardiovascular and respiratory diseases, and in terms of total mortality. In Zagreb, PM₁₀ and PM_2.5 monitoring started on a daily basis at a sampling site located in the northern, residential part of the city. Trace metal concentrations were determined from daily samples. Air mass back trajectories were used to determine particulate air pollution from local and remote sources. The investigation has shown a statistically significant association between air mass back trajectories and metallic air concentration levels.     

Elemental Contribution to the Mass of PM<Subscript>2.5</Subscript> in Guadalajara City,Mexico

The seasonal behavior of the mass of PM_2.5 and its elemental components and their contribution to the mass of the particles is described for two different sites in Guadalajara City. The average mass of the particles for the entire study period at the two sites, Centro and Miravalle (1.3 and 1.8 mg, respectively), showed significant differences (p < 0.05), while differences (p < 0.05) between seasons (rainy and dry season) only occurred at Miravalle. The total elemental contribution to the mass of the particles was 1.97% in Miravalle and 2.05% at Centro, with Iron and Titanium the largest contributors and most abundant elements for both sites. Likewise, the monthly contribution per element with respect to the monthly mass of all elements was estimated. The results revealed that the elements that present the biggest contribution to this mass were Iron, Titanium, Zinc and Magnesium. Iron was the largest contributor at both sites. At Miravalle, the contribution oscillated between 56 and 58% from January to June, while at Centro it oscillated between 55 and 40% for the same period of time.     

Atmospheric PM<Subscript>2.5</Subscript> Mercury in the Metropolitan Area of Mexico City

In this study, atmospheric mercury concentration in airborne particulate matter with an aerodynamic diameter ≤?2.5 µm (PM_2.5) was analyzed by ICP-MS. Samples were collected in the Mexico City Metropolitan Area (MCMA), during 2013, in five locations, Northwest, Northeast (NE), Central, Southwest and Southeast, along three seasons: dry warm, rainy, and dry cold (DC). It can be observed that NE shows the highest mercury concentration (p?<?0.05), where pollution events were identified. The seasonal distribution shows that samples collected during DC present the highest concentration (p?<?0.05). These results are in agreement with the distribution of important mercury industrial sources located in the northern urban area as well with the temperature and wind conditions during 2013. The comparison of data obtained in this work with those of similar previous studies clearly indicates a decrease, between 2006 and 2013, of mercury content in PM_2.5 collected in MCMA.     

Chemical composition of fine particles (PM<Subscript>2.5</Subscript>): water-soluble organic fraction and trace metals

The chemical composition of the atmosphere changes rapidly due to the amount of air pollutants released every day. The aim of this research was to make an exploratory study on the chemical composition (metals and water-soluble organic fraction) of fine particulate matter (PM_2.5) in a region with tropical climate. Multiple sites, with and without the influence of the construction works for the World Cup and Olympic Games, were selected in Rio de Janeiro State, RJ, Brazil. PM_2.5 samples were collected every 6 days from January to December 2011. This is the first PM_2.5 data generated by RJ’s monitoring network. The PM_2.5 annual average concentrations in Rio de Janeiro ranged from 9 to 32 μg m^?3. Metals originated from industrial (Cu, Cd, Pb) and traffic (Cr, Mn, Ni, V, and Zn) emissions, as well as those from natural emissions (Na, K, Ca, Ti, Al, Mg, Fe), were quantified. The concentrations of the metals analyzed ranged from 0.4 to 13,000 ng m^?3. The highest concentrations found were related to metals present in the crust, such as Al (1.6 to 6.7 μg m^?3). In the places where there was the presence of railroad minerals, Ca and Mg appeared in higher concentrations than in the other sites. Fe and PM_2.5 annual and daily average were higher in areas under construction for urban mobility improvements or the Olympic arenas. Even though, the results for Ni, Pb, and Cu were 50% below WHO guidelines. Water-soluble organic carbon (WSOC) concentrations ranged from 0.8 to 4.9 μg m^?3. The highest concentrations (2.4 to 4.9 μg m^?3) were observed in urban areas with intense light vehicle fleet traffic as well as in areas of large industrial influence near highways with intense circulation of heavy vehicles. This is due to the fact that WSOC is mainly formed by the emissions from combustion processes. Studies are needed in order to assess to which extent the WSOC can increase the bioavailability of these and other metals.     

Characteristic and Source of Atmospheric PM<Subscript>10</Subscript>- and PM<Subscript>2.5</Subscript>-bound PAHs in a Typical Metallurgic City Near Yangtze River in China

The characteristics of atmospheric PM₁₀- and PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) were investigated in Tongling city, China. Results showed that the total concentrations of PM₁₀- and PM_2.5-bound PAHs exhibited distinct seasonal and spatial variability. The metallurgic sites showed the highest PAH concentrations, which is mainly attributed to the metallurgic activities (mainly copper ore smelting) and coal combustion as the smelting fuel. The rural area showed the lowest concentrations, but exhibited significant increase from summer to autumn. This seasonal fluctuation is mainly caused by the biomass burning at the sites in the harvest season. The diagnostic ratio indicated that the main PAHs sources were vehicle exhausts, coal combustion and biomass burning. The total BaP equivalent concentration (BAP-TEQ) was found to be maximum at DGS site in winter, whereas it was minimum at BGC site in summer. Risk assessment indicates that residential exposure to PAHs in the industrial area, especially in the winter season, may pose a greater inhalation cancer risk than people living in living area and rural area.     

Characteristics of PM<Subscript>2.5</Subscript> and its chemical constituents in Beijing,Seoul, and Nagasaki

Ambient fine particulate matter (PM_2.5) samples were collected from September 2013 to May 2015 in three cities in East Asian countries (Beijing, China; Seoul, South Korea; and Nagasaki, Japan) in order to analyze the spatiotemporal trends of PM_2.5 chemical constituents including organic matter (OM), elemental carbon (EC), water-soluble inorganic ions (NO₃^?, SO₄^2?, and NH₄⁺), and trace elements. The average PM_2.5 mass concentration were 125?±?6.80 μg m^?3, 44.6?±?0.84 μg m^?3, and 17.4?±?0.37 μg m^?3 in Beijing, Seoul, and Nagasaki, respectively. Higher carbonaceous concentrations were observed during winter in Beijing and Seoul, while higher concentrations were found during spring in Nagasaki. The highest seasonal averages of organic carbon (OC) to EC ratios were found during spring in Beijing, winter in Seoul, and fall in Nagasaki. The concentrations of secondary OC and its ratio to OC were high during fall and winter. For ion species, NO₃^? was dominant in Beijing and Seoul, while SO₄^2? was dominant in Nagasaki. Increased contributions of mobile sources in Beijing and Seoul were observed, with higher NO₃^?/SO₄^2? ratios than those in Nagasaki. Three groups of air masses were found for the three cities using cluster analyses based on 72-h backward trajectories. The cluster from the Bohai economic zone had the highest concentration of PM_2.5 for Beijing. For Seoul, a cluster that originated from the Yellow Sea near an industrial area in Liaoning Province and passed through a highly polluted industrial area in southwestern Seoul had high PM_2.5 concentrations. A long-range transported cluster that originated in and crossed through heavily industrialized areas in China and South Korea for Nagasaki had higher ion species concentrations. The results of this study are useful to identify the current levels of PM_2.5 and its chemical properties to establish a control plan for PM_2.5 for Northeast Asia, including China, South Korea, and Japan.     

Investigating indoor concentrations of PM<Subscript>10</Subscript> in an underground loading dock in Malaysia

Risky air contaminants including PM₁₀ can accumulate inside underground confined loading docks because of the enclosed nature and limited contacts of loading docks with ambient air. Exposure to PM₁₀ can increase morbidity and mortality rates. Hence, this study aimed to investigate and model PM₁₀ concentrations in an underground loading dock located at Kuala Lumpur city center, Malaysia. For this purpose, a real-time air quality monitoring instrument was used for measuring PM₁₀ concentrations for 20 consecutive weeks starting from November 8, 2014. After that, the Statistical Package for Social Sciences (SPSS) software was used to analyze measured PM₁₀ concentrations through series of statistical analyses, whereas MATLAB R2013a was employed for developing prediction models of future PM₁₀ concentrations. Moreover, PM₁₀ temporal variation was examined using time series plots. The results showed that short-term PM₁₀ concentrations did not exceed the Malaysian indoor allowable limit of 150 μg/m³. Despite that, PM₁₀ had 8 % probability of exceedance of WHO standard concentration of 50 μg/m³. This indicates that the occupants will be under the risk of prolonged exposure to PM₁₀ even at low concentrations. The results confirmed a strong correlation between PM₁₀ concentrations and diesel-powered vehicles flow. Contrarily, the flow of gasoline-powered vehicles was poorly correlated. Finally, future daily-averaged PM₁₀ concentrations were predicted for the three weekdays that followed the measurement period using single exponential smoothing. The obtained accuracy was at 70 % of measured PM₁₀ concentrations. Future hourly-averaged PM₁₀ concentrations were estimated using single linear regression with an accuracy of 53 %.     

Assessment of health-based economic costs linked to fine particulate (PM<Subscript>2.5</Subscript>) pollution: a case study of haze during January 2013 in Beijing,China

Beijing is a haze-prone city, which experienced continuous haze during January 2013. The mean fine particulate (PM_2.5) concentrations during January 2013 were 98–228 μg/m³, which were much higher than the mean concentration of 25 μg/m³ over 24 h suggested by the Air Quality Guidelines of the World Health Organization. This event provides a case study to evaluate the effects of extreme haze on health and its subsequent economic costs. We evaluated the health impacts on the Beijing population that were directly attributable to PM_2.5 pollution during the haze. Based on the principle of willingness to pay, we estimated the economic costs associated with these health impacts. This specific haze event in Beijing caused 479 acute deaths from all causes. The economic cost of the deaths attributed to PM_2.5 pollution was ~180 million USD, equivalent to 0.76 % of the gross domestic product (GDP). We also assessed discrepancies in economic costs at the district level in Beijing. Our results revealed that the ratios of economic cost to GDP varied markedly among the 16 districts of Beijing. Such data are relevant to formulating more effective countermeasures to reduce the economic burden associated with severe weather events such as haze.     

Fine aerosol particles (PM<Subscript>1</Subscript>): natural and anthropogenic contributions and health risk assessment

A 1-year-long sampling campaign of sub-micrometric aerosol particles (i.e. PM₁, aerosol particles with an aerodynamic diameter less than 1.0 μm) was performed in southern Italy. PM₁ samples were daily collected and their content in Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn was determined. The trace elements measured accounted on average for about 23.3 % of the total PM₁ mass. Ca, Fe, Na and Al were the most abundant ones representing on average about 86.5 % of the determined PM₁ mass while the relative percentage contributions of the remaining elements were lower than 5.0 % each. Then, by applying a methodological approach based on the combined use of the enrichment factor and the chemical mass closure techniques, the natural and anthropogenic daily contributions to the PM₁ mass were assessed. Results show that natural and anthropogenic sources contributed on average for about 25.6 and 74.4 %, respectively to the PM₁ mass. Finally, a risk analysis was performed in order to evaluate the possible occurrence of adverse human health effects posed by the inhalation of PM₁-bound trace elements measured in the area under study. Results show that the non-carcinogenic effects due to the exposure to Al, Cd, Cr, Mn and Ni in PM₁ were not significant when these elements were considered both individually and simultaneously. Switching to the carcinogenic effects, it was found that the cancer risk associated to Cd, Cr, Ni and Pb in PM₁ was acceptable. Also when the cumulative effect was evaluated, the excess lifetime cancer risk values found were lower than the acceptable limit indicating that 9 children in one million inhabitants and 37 adults in one million inhabitants might get cancer by the inhalation of PM₁-bound Cd, Cr, Ni and Pb over lifetime.     

Parameter and model uncertainty in a life-table model for fine particles (PM<Subscript>2.5</Subscript>): a statistical modeling study

Background  

The estimation of health impacts involves often uncertain input variables and assumptions which have to be incorporated into the model structure. These uncertainties may have significant effects on the results obtained with model, and, thus, on decision making. Fine particles (PM_2.5) are believed to cause major health impacts, and, consequently, uncertainties in their health impact assessment have clear relevance to policy-making. We studied the effects of various uncertain input variables by building a life-table model for fine particles.     

Seasonal variation and health risk assessment of atmospheric PM<Subscript>2.5</Subscript>-bound polycyclic aromatic hydrocarbons in a classic agglomeration industrial city,central China

Sixty atmospheric sample concentrations of PM_2.5 and polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 were analyzed in distinct seasonal variations from a classic agglomeration industrial city. The concentrations of PM_2.5 ranged from 6.96 to 260.06 μg/m³ with an average of 177.05 μg/m³. Only 38% of the sampling days were superior to the 24-h limit value (75 μg/m³) of ambient air quality standards (AAQs), and the samples from autumn and winter exceeded the limit value. The total PAHs ranged from 1.51 to 44.51 ng/m³ with an average of 10.65 ng/m³. The highest and lowest concentrations of total PAHs appeared in winter and summer with averages of 22.56 and 4.03 ng/m³, respectively. Correlation analysis revealed that high-molecular-weight PAHs (HMW-PAHs) (4-, 5-, 6-ring PAHs) were significantly and negatively correlated with temperature and water-soluble total organic carbon (WTOC), and significantly correlated with water-soluble total nitrogen (WTN). The 4-, 5- and 6-ring PAHs were dominant, especially those of 4-ring PAHs, which were above 30% of the total PAHs in each season. Source apportionment indicated that PM_2.5-bound PAHs in Huangshi were mainly derived from pyrogenic source, vehicle exhaust, coal combustion, and biomass burning. Incremental lifetime cancer risks (ILCRs) showed no potential carcinogenic risk from the PM_2.5-bound BaP-eq. ILCRs in winter were the highest, and the risks for adults were approximately an order of magnitude higher than those for children.     

Acidic Anions in PM<Subscript>10</Subscript> Particle Fraction in Zagreb Air,Croatia

This paper presents the results of 7 years continuous measurement of acidic anions chlorides, nitrates, and sulphates in PM₁₀ particle fraction in the city of Zagreb, Croatia. The mean annual mass concentrations of the investigated anions in PM₁₀ particle fraction varied from 0.28 to 0.95 μg/m³ for chlorides, from 3.21 to 7.87 μg/m³ for nitrates and from 3.98 to 9.71 μg/m³ for sulphates. The concentration levels of all measured anions showed significant seasonal differences. The most contributing to the PM₁₀ mass were sulphates, then nitrates, and then chlorides. The mobile source emission was an important contributor to particle mass.     

Identification of concentrations and sources of PM<Subscript>2.5</Subscript>-bound PAHs in North China during haze episodes in 2013

An analysis of 12 polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 (particulate matter with a diameter smaller than 2.5 microns) samples collected at Yucheng, Shandong, in June 2013 was conducted to determine the concentrations, composition, sources, and associated cancer risk. The results revealed that the average PAH concentration was higher during haze episodes (28.28?±?8.35 ng m^?3) when compared to non-haze episodes (23.68?±?4.17 ng m^?3), and diagnostic ratio and principal component analyses indicate that the predominant sources of PAHs were from fossil fuel and coal combustion, likely from vehicle emissions and industrial sources and biomass burning. Coal combustion and biomass burning contributed significantly more during haze episodes, whereas liquid fossil fuel combustion (e.g. petroleum) was the dominant contributor during the non-haze periods. In addition, back-trajectory calculations revealed that the long-distance transport of air masses from regions with industrial pollution and biomass burning contributed significantly to the concentrations of PAHs in the region. The concentration of high molecular weight PAHs (HMW-PAHs) increased from 62.3 % under non-haze conditions to 67.9 % during the haze periods. The benzo[a]pyrene-equivalent carcinogenic potency value during haze episodes was higher (7.09 ng m^?3) than that during non-haze (5.64 ng m^?3) periods and adults over 30 years old in the Shandong province are at an increased risk of cancer from PAHs.