Mass Concentrations Of PM2 Research Articles

Establishing Correlation between Cruise Ship Activities and Ambient PM Concentrations in the Kotor Bay Area Using a Low-Cost Sensor Network

The analysis of cruise ships is focusing on port areas where they may represent a significant source of anthropogenic emissions. In order to determine the correlation between cruise ship activities (hoteling and maneuvering) in ports with the ambient concentration of pollutants associated with marine diesel fuel combustion, the low-cost sensors are finding their market share due to lower prices compared to the referent ones. In this study, a network of four low-cost PM sensors was used to determine the correlation between ambient PM2.5 and PM10 mass concentrations with cruise ship activities in the Kotor Bay area during 27 days in the peak summer season, with a 10-min resolution. Recorded data and the Openair model were used to investigate the potential relationship between cruise ship operations and temporal fluctuations in PM concentrations in the ambient air. Additionally, an Tier 3 methodology developed through the European Monitoring and Evaluation Programme of the European Environmental Agency (EMEP/EEA) was applied in order to estimate the total cruise ship PM emissions. The study has shown that weather conditions play a significant role in local PM concentrations, so that, with predominant ENE wind directions, the west side of the Bay experienced on average higher concentrations of both PM2.5 and PM10. Rain precipitation and higher winds tend to decrease rapidly ambient PM concentrations. Higher PM levels are associated mainly with lower wind speeds and the inflows from neighboring berths/anchorages. During the maneuvering (arrival and departure) of cruise ships, higher spikes in PM values were detected, being more visible for PM10 than PM2.5. A significant correlation between daily average PM concentrations and cruise ships’ daily estimated PM emission was not found. As a result, higher temporal resolution demonstrated a stronger correlation.

Impact of PM2.5 and PM10 Emissions on Changes of Their Concentration Levels in Lithuania: A Case Study

Due to negative effects on human health and visibility, atmospheric particulate matter (PM) is a prioritized contaminant for urban air pollution management. Over the past few decades, managing emissions have been a top priority. This paper investigated PM national inventory data and mass concentration trends for Lithuania. This analysis considers primary (sum of filterable and condensable) PM2.5 and PM10 emissions from point, mobile on-road and off-road, industry, agriculture, and waste sectors. In this study, by examining both the emissions and the mass concentrations of PM10, the effects of emissions decreasing with a concentration decrease were revealed. The slower decreasing tendency of PM10 and BC (0.03 Gg/year) than that of PM2.5 (0.1 Gg/year) should be noted. Furthermore, the correlation analysis also finds that the increase in PM10 from stationary and mobile combustion sources is closely related to the increase in the contribution to the pollution level.

Impact of the MEDEA exposure-reduction strategies on indoor air quality during desert dust storms

Abstract Background Desert dust storms (DDS) impact the Mediterranean basin heavily, particularly in the context of climate change, reduced precipitation and increasing desertification. There is a pressing need to develop policies protecting EU citizens’ health from DDS. While Public Health authorities in affected regions commonly issue warnings, the effectiveness of recommendations to reduce exposure has not been documented. Methods This work is part of the wider “MEDEA” intervention studies, co-funded by LIFE 2016 Programme. Among other outcomes, the studies examined the effectiveness of an indoor exposure-reduction intervention (i.e., decrease home ventilation and use of air cleaners) across homes of asthmatic schoolchildren and individuals with atrial fibrillation in Cyprus. Participants were randomized to either a control or indoor intervention group. The assessment took place in a sample of participants’ homes, during 2019 and 2021, with the collection of indoor and outdoor PM10 and PM2.5 samples, which were analyzed for mass and elemental concentrations. Results Indoor PM2.5 and PM10 mass and elements concentrations were significantly lower in the indoor intervention group compared to the control group, both during days with no dust (e.g., 55% and 48% reduction for PM2.5 and PM10, respectively) and days with desert dust (PM2.5: 47% and PM10: 40% reduction). In addition, the infiltration of PM2.5 and PM10 particles from the outdoor to the indoor air was significantly lower in the intervention vs. the control group (PM2.5: -55%, 95% CI: -42%, -65%; PM10: -41%, 95% CI: -61%, -12%). Conclusions The study assessed a realistic exposure-reduction strategy and provided first-time evidence that closing doors and windows along with air cleaners can reduce indoor exposure to DDS particles. This evidence can further inform decision-making and strategic planning for population-level mitigation of DDS health effects in Mediterranean Europe. Key messages

Characterization of Fe-containing particles in Chengdu, southwest China, using single-particle aerosol mass spectrometry

Single-particle aerosol mass spectrometry was used to study the characteristics of Fe-containing particles during winter in Chengdu, southwest China. The mass concentrations of PM2.5 and PM10 during the study period were 64 ± 38 and 89 ± 49 µg/m3, respectively, and NO2 and particulate matter were high compared with most other regions of China. The Fe-containing particles were divided into seven categories with different mass spectra, sources and aging characteristics. The highest contribution was from Fe mixed with carbonaceous components (Fe-C, 23.1%) particles. Fe was more mixed with sulfate than nitrate and therefore the contribution of Fe mixed with sulfate (Fe-S, 20.7%) particles was higher than that of Fe mixed with nitrate (Fe-N, 12.5%) particles. The contributions from Fe-containing particles related to primary combustion were high in the small particle size range, whereas aged Fe-containing particles and dust-related particles were mostly found in the coarse particle size range. The air masses mainly originated from the west and east of Chengdu, and the corresponding PM2.5 concentrations were 79 ± 36 and 55 ± 36 µg/m3, respectively. The west and east air masses showed stronger contributions of Fe-containing particles related to biomass burning (Fe-B) and fossil fuel combustion (Fe-C and Fe-S) particles, respectively. The southwest area contributed the most Fe-containing particles. Future assessments of the effects of Fe-containing particles during heavy pollution period should pay more attention to Fe-C and Fe-S particles. Emission-reduction of Fe-containing particles should consider both local emissions and short-distance transmission from the surrounding areas.

Exploring the Mass Concentration of Particulate Matter and Its Relationship with Meteorological Parameters in the Hindu-Kush Range

Particulate matter (PM) is among the deadliest air pollutants due to its negative health impacts and environmental harm. This study reports on monthly and seasonal concentrations of PM10, PM2.5, and PM1, along with their ratios. Twelve-day samples were collected once a month in Mingora city (Swat, Pakistan) from January to December 2019 using a low volume sampler. Maximum average mass concentrations of PM10, PM2.5, and PM1 were recorded in December having values of 78, 56, and 32 μg m−3, respectively. Minimum average values for PM10 (44 μg m−3) and PM2.5 (25.1 μg m−3) were recorded in April, while the lowest PM1 (11 μg m−3) was recorded in August. In comparison to other months, the maximum average mass concentrations were 1.77 times (PM10), 2.23 times (PM2.5), and 2.9 times (PM1) higher in December. During the winter season, average mass concentrations remained high. Substantial correlation coefficients of 0.92, 0.79, and 0.75 were recorded between PM10 and PM2.5, PM2.5 and PM1, and PM2.5 and PM1, respectively. The overall average ratios PM2.5: PM10, PM1: PM2.5, and PM1: PM10 were 68.3, 52.6, and 35.4%, respectively. A moderate negative correlation of PM10, PM2.5, and PM1 with wind speed (−0.34, −0.39, and −0.41), a strong negative correlation with temperature (−0.69, −0.71, and −0.74) and rainfall (−0.63, −0.61, and −0.59), and a weak relationship with relative humidity (−0.32, −0.1, and −0.02) were recorded.

CONCENTRATION OF FINE PARTICULATE MATTER (PM\(_{2.5}\)) AND BLACK CARBON (BC) IN AEROSOL SAMPLES IN AL-ZUBAIRY AREA IN SANA’A, YEMEN

This research aims to study the air pollution due to fine Particulate Matter of radius less than 2.5µm (PM2.5) and Black Carbon concentration (BC) in air samples. Aerosol PM2.5 samples were collected from the rooftop of the National Oncology Center site in Al-Zubairy area in Sana’a Yemen. A Microprocessor Controlled Aerosol Sampling device ISAP1050e (Gerhard Schulze Automation Engineering, Germany company) was used to collect samples. The mass concentration of PM2.5 of collected samples ranged from 14.27 to 159.09 µg/m3 with an average of 32.66µg/m3. The PM2.5 results were compared with the World Health Organization (WHO) 2005 guideline of PM2.5 concentration in air. Statistical analysis showed a positive correlation between PM2.5 concentrations and temperature for both fall and summer samples. However, analysis showed a positive correlation between PM2.5 concentrations and relative humidity for fall samples and a negative correlation for summer samples. The black carbon (BC) concentrations in PM2.5 samples were measured using a Smoke Stain Reflectometer (SSR) device. The BC concentration ranged from 1.84 to 3.90 µg/m3 with an average of 2.90 µg/m3. The BC results were compared with some international reported results. The Air Quality Index (AQI) of 78.95% of PM2.5 concentrations was higher than the standard limit (AQI < 100) developed by the United States Environmental Protection Agency (EPA).

CHARACTERIZATION OF SIZE-RESOLVED PARTICLES AND CHEMICAL COMPOSITION AT TWO ELEMENTARY SCHOOLS IN HANOI, VIETNAM

Indoor and outdoor ultrafine, accumulation mode, and coarse fractions collected at two elementaryschools (S1 and S2) in Hanoi capital, Vietnam were characterized in terms of mass, numberconcentrations, particle morphology, and chemical composition to assess the indoor air quality atthe examined schools. The sampling campaigns were performed simultaneously indoors andoutdoors for three consecutive weeks at each school. Indoor average concentrations of CO2 and COat both schools were below the limit values recommended by the American Society of Heating,Refrigerating and Air-Conditioning Engineers (1000 ppm for CO2) and World Health Organization(7 mg/m3 for CO). Indoor mass concentrations of PM10 and CO2 at S1 and S2 were stronglyinfluenced by the presence of children and their activities indoors whereas the numberconcentration of particlesseemed not to be impacted by occupants’ activities. Water-soluble ionscommonly presented unimodal distribution for indoor and outdoor airborne particles at S1 and S2,which accounted for typically a proportion of around 3.5-5% of the total mass of particles. Oxygen(O) was the most abundant element in all fractions, followed by carbon (C) for indoor and outdoorparticles.

Triggering of ST-elevation myocardial infarction by ultrafine particles in New York: Changes following Tier 3 vehicle introduction

BackgroundPreviously, we found increased rates of ST-elevation myocardial infarction (STEMI) associated with increased ultrafine particle (UFP; <100 nm) concentrations in the previous few hours in Rochester, New York. Relative rates were higher after air quality policies and a recession reduced pollutant concentrations (2014–2016 versus 2005–2013), suggesting PM composition had changed and the same PM mass concentration had become more toxic. Tier 3 light duty vehicles, which should produce less primary organic aerosols and oxidizable gaseous compounds, likely making PM less toxic, were introduced in 2017. Thus, we hypothesized we would observe a lower relative STEMI rate in 2017–2019 than 2014–2016. MethodsUsing STEMI events treated at the University of Rochester Medical Center (2014–2019), UFP and other pollutants measured in Rochester, a case-crossover design, and conditional logistic regression models, we estimated the rate of STEMI associated with increased UFP and other pollutants in the previous hours and days in the 2014–2016 and 2017–2019 periods. ResultsAn increased rate of STEMI was associated with each 3111 particles/cm3 increase in UFP concentration in the previous hour in 2014–2016 (lag hour 0: OR = 1.22; 95% CI = 1.06, 1.39), but not in 2017–2019 (OR = 0.94; 95% CI = 0.80, 1.10). There were similar patterns for black carbon, UFP11–50nm, and UFP51–100nm. In contrast, increased rates of STEMI were associated with each 0.6 ppb increase in SO2 concentration in the previous 120 h in both periods (2014–2016: OR = 1.26, 95% CI = 1.03, 1.55; 2017–2019: OR = 1.21, 95% CI = 0.87, 1.68). ConclusionsGreater rates of STEMI were associated with short term increases in concentrations of UFP and other motor vehicle related pollutants before Tier 3 introduction (2014–2016), but not afterwards (2017–2019). This change may be due to changes in PM composition after Tier 3 introduction, as well as to increased exposure misclassification and greater underestimation of effects from 2017 to 2019.

Characterization of indoor and ambient air quality in modern commercial and recreational complex buildings in Hanoi

The paper provides new information on the correlation between indoor and ambient air quality in selected commercial and recreational buildings, representing a cross-section of metropolitan building complexes in Hanoi, Vietnam. Air sampling carried out simultaneously at fixed locations within the case study directed the varying behavior across different zones and thus highlighted the relationship between parking basements, commercial floors, and ambient air sites. The fractions of coarse and fine particles were analyzed to identify the associated emission sources on a short-term basis. The elevated 8-h average levels of CO in underground parking zones (11–22 mg/m3) were significantly higher than those measured on commercial floors (0.5–0.9 mg/m3) and relatively ambient air (0.8–1 mg/m3) and exceeded the recommended exposure limit of 10 mg/m3 in the corresponding guidelines. Short-term averages of SO2 mass concentration (112–225 μg/m3) remained below the limits of 500 μg/m3 concerning health exposure in existing standards. The correlation of daily NO2 patterns was analyzed accordingly in relation to the operation of the individual building, the central ventilation mechanism, and the penetration of outside air, which is usually conditioned by traffic emission. The mass concentrations of PM10 and PM2.5 measured outdoors (21–32 μg/m3 and 12–14 μg/m3) and in parking basements (28–67 μg/m3 and 15–27 μg/m3) were generally higher than those recorded indoors at ground levels (1–29 μg/m3 and 1–20 μg/m3), frequently reaching the reference exposure values (15 μg/m3 and 5 μg/m3) for public health concerns. The determined levels and profiles of benzene, toluene, ethylbenzene, (m + p)-xylene, and o-xylene corresponding to the relative ratios of T/B and X/E revealed the responsible emissions from gasoline-fueled vehicles in parking basements and the influence of associated local traffic.

Representativeness of the particulate matter pollution assessed by an official monitoring station of air quality in Santiago, Chile: projection to human health

Santiago, capital city of Chile, presents air pollution problems for decades mainly by particulate matter, which significantly affects population health, despite national authority efforts to improve air quality. Different properties of the particulate matter (PM10, PM2.5 and PM1 fractions, particle surface and number) were measured with an optical spectrometer. The sampling was done during spring 2019 at different sites within the official representative area of Independencia monitoring station (ORMS-IS). The results of this study evidence large variations in PM mass concentration at small-scale areas within the ORMS-IS representative zone, which reports the same value for the total area. Results from PM properties such as PM1, particle number and particle surface distribution show that these properties should be incorporated in regular monitoring in order to improve the understanding of the effects of these factors on human health. The use of urban-climate canopy-layer models in a portion of the sampled area around the monitoring station demonstrates the influence of street geometry, building densities and vegetation covers on wind velocity and direction. These factors, consequently, have an effect on the potential for air pollutants concentrations. The results of this study evidence the existence of hot spots of PM pollution within the area of representativeness of the ORMS-IS. This result is relevant from the point of view of human health and contributes to improve the effectiveness of emission reduction policies.

Characteristics and Impact Factors of Number Concentration of Primary Biological Aerosol Particles in Beijing

Primary biological aerosol particles (PBAP) are an important part of ambient aerosols. Both living and dead organisms not only influence human health and air quality but also play important roles in regulating certain atmospheric processes and affect the hydrological cycle and climate change. In this study, flow cytometry (FCM) was utilized in combination with the simultaneous use of permeant (SYBR Green I) and impermeant (propidium iodide, PI) nucleic acid fluorescent staining to detect and quantify the viable and dead airborne biological particles. At the same time, based on this method, the dead/viable PBAP in a Beijing urban area was detected and quantified. Moreover, the influence of environmental factors on the concentrations of primary biological aerosol particles was illuminated. The results showed that the media number concentration of dead and alive PBAP in the Beijing urban area during summer (1.03×106 m-3 and 7.43×105 m-3, respectively) were higher than those during winter (7.34×105 m-3and 6.18×105 m-3, respectively). Statistical analysis showed that there was no significant correlation between PBAP number concentration and environmental factors, i.e., meteorological conditions and air quality, showing a weak positive correlation with temperature and humidity and weak negative correlations with O3, maximum wind speed, and sunshine duration. The number concentration of PBAP was weakly correlated with the mass concentration of PM2.5 but positively correlated with that of coarse particulate matter (PM2.5-10). Both stable weather and dust transport could increase the number concentration of PBAP in Beijing.

Highly time-resolved measurements of elements in PM2.5 in Changzhou, China: Temporal variation, source identification and health risks

The temporal variation, sources, and health risks of elemental composition in fine particles (PM2.5) were explored using online measurements of 19 elements with a time resolution of 1 h at an urban location in Changzhou, China, from December 10, 2020 to March 31, 2021. The mass concentration of PM2.5 was 50.1 ± 32.6 μg m−3, with a range of 3–218 μg m−3. The total concentration of 19 elements (2568 ± 1839 ng m−3) accounted for 5.1 % of PM2.5 mass concentration. S, Cl, Si, and Fe were the dominant elementary species, accounting for 90 % of total element mass concentrations during the whole campaign. Positive matrix factorization (PMF) model was applied to identify the major emission sources of elements in PM2.5. Seven factors, named secondary sulfate mixed with coal combustion, Cl-rich, traffic, iron and steel industry, soil dust, fireworks, and shipping, were identified. The major sources for elements were iron and steel industry, followed by soil dust and secondary sulfate mixed with coal combustion, explaining 32.0 %, 23.5 % and 16.7 % of the total source contribution, respectively. The total hazard index (HI) of elements was 3.01 for children and 1.18 for adults, much greater than the admissible level (HI = 1). The total carcinogenic risk (CR) in Changzhou was estimated to be 5.87 × 10−5, which was above the acceptable CR level (1 × 10−6). Among the calculated metal elements, Cr, Co and As have higher carcinogenic risk, and Co was found to trigger the highest noncarcinogenic risk to Children. Our results indicate that industrial emission is the dominant CR contributor, emphasizing the necessity for stringent regulation of industry sources. Overall, our study provides useful information for policymakers to reduce emissions and health risks from elements in the Yangtze River Delta region.

Elucidating the Chemical Compositions and Source Apportionment of Multi-Size Atmospheric Particulate (PM10, PM2.5 and PM1) in 2019–2020 Winter in Xinxiang, North China

The pollution characteristics of multi-size atmospheric particulates in Xinxiang, which was one of the most polluted cities across China, are still unclear even through air quality in Xinxiang has been improved in recent years. PM10, PM2.5, and PM1 samples were synchronously collected from 21 December 2019 to 17 January 2020 to explore pollution levels and reveal sources of PM in Xinxiang. The average mass concentrations of PM10, PM2.5, and PM1 were as high as 155.53 μg m−3, 120.07 μg m−3, and 85.64 μg m−3 during the observation period, respectively. Almost all of the chemical compositions in PM10, PM2.5 and PM1 increased continuously and obviously with the aggravation of the pollution level. Compared with the clean period, the enhancement of sulfate (23–27%) in PM was obvious higher than nitrate (19–22%) during the pollution period, which demonstrated that sulfate was the main contributor to the high concentration of PM in this study. Similar source distributions for PM10, PM2.5, and PM1 were also found, including traffic source, combustion source, secondary aerosols, industrial source, and fugitive dust, by using the positive matrix factorization (PMF) model. Furthermore, the contributions of the combustion source and secondary aerosol were found to be higher in smaller particles (PM2.5 and PM1), while the contribution of fugitive dust was higher in PM10. Moreover, dust and sand were entrained by air masses from the northwest that increased the contribution of dust in PM at the observation site. The potential source contribution function (PSCF) analysis illustrated that regional emission sources in northern and eastern Xinxiang might be important potential contributors to PM pollution in Xinxiang.

Evaluation of aerosol-spectrometer based PM2.5 and PM10 mass concentration measurement using ambient-like model aerosols in the laboratory

We have evaluated the PM10 and PM2.5 measurement using a Grimm 11-D optical particle size spectrometer (OPSS) with ambient-like aerosols generated in a laboratory. The ambient-like model aerosols include fresh soot, aged soot, ammonium sulfate, ammonium nitrate and Arizona Road Dust (ARD) particles. The mass concentration (MC) of test aerosols has been computed from the particle counts, equivalent particle volume and particle effective density using a proposed method. The expanded measurement uncertainties for the computed MC are estimated to be 27–36%, with detailed uncertainty analysis. The deviation of the computed MC from the reference gravimetric values is below 20% for MC levels from 29 to 1584 µg/m3. The computed MC agree with the reference MC within their measurement uncertainties. The underestimation and overestimation of the computed MC at various MC levels have been explained based on OPSS sizing errors related to the light-scattering and absorption property of the model aerosols. The proposed MC computation method is useful to evaluate the accuracy of OPSS in PM10 and PM2.5 measurement with the lab-generated model aerosols. This method can also be used to compare the performance of various OPSS-based PM monitors via inter-laboratory comparisons.

Chemical components of PM2.5 in different seasons in Harbin, China

The seasonal characteristics of fine particulate matter (PM2.5) were investigated from October 2020 to April 2021 (spreading fall, winter and spring) in Harbin, a city located in northeast China. The mass concentrations of PM2.5 in winter were significantly higher than those in fall and spring. Moreover, our results indicated that various aerosol species had obvious seasonality. The proportions of secondary components were higher in winter than other two seasons. In contrast, the ratios of nitrate to sulfate (NO3−/SO42−) showed lower levels in winter, which was because both the ratios of nitrogen dioxide to sulfur dioxide (NO2/SO2) and the ratios of nitrogen oxidation ratio to sulfur oxidation ratio (NOR/SOR) exhibited lower values in winter than in fall and spring. With PM2.5 increased, the NO3−/SO42− ratios showed increasing trends in all three seasons, which was mainly attributed to the increase of NOR/SOR ratios in fall and spring, and the increase of both NO2/SO2 and NOR/SOR ratios in winter. This result highlighted that nitrate was more important than sulfate as a driver for the growth of PM2.5 during the period of heavy air pollution. Additionally, the sources of organic aerosol (OA) in different seasons were also distinctly different. Overall, the sum of biomass burning OA (BBOA) and secondary OA (SOA) contributed >70% of OA in three seasons. The fractional contributions of BBOA to total OA, notably, exhibited higher levels in fall and spring, because of intensive open agricultural fires. The SOA fractions in OA were larger in winter, likely due to higher relative humidity which facilitated the secondary formation. A large increase in the proportions of BBOA was observed during polluted days in fall and spring compared to clean days. In comparison, during heavily-polluted periods, secondary formation made a dominant contribution to organic matter in winter.

Characteristics and Source Analysis of PM1 in a Typical Steel-Industry City, Southwest China

Mining activities have led to severe air pollution problems while they make great contributions to economic construction. Therefore, as a typical steel-industry city in southwest China, Panzhihua, its air pollution has received extensive attention. The characteristics of PM1 in different functional areas of Panzhihua from 2018 to 2019, and the changes of its microstructure and potentially toxic elements (PTEs) and the sources of PM1 were analyzed. The results showed that the mass concentrations of PM1 in the heavy pollution area of Nongnongping (NNP) and the complex industrial pollution area of Hemenkou (HMK) were 12.12–145.30 μg/m3 and 14.38–67.02 μg/m3, respectively. Seasonal PM1 mass concentrations in the two functional areas could be arranged in the following order: winter &gt; autumn &gt; spring &gt; summer. The main particle types in PM1 were fly ash, soot, sulphate particles, aluminosilicate particles and metal particles. Potential sources of PM1 in Panzhihua included coal burning, biomass combustion, automobile exhaust and mining activities. At the same time, the average concentrations of PTEs at NNP were also higher than those at HMK because of smelting activities. Enrichment factor analysis showed that most of the PTEs came from human sources. The results could provide theoretical guidance for environmental management.

Trend in Particulate air pollutants in Visakhapatnam city for 2018-2020: A case study

Rapid industrialization aided by urbanization led to severe air pollution in Visakhapatnam city, withprominent pollutant being particulate matter (PM10). This paper aims to anlyse the trend in particulatematter over a three year period, 2018-20. The results indicate high mass concentrations of PM10 in winter,mostly exceeding NAAQS limits. Clearer air quality is observed in summer and monsoon seasons. Thecity’s bowl-shaped area promotes the accumulation of pollution in winter.

On-line measurement of ultralow mass concentration particulate based on light scattering coupled with beta ray attenuation method

Light scattering method is the most commonly used method for on-line measurement of ultralow particulate matter mass concentration. However, when the particle characteristics change, the effectiveness of the empirical relationship decreases, which would lead to a sizeable deviation. To accurately measure the mass concentration of particulate matter in real-time, a coupling measurement idea of light scattering and beta-ray attenuation is proposed. The beta-ray attenuation is little affected by particle properties and accurately reflects the average PM mass concentration in the measured period. The single calibration method (M1), periodic calibration method (M2), average calibration method (M3), and asymmetric factor calibration method (M4) are formed based on the coupling idea. The results of all methods are perfect when the particle size is unchanged. However, when the particle sizes fluctuate frequently, the results of M1, M2, and M3 deviate seriously from the actual value, and the applicable working conditions have limitations. The results of M4 are in good agreement with the actual value, and the effectiveness is not limited by the particle size. Finally, the prototype based on experimental exploration was developed and had been continuously operated for more than 528 h at a 1000 MW unit of a coal-fired power plant.

Evaluation of vertical and horizontal distribution of particulate matter near an urban roadway using an unmanned aerial vehicle.

Measurement of traffic emissions has gained a lot of interest in recent times due to its contribution to urban pollution. This paper reports the outcome from an unmanned aerial vehicle (UAV) based measurement of PM concentration near an urban roadway at Kolkata, India. A total of 54 flights were carried out for simultaneous measurements of PM1, PM2.5 and PM10 mass concentration and meteorological parameters in vertical as well as in horizontal direction. Results for the vertical flight up to 100 m showed that the PM1, PM2.5 and PM10 concentrations at higher altitudes are less (mean; 24.6, 39.9 and 103.8 μg m-3) compared to the respective ground level concentrations (mean; 26.3, 50.4 and 201.9 μg m-3). For all the three particle sizes, the majority of the cases of higher PM concentration at higher altitudes happened during the evening flight. Low mixing height and low wind speed are suggested to be the reasons for the poor dispersion of pollutants in the evening. While there was a 7-10% fall of fine particles (PM1 and PM2.5) mass concentrations up to 90 m away from the road, no trend could be seen for PM10. The random forest model to predict the UAV/Ground concentration ratio showed high accuracy (R2 = 0.82-0.95) for all three particle sizes. This is an important finding from this study, which shows how UAV measurement data can be used to generate models that can predict the higher altitude concentrations from the ground based measurements.

Characterizing a Heavy Dust Storm Event in 2021: Transport, Optical Properties and Impact, Using Multi-Sensor Data Observed in Jinan, China

On 15 March 2021, the strongest sandstorm of the last 10 years occurred in China. The MODIS, MPL lidar, EDM 180, ADI 2080 and Meteorological observation instruments were used to observe the dust in Jinan, China, while the HYSPLIT model was also employed to find the source. It was found that the dust originated from Mongolia and the Gobi desert and was transported to Jinan at night on 14th March, lasting until the 18th. Multi-layer dust was observed, of which the dust below the height of 1 km was strongest with the VDR about 0.2 and the maximum extinction coefficient up to 3 km−1. The values of AOD and AE were greater than 2 and less than 0.25, respectively. The mass concentrations of PM10 and PM2.5 increased rapidly, and were up to 573 µg/m3 and 3406 µg/m3, respectively. Additionally, the mass concentration ratio decreased rapidly, with a minimum of 17%. The particle size of the dust was mainly distributed between 0.58–6.50 micros due to larger particles increasing dramatically; simultaneously, both the proportion and the value for calcium ions in PM2.5 went up. The dust had an obvious impact on the vertical structure of the air temperature, resulting in occurrence of a strong inversion layer.