Particulate Matter Air Research Articles

Inflammation Describes and Explains the Adverse Effects of Aerosol Optical Depth-Particulate Matter on Cardiovascular Outcomes: A Literature Review Since 2012

The success of remote sensing methodology to accurately estimate ambient particulate matter (PM) on the earth’s surface has resulted in the increased use of aerosol optical depth (AOD) AOD-PM 10 , AOD-PM 2.5 and AOD-PM 1 concentration level fused surfaces in cardiovascular epidemiologic and hypothesis-testing of inflammatory physiologic studies. Uniform space-time AOD-PM concentration level fused surfaces have been used as proxies for ambient PM monitor measurements in economically developed and developing counties as well as in densely populated urban regions with on-the-ground ambient PM monitors and in sparsely populated rural areas without ambient PM air monitors to determine the contribution of PM exposure to the subsequent occurrence of cardiovascular chronic diseases and circulatory-related adverse health outcomes. Since 2012, 45 published studies have evaluated the association between increased AOD-PM concentration level readings and adverse cardiovascular outcomes. Fifteen surveillance studies used inflammation as a descriptive physiologic mechanism and another nine publications mentioned another description. In contrast, another 20 investigations have used the inflammatory physiologic mechanism to explain how AOD-PM exposure changes the cardiovascular system and other organs connected to the cardiovascular system through the circulatory system and one report referred to some other explanation. The full extent of the adverse effects of AOD-PM exposure on the cardiovascular system only becomes evident when cardiovascular and other pathophysiological changes are also considered and evaluated. This review paper aims to demonstrate why AOD-PM and cardiovascular system studies are a new and useful source of information about how ambient PM exposure adversely impacts the cardiovascular system in diverse populations in different countries.

Sources, chemical components, and toxicological responses of size segregated urban air PM samples in high air pollution season in Guangzhou, China

The sources, sizes, components, and toxicological responses of particulate matter (PM) have demonstrated remarkable spatiotemporal variability. However, associations between components, sources, and toxicological effects in different-sized PM remain unclear. The purposes of this study were to 1) determine the sources of PM chemical components, 2) investigate the associations between components and toxicology of PM from Guangzhou high air pollution season. We collected size-segregated PM samples (PM10–2.5, PM2.5–1, PM1–0.2, PM0.2) from December 2017 to March 2018 in Guangzhou. PM sources and components were analyzed. RAW264.7 mouse macrophages were treated with PM samples for 24 h followed by measurements of toxicological responses. The concentrations of PM10–2.5 and PM1–0.2 were relatively high in all samples. Water-soluble ions and PAHs were more abundant in smaller-diameter PM, while metallic elements were more enriched in larger-diameter PM. Traffic exhaust, soil dust, and biomass burning/petrochemical were the most important sources of PAHs, metals and ions, respectively. The main contributions to PM were soil dust, coal combustion, and biomass burning/petrochemical. Exposure to PM10–2.5 induced the most significant reduction of cell mitochondrial activity, oxidative stress and inflammatory response, whereas DNA damage, an increase of Sub G1/G0 population, and impaired cell membrane integrity were most evident with PM1–0.2 exposure. There were moderate or strong correlations between most single chemicals and almost all toxicological endpoints as well as between various toxicological outcomes. Our findings highlight those various size-segregated PM-induced toxicological effects in cells, and identify chemical components and sources of PM that play the key role in adverse intracellular responses. Although fine and ultrafine PM have attracted much attention, the inflammatory damage caused by coarse PM cannot be ignored.

Exercise-induced bronchoconstriction is associated with air humidity and particulate matter concentration in preschool children.

Long-term exposure to air pollution is connected to asthma morbidity in children. Exercise-induced bronchoconstriction (EIB) is common in asthma, and the free running test outdoors is an important method for diagnosing asthma in children. It is not known whether momentary air pollution exposure affects the results of outdoor exercise tests in children. We analyzed all reliable exercise challenge tests with impulse oscillometry in children (n = 868) performed between January 2012 and April 2015 at Tampere University Hospital. Pollutant concentrations (PM2.5 , NO2 , and O3 ) at the time of the exercise test were collected from public registers. We compared the pollutant concentrations with the proportion and severity of EIB and adjusted the analyses for air humidity and pollen counts. Pollution levels were rarely high (median PM2.5 6.0 µg/m3 , NO2 12.0 µg/m3 , and O3 47.0 µg/m3 ). The relative change in resistance at 5 Hz after exercise did not correlate with O3 , NO2 or PM2.5 concentrations (p values 0.065-0.884). In multivariate logistic regression, we compared the effects of PM2.5 over 10 µg/m³, absolute humidity (AH) over 10 g/m³ and alder or birch pollen concentration over 10 grains/m³. High (over 10 g/m3 ) AH was associated with decreased incidence (OR 0.31, p value 0.004), and PM2.5 over 10 µg/m³ was associated with increased incidence (OR 1.69, p value 0.036) of EIB. Even low PM2.5 levels may have an effect on EIB in children. Of the other properties of air, only AH was associated with the incidence of EIB.

Association between outdoor air pollution and chronic rhinosinusitis patient reported outcomes

BackgroundThe aetiology of chronic rhinosinusitis (CRS) is multifactorial with a complex interplay between environmental, microbial endogenous and genetic factors. The impact of outdoor air pollution on prevalence or severity of CRS remains largely unknown.MethodsReal-life geolocation data (2017–2018, Belgium) from 278 CRS patients (2576 health records) using the mySinusitisCoach mobile application were analysed to calculate the patients’ individual exposure to outdoor air pollutants (ozone (O3), black carbon (BC), nitrogen dioxide (NO2) and particulate matter with diameter < 2.5 μm (PM2.5)) and to associate these pollutants with the patients’ sinus related symptoms measured at multiple occasions by visual analogue scale (VAS).ResultsThe adjusted seasonal model for the spring–summer (n = 1000 health entries, N = 83 patients) population revealed an increase of 6.07 (p < 0.0001) in overall CRS symptom scoring for an interquartile range (IQR) increase in exposure to O3 (26.9 μg/m3). An increase of 1.69 (p = 0.05) in total CRS symptom scoring was observed for an IQR increase of PM2.5 (7.1 µg/m3) exposure. Sex-stratified analysis in the spring–summer population showed significant interaction between air pollution and sex with male patients having higher total CRS symptom scores for an IQR increase in exposure to PM2.5 (3.52, p = 0.001), and O3 (8.33, p < 0.0001), while no significant association with symptom severity was seen in the female patients. In the analysis stratified by comorbid asthma, CRS patients with comorbid asthma had higher total CRS symptoms for an IQR increase in exposure to PM2.5 (2.58, p = 0.04) and O3 (7.72, p < 0.0001) while the patients without comorbid asthma had no significant symptom increases.ConclusionExposure to outdoor air pollution is associated with increased symptom severity in CRS patients. The extent to which CRS patients are sensitive to outdoor air pollution exposure varies per season and depends on their sex and comorbid asthma status. mHealth technology has the potential to reveal novel insights on the patients’ exposome and disease severity in the real-life situation.

Investigation of vertical distribution of ambient air particulate matter (PM2.5 and PM10) concentration at the respiratory heights of children and adults

&#x0D; &#x0D; &#x0D; &#x0D; Introduction: Air pollution is one of the most important environmental risks to human health. The particulate matter tend to be carcinogenic for humans and can pose a greater hazard to children due to their immaturity and lack of development of the immune system. The current study is aimed to investigate the difference in the concentration of Particulate Matter (PM2.5 and PM10) in the ambient air in the breathing height of children and adults.&#x0D; Materials and methods: Particulate matter were measured cross-sectionally in sidewalks, streets, alleys, squares, and parks of Tehran simultaneously at two heights of 160 cm and 70 cm from the ground. As well as, other variables such as vegetation, buildings and meteorological data were also measured in each location.&#x0D; Results: There was a difference between the concentration of PM2.5 at the breathing height of children, with the average concentration of 52.0 μg/ m3, and the concentration of PM2.5 at the breathing height of adults with the average concentration of 51.6 μg/m3, with p-value of 0.013. Even though the difference is significant, it does not seem to have a significant impact on health. No significant difference was observed between the PM10 concentration at the breathing height of children and adults; however, there was significant difference between the concentrations of PM2.5 with the clean air standard of Iran and data from monitoring stations.&#x0D; Conclusion: The amount of PM2.5 and PM10 is almost the same in children and adults based on the difference in breathing height.&#x0D; &#x0D; &#x0D; &#x0D;

Editorial for the Special Issue “Advances in Air Pollution Meteorology”

This Special Issue of the open-access journal Atmosphere, “Advances in Air Pollution Meteorology”, presents papers that highlight important research showing the relationships between meteorology, emissions and air pollutants, including ozone and particulate matter [...]

Multi-element Quantitative Analysis of Single Micro-sized Suspended Particles in Air with High Accuracy Based on Random Forest and Variable Selection Strategies.

The chemical compositions of atmospheric particles have been studied for several decades, and the traditional techniques for particle analysis usually require time-consuming sample preparation. Within this study, simultaneous quantitative detection of multiple metallic species (Zn, Cu, and Ni) in single micro-sized suspended particles was investigated by combining random forest (RF) and variable selection strategies. Laser-induced breakdown spectra of 15 polluted black carbon samples were applied for establishing the RF model, and the movmean smoothing spectral pretreatment method and variable selection methods [variable importance measurement (VIM), genetic algorithm (GA), and variable importance projection (VIP)] were proposed. Finally, the optimized RF calibration model with the evaluation indicators of mean relative error (MRE), root-mean-square error (RMSE), and coefficient of determination (R2) was constructed based on the optimal input variables and model parameters. Compared with the univariate regression method, the VIP-RF (Zn) and VIM-RF (Cu and Ni) models showed a better correlation relationship (Rp2 = 0.9662 for Zn, Rp2 = 0.9596 for Cu, and Rp2 = 0.9548 for Ni). For Zn, Cu, and Ni, the values of RMSEP (RMSE of prediction) decreased by 116.44, 68.94, and 102.10 ppm, while the values of MREP (MRE of prediction) decreased by 67, 55, and 48%, respectively. The values of ratio of prediction to deviation (RPD) of VIP-RF (Zn), VIM-RF (Cu), and VIM-RF (Ni) models were 5.4, 5.0, and 4.7, respectively. The performance of this combined approach displays a notable accuracy improvement in the quantitative analysis of single particles, suggesting that it is a promising tool for real-time air particulate matter pollution monitoring and control in the future.

Elemental Variability of PM2.5 Aerosols in Historical and Modern Areas of Jeddah, Saudi Arabia

Air particulate matter with a diameter of 2.5 µm (PM2.5) were assembled for a whole year from the historical Jeddah district. Additional PM2.5 aerosols were collected during the autumn and winter seasons from another newly constructed district in Jeddah city (Alnaeem). The annual concentration of the total mass of the PM2.5 aerosols from the historical Jeddah site was found to be 43 ± 6 µg/m3. In addition, the average of the total mass concentration at the Alnaeem site was 61 ± 14 µg/m3. These values were greater than the annual mass concentration of the air quality standards of the European Commission (25 µg/m3) and the World Health Organization (10 µg/m3). The elemental analysis of the collected fine atmospheric aerosols was achieved by energy dispersive X-ray fluorescence (EDXRF) with three secondary targets (CaF2, Ge, and Mo). Quantitative elemental analyses of twenty-two (22) elements were achieved starting from the low atomic number element (Na) up to the high atomic number element (Pb). Although the historical Jeddah site is not well organized, the elemental concentrations and total mass concentrations were lower than those of the other site. The statistical analyses including enrichment factors, correlation analysis, and the principal component analysis revealed more information about the source identification of the PM2.5 aerosols collected from both locations. It was recognized that the elements Al, Si, K, Ca, Ti, Mn, Fe, Rb, and Sr originated from a natural source. On the other hand, the elements Ta, Br, Pb, Sc, Ni, Cu, Zn, and S originated from anthropogenic sources. Finally, the elements Na, Cl, and Br came mainly from the sea spray source.

The relationship between outdoor air pollutants and atopic dermatitis of adults: A systematic review and meta-analysis.

Atopic dermatitis (AD) poses a significant disease burden in adults. Environmental factors are essential in its pathogenesis. Given the possible role of air pollutants in allergic diseases, it is worthwhile to summarize the effects of outdoor air pollution on adult AD. We undertook a systematic review based on PubMed and EMBASE as of August 16, 2021, and found 20 relevant studies. A random-effects meta-analysis was carried out. Regarding long-term effects (within months to years), traffic-related air pollution and particulate matter < 2.5 μm in diameter (PM2.5, per 10 μg/m³ increment) are associated with the prevalence of adult AD (OR 1.40, 95%CI [1.24, 1.58] and 1.67, 95%CI [1.26, 2.21]). Exposures to PM2.5 and nitrogen dioxide are associated with incident AD, with ORs of 2.30 (95%CI: 1.25, 4.25) and 1.30 (95%CI: 1.04, 1.61) per 10 μg/m³ increment. In terms of short term effects (within days), exposure to particulate matter < 10 μm in diameter (PM10) and sulfur dioxide (SO₂) are associated with exacerbations of AD at lag day 0 based on those time-series studies, with an excessive risk of 2.9%, in particular, per 10 μg/m³ increment in SO₂ exposure. In addition, both short-term and long-term exposures to these air pollutants are associated with AD symptoms (eczema, pruritus, and sleep disturbance). Outdoor air pollutants exert both short-term and long-term adverse effects on adult AD, contributing to its development, severity and exacerbation of symptoms. The influence of air pollution should be considered in the management of adult AD.

Understanding the influence of summer biomass burning on air quality in North India: Eight cities field campaign study

Near real-time monitoring of major air pollutants, i.e., particulate matter (PM10, PM2.5, PM1), trace gases (O3, CO, NO, NO2, NOx, NH3, CO2, SO2) and Volatile Organic Compounds (VOCs: benzene, ethylbenzene, m-, p-xylene, o-xylene and toluene) along with climatological parameters was done in eight-cities field campaigns during the rabi (wheat) crop residue burning period in the northwest of Indo-Gangetic Plain (IGP) region. The phase-wise monitoring was done at eight locations representing rural, semi-urban and urban backgrounds. During the whole campaign, the semi-urban site (Sirsa) observed the highest average concentration of PM10 (226 ± 111 μg m−3) and PM2.5 (91 ± 67 μg m−3). The urban site (Chandigarh) reported the minimum concentrations of all the three size fractions of particulate matter with PM10 as 89 ± 54 μg m−3, PM2.5 as 42 ± 22 μg m−3 and PM1 as 20 ± 13 μg m−3 where the monitoring was done in the early phase of the campaign. The highest VOC concentration was recorded at the semi-urban (Sirsa) site, whereas the lowest was at a rural location (Fatehgarh Sahib). NH3 concentration was observed highest in rural sites (31.7 ± 29.8 ppbv), which can be due to the application of fertilizers in agricultural activities. Visible Infrared Imaging Radiometer Suite (VIIRS) based fire and thermal anomalies, along with HYSPLIT back trajectory analysis, show that major air masses over monitoring sites (22 %–70 %) were from the rabi crop residue burning regions. The characteristic ratios and Principal component analysis (PCA) results show that diverse sources, i.e., emissions from crop residue burning, solid biomass fuels, vehicles and industries, majorly degrade the regional air quality. This multi-city study observed that semi-urban regions have the most compromised air quality during the rabi crop residue burning and need attention to address the air quality issues in the IGP region.

Short-term ambient particulate matter pollution of different sizes and respiratory hospital admission in the Beibu Gulf area of Southern China

BackgroundAmbient particulate matter (PM) pollution is associated with occurrence of respiratory diseases; however, limited evidence exists on the effects of PM1 due to lack of ground-based PM1 measurements. ObjectiveTo examine the associations of short-term exposure to PM1, PM2.5 and PM10 with respiratory hospital admission, as well as the attributable burden. MethodsA total of 558,012 respiratory hospital admissions records were collected from 15 cities in the northeast Beibu Gulf of China from 2013 to 2016. Short-term exposures to pollutants (PM1, PM2.5 and PM10) were estimated using a bilinear interpolation approach at residential addresses. A time-stratified case-crossover design was constructed to estimate the associations and the burden of respiratory admissions attributable to ambient air pollution. ResultsWe observed significant associations between PM and respiratory hospitalizations. Odds ratios per 10 μg/m3 increment in two-day averaged concentration were 1.017 (95% CI: 1.012, 1.021) for PM1, 1.010 (95% CI: 1.007, 1.013) for PM2.5, and 1.007 (95% CI: 1.006, 1.009) for PM10. Males in the warm season appeared to be more vulnerable to the impacts of ambient PM pollutants. We further estimated that 3.0% (95% CI: 2.7%, 3.2%), 6.5% (95% CI: 5.9%, 6.8%) and 1.8% (95% CI: 1.6%, 1.9%) of respiratory hospital admissions were attributable to short-term exposure of PM1, PM2.5 and PM10, respectively. ConclusionsShort-term exposure to ambient PM might be an important risk factor for respiratory diseases hospital admissions. If environmental PM air pollutants were reduced to current guideline levels set forth by the government, a substantial proportion of respiratory hospitalizations would be mitigated as a result.

An evaluation of occupant health and indoor environmental quality in university workspaces

Indoor environmental quality is an important parameter in determining the occupant’s health status in the office environment. To show the important connection between human health and environmental quality, this study was carried out to investigate the relationship between Indoor Air Quality (IAQ), the prevalence of health symptoms, selected personal factors, and office characteristics among university office workers. Six parameters of IAQ, including air temperature, relative air humidity, formaldehyde, particulate matter, carbon monoxide, and carbon dioxide, were measured by a direct reading instrument. We found eye irritation, dryness, and itching were the most common health symptoms, and the prevalence of weekly dermal, mucosal, psychological, and general symptoms were 60.9%, 75.4%, 60.8%, and 64.7%, respectively. Age, and working experience were associated with general symptoms, while gender was related to dermal symptoms. Furthermore, we observed that the prevalence of health symptoms in 15–30 years old office rooms was significantly higher than others, and health symptoms among employees with 11–20 years of working experience were higher than other age groups. Strategies like using a proper ventilation system, air cleaners, maintaining social distance, humidity, and temperature control can help to improve indoor air quality and protect us from the risk of airborne transmitted diseases.

Quantifying the potential contribution of urban trees to particulate matters removal: A study in Chattogram city, Bangladesh

Urban trees have capacity to reduce atmospheric particulate matters (PM) concentration through deposition on leaves. However, we have very limited studies on the contribution of urban trees toward removal of PM in Bangladesh. In this study, conducted in Chattogram City Corporation (CCC), Bangladesh, we aimed to i) quantify the ambient atmospheric PM (PM2.5 and PM0.50), ii) quantify deposition of PM by urban trees, and iii) find out variation of PM with respect to common tree species, height of trees (low: 2.0–3.5 m and mid: 3.5–4.5 m), leaf traits (shape, surface), and seasons. Monthly air PM concentrations were measured from September 2020 to April 2021 in six sites (viz. roadside, residential, industrial, commercial, medical, and park area) in CCC. For measuring PM deposition, we collected 128 sample leaves from eight randomly selected trees of eight tree species in every month from study sites. At roadside, where relative greenspace was lowest, the atmospheric PM concentration was the highest. Conversely, where relative greenspace was higher (e. g. residence and park), the PM concentration was the lowest. In winter season (December–February), both ambient PM concentrations and deposition on leaves were the highest. Psidium guajava had significantly (p < 0.05) higher PM deposition than other tree species at both height levels. Deposition of PM was highest in trees with oblong and ovate-shaped, and rough-surfaced leaves at lower height, and therefore, recommendation is made to plant trees with these attributes in urban areas.

Levels of selected heavy metals in blood and urine of workers of Alkali Kongo Plaza GSM Market within Lafia Metropolis, Nasarawa State, Nigeria

The health risk assessment of selected heavy metals in the blood and urine of workers, as well as the sound and air qualities of Alkali Kongo Plaza GSM Village in Lafia Metropolis, Nasarawa State, was conducted. While the heavy metals were determined using atomic absorption spectrophotometry, the sound and air qualities were determined using a hand-held integrated sound level meter and multifunctional air detector (model; WP6910). The blood and urine samples were obtained from the handset repairers and sellers in the market and investigated for their heavy metals such as Pb, Cd, Mn, Ni, and Cr contents. The air quality status was investigated for particulate matter (PM), total volatile organic compounds (TVOCs), and formaldehyde (HCHO). Before analyzing the heavy metals, the collected samples were treated and then digested using standard procedures. The urine samples showed higher concentrations of Mn, Pb, and Ni, while in the blood samples, there were high concentrations of Mn, Pb, Ni, and Cr. The concentration of Mn in the blood samples ranged from 14.22 to 22.63 µg/dm3 and from 8.30 to 12.20 µg/dm3 in the urine. The concentration of Pb in blood varied between 190.10 and 212.10 µg/dm3, while that of urine varied from 141.90 to 215.00 µg/dm3. The concentration of Cd in blood varied between 1.86 and 1.95 µg/dm3 and from 5.10 to 13.70 µg/dm3 in the urine. The concentration of Cr in blood ranged from 12.75 to 16.44 µg/dm3, while that of urine ranged from 23.00 to 15.20 µg/dm3. On the other hand, Ni concentration in blood ranged from 18.70 to 24.90 µg/dm3, while that of urine ranged from 17.90 to 31.00 µg/dm3. The air quality parameters, PM, TVOCs, HCHO, and noise or sound pollutants indicated higher values than the control and the standard values. From these results, 83% of the workers of the community market stand a high chance of being at risk, especially due to the high concentrations of Mn and Pb. Hence, there are need to monitor the occupational activities of denizens of this commercial center for the proper establishment of levels of the selected parameters in this study and parameters that were not considered.

Cardiovascular disease, mortality and exposure to particulate matter (PM): a systematic review and meta-analysis.

One of the main factors that causes health effects in humans such as hospital admissions for cardiovascular disease (HACVD), respiratory disease (RD), lung function, cardiovascular mortality (MCVD), lung cancer, and increased mortality is air pollution especially particulate matter (PM). This a systematic review and meta-analysis aims to investigate the effects of particulate matter on the occurrence of cardiovascular disease and mortality. A systematic review and meta-analysis of the literature was done from 2011 to 2021 based on various databases. Based on the result of this study, subgroup analysis based on temperature conditions showed a different estimation in cold cities (6.24, UR (4.36-8.12)), moderate cities (4.86, UR (3.57-6.15)) and warm cities (8.96, UR (7.06-10.86)). Test of group differences showed asignificant difference (Q=12.22, p-value<0.001). There was publication bias among the studies (the Egger's test; (Z=14.18, p<0.001)). According result study pooled estimation of AP% for MCVD from the random-effect meta-analysis based on DerSimonian-Laird model, overall is 5.04, UR (3.65-6.43) (Figure4). Subgroup analysis based on temperature conditions showed the estimation in cold cities (5.47, UR (3.97-6.97)) and moderate cities (4.65, UR (0.54-8.77)). Test of group differences showed a non-significant difference (Q=0.13, p-value=0.71). There was no publication bias among the studies (the Egger's test; (Z=0.82, p=0.376)). Exposed to air pollutants and particulate matter can be increase the risk of cardiovascular disease, respiratory disease, and cardiovascular mortality.

Compromised Improvement of Poor Visibility Due to PM Chemical Composition Changes in South Korea

Fine particulate matter (PM) significantly affects visibility, a sensitive indicator of air pollution. Despite a continuous decrease in the PM concentrations in South Korea, the public generally believes that PM air pollution has worsened over the past years. To explain this disparity, we analyzed the characteristics of recent visibility changes using observations of visibility and PM component data observed in Seoul, South Korea, from 2012 to 2018. A significant negative correlation (R = −0.96) existed between visibility and concentrations of PM, with an aerodynamic diameter ≤ 2.5 μm (PM2.5); a high PM2.5 concentration was the most important contributor to poor visibility. Annual mean PM2.5 concentrations in Seoul decreased by −5.1% yr−1 during 2012–2018, whereas annual mean visibility improved by 2.1% yr−1. We found that a lower improvement in visibility was associated with changes in the PM component. Among the PM components affecting poor visibility, contributions of ammonium nitrate (NH4NO3) significantly increased during 2012–2018 (from 48% in 2012 to 59% in 2018). Increases in NO3− aerosol concentrations were owing to SOx emission reduction and the resulting decreases in SO42− aerosol concentrations, which led to an increase in NH3 available for additional NH4NO3 production in the atmosphere. Despite decreased PM concentrations in Seoul, the change of PM components has compromised visibility improvement; thus, NO3− concentrations need to be reduced.

Co-Exposure of Ambient Particulate Matter and Airborne Transmission Pathogens: The Impairment of the Upper Respiratory Systems.

Recent evidence has pinpointed the positive relevance between air particulate matter (PM) pollution and epidemic spread. However, there are still significant knowledge gaps in understanding the transmission and infection of pathogens loaded on PMs, for example, the interactions between pathogens and pre-existing atmospheric PM and the health effects of co-exposure on the inhalation systems. Here, we unraveled the interactions between fine particulate matter (FPM) and Pseudomonas aeruginosa (P. aeruginosa) and evaluated the infection and detrimental effects of co-exposure on the upper respiratory systems in both in vitro and in vivo models. We uncovered the higher accessibility and invasive ability of pathogens to epithelial cells after loading on FPMs, compared with the single exposure. Furthermore, we designed a novel laboratory exposure model to simulate a real co-exposure scenario. Intriguingly, the co-exposure induced more serious functional damage and longer inflammatory reactions to the upper respiratory tract, including the nasal cavity and trachea. Collectively, our results provide a new point of view on the transmission and infection of pathogens loaded on FPMs and uncover the in vivo systematic impairments of the inhalation tract under co-exposure through a novel laboratory exposure model. Hence, this study sheds light on further investigations of the detrimental effects of air pollution and epidemic spread.

The need for multifaceted approaches when dealing with the differing impacts of natural disasters and anthropocentric events on air quality

Air pollution associated health issues are increasing globally. This is due to both anthropogenic sources, such as traffic, and natural sources, such as bushfires. Natural disasters, such as bushfires, impact air quality by releasing large concentrations of pollutants affecting respiratory health. However, another recent global event has also had severe impacts on the environment and health, the global COVID-19 pandemic. Global pandemics, such as COVID-19, can also influence air quality by altering human activity, resulting in its own associated health impacts. This study aimed to investigate the impact of a natural disaster and global pandemic on outdoor ambient air pollution by quantifying and comparing the spatial distribution of two air pollutants, nitrogen dioxide (NO2) and particulate matter (PM10), during the different periods across the Greater Sydney region, Australia, while correcting for anthropogenic sources and meteorological influences such as temperature and rain. COVID-19 and bushfire affected periods were compared to a control period when both of these influences were absent. We found that NO2 was significantly higher during the COVID-19 pandemic than during the control period and the recent 2019 bushfires. Conversely, PM10 was significantly lower during the COVID-19 pandemic than the bushfire and control periods. The spatial distribution of both pollutants and influencers also varied across the study site. These results suggest that both events markedly impacted air quality, although they impacted the air pollutants differently. These findings further demonstrate a greater need to understand the impact of natural disasters and anthropocentric events on air pollution as multifaceted, spatially relevant policies are required to address these events, particularly if they increase in frequency or severity in the future.

Health and economic impacts of ambient air particulate matter (PM2.5) in Karaj city from 2012 to 2019 using BenMAP-CE.

The present study aims to estimate the effects of PM2.5 on the health and economy of Karaj city from 2012 to 2019. In this study, mortality attributed to long-term exposure to PM2.5 and its spatial distribution in Karaj over the 2012-2019 period were estimated using the Global Exposure Mortality Model (GEMM) concentration-response function and BenMAP software. PM2.5 hourly concentration data of air quality monitoring stations were used to estimate PM2.5 for the whole city of Karaj. The economic effects of this pollutant were also assessed using the value of statistical life (VSL) method. The results showed that the annual average PM2.5 concentration during the studied time increased and was higher than the air quality guideline levels recommended by the World Health Organization. Also, the annual number of deaths attributed to PM2.5 in adults (older than 25years) was estimated to be about 1200. The highest to lowest proportions of PM2.5-related deaths were non-accidental mortality, ischemic heart attack, stroke, acute respiratory tract infection, chronic obstructive pulmonary disease (COPD), and lung cancer, in the order of their appearance. The results showed that the economic loss attributed to this pollutant was estimated at 380 to 504 million USD per year. Due to the effects of PM2.5 on health and the economy in this city, we suggest conducting special planning to control and reduce the concentration of ambient air particulate matter by improving the public transportation system and updating industrial processes.

Changes in particulate matter concentration and meteorological variables after changing forest structure in oak-dominated forests nearby highway tollgate

Oak species are the major dominant tree species of deciduous forests, but the little study was conducted to understand the change of particulate matter concentration after changing the forest structure. This study analyzed the effects of changing forest structure (CFS) on the changes in meteorological factors and air particulate matter (PM) concentration after leaf emergence in oak-dominated forests nearby highway pollutants’ sources. In June 2019, 33% of the total trees were removed from the CFS of oak forests in the vicinity of the tollgate of Misiryeong in Goseong-gun, Gangwon-do, Korea. To understand the changes in leaf emergence between the treatment site (TRS is the site changing forest structure) and control site (CS), we investigated the foliage height profile (FHP, %) at each class of tree height in December 2019 and June 2020. The results showed that FHP (%) was lower in TRS than in CS in both months, and the FHP of the middle canopy class increased after TRS while that of the upper canopy class decreased. The correlation was significant with temperature in March (p < 0.01) and with wind speed in June (p < 0.01), indicating that CFS improved the airflow. There was no significant difference in the PM concentration between CS (PM10: 37.7 µg/m3, PM2.5: 21.1 µg/m3) and TRS (PM10: 37.5 µg/m3, PM2.5: 20.8 µg/m3) in March; however, the PM concentration in TRS (PM10: 65.0 µg/m3, PM2.5: 26.2 µg/m3) was lower than that in CS (PM10: 73.9 µg/m3, PM2.5: 29.1 µg/m3) in June. The rate of PM reduction (%) in TRS was higher in June (PM10: 11.3%, PM2.5: 10.0%) than in March (PM10: 2.3%, PM2.5: 4.0%). The low value of PM concentration in June could be related to the leaf emergence. Overall, the results indicated that meteorological factors and PM concentrations had changed in the inner part of the forest after leaf emergence and that the temperature and wind speed were strongly correlated with the PM concentration. These results suggest that CFS can change the forest structure and the airflow in oak-dominated forests, which PM can flow and settle down into the inner forest's nearby pollutants sources of a tollgate. The results provide basic information for understanding the reduction effect of PM by CFS in oak-dominated deciduous forests nearby highway pollutants source.