Atmospheric PM2 Research Articles

Characterization of particulate organic nitrates in the Yangtze River Delta, East China, using the time-of-flight aerosol chemical speciation monitor

Particulate organic nitrates (pON) are important species in the atmosphere that influence reactive nitrogen cycling and ozone (O3) formation. Previous studies on pON focused on forest regions involving anthropogenic NOx emissions. Therefore, the investigation and quantitation of pON in polluted urban regions remain limited. Here, we conducted sampling campaigns in four seasons using an Aerodyne time-of-flight aerosol chemical speciation monitor in the SORPES station in Nanjing, East China. pON were calculated using a constrained-PMF method, which was validated using high-resolution aerosol mass spectrometer-based estimates. The results reveal that pON contribute significantly to the aerosol nitrate in the polluted Yangtze River Delta, and the fractions of pON to total nitrate are >21% in the summer, spring, and autumn, and >13% in the winter. The pON contribution to the total nitrate decreases as the fine particulate matter (PM2.5) loading increases but remaines significant at the peak of pollution. This indicates that the pON formation is controlled by the gas-phase chemistry, which is pronounced during low PM2.5 pollution. pON are also associated with organic matter (OM), and its contribution to the OM is independent of the PM2.5 loading. The contributions to OM are 36.2%, 25.6%, 24.1%, and 13.9% during the winter, autumn, spring, and summer, respectively. Our study demonstrates that pON are potentially important components of atmospheric PM2.5 in urban areas.

Dining Lampblack Treatment Processes in China

The PM2.5 and other small particles produced by cooking oil fumes have contributed up to 25% to the urban atmospheric PM2.5, which has a bad impact on air quality and seriously threatens human health. Aiming at the pollution problem caused by catering oil fume, this article analyzes the threats of air pollution to human health based on the compositions and characteristics of catering oil fume, illustrates the development trend of China′s food and beverage lampblack control policy, and summarizes and points out the current situation and development trend of catering oil fume treatment. In order to provide ideas for the design of more efficient and energy-saving treatment processes in the future, the advantages and disadvantages were reviewed, and the improvement direction of the treatment technology was discussed.

Dynamic variations of phthalate esters in PM2.5 during a pollution episode

Phthalate esters (PAEs) as hazardous air pollutants can be easily released during the life cycle of plastic products. In this study, a thermal desorption aerosol comprehensive two-dimensional gas chromatography mass spectrometer coupled with a dual-trap was developed and used to measure the hourly-resolved PAEs characteristics in atmospheric PM2.5 at an urban site. Dimethyl phthalate (DMP), diethyl (DEP), dibutyl (DnBP), benzyl butyl (BBP), di(2-ethylhexyl) (DEHP), and di-n-octyl phthalate (DnOP) in PM2.5 were analyzed. The most abundant compounds were DEHP and DMP, followed by DnBP and DEP. The mass concentrations of the detected PAEs are comparable to those at other urban sites measured using offline methods with a lower time resolution. The concentrations of PAEs showed intense change with the variation of PM2.5 mass concentration. The proportion of DEHP increased while that of DMP decreased with the increase in PM2.5 pollution. Positive correlations between PAEs and PM2.5, organic carbon, and elemental carbon were observed, while PAEs had negative correlation with the ambient temperature. Our observation provides evidences on understanding the volatile and semi-volatile PAEs in the ambient aerosols.

Role of notch signaling pathway in Muc5ac secretion induced by atmospheric PM2.5 in rats

BackgroundThe secretion of Muc5ac is closely related to the pathogenesis, treatment and prognosis of bronchial asthma. Atmospheric PM2.5 entered the airway can irritate and corrode the bronchial wall, affecting the expression and secretion of Muc5ac. However, the underlying mechanism is not clear. In this study, we investigated the role of the Notch signaling pathway in mucin section induced by atmospheric PM2.5 in rats. MethodsFifty rats were divided randomly into five groups: the control received physiological saline; the health, health Notch signaling pathway inhibition and asthma, asthma Notch signaling pathway inhibition groups received 7.5 mg/kg PM2.5. PM2.5 or saline was instilled into the trachea at 2-day intervals for two doses. IL-1β, TNF-α and Muc5ac levels were detected by ELISA. The mRNA expression levels of Notch signaling pathway genes were detected by real time PCR. The levels of Notch signaling pathway protein were detected by western blot. ResultsThe levels of Muc5ac in the lungs and TNF-α in serum of asthmatic rats exposed to PM2.5 was the highest, and when Notch signaling pathway was inhibited, the levels of Muc5ac in the lungs and tracheas and TNF-α in serum of asthmatic rats exposed to PM2.5 was significantly decreased. Hes1 mRNA expression level in trachea was the lowest in the asthma inhibition group; and inhibiting the Notch signaling pathway could decrease the mRNA and protein levels of Hes1 in rats’ lung. The mRNA relative levels of Notch3 and Notch4 in rats’ trachea, the protein levels of Notch3 in rats’ lung, and the mRNA relative levels of Jagged1 and Jaggeed2 in rats’ lung were more consist with the changes of Muc5ac, TNF-α and Hes1. ConclusionNotch signaling pathway played an important role in Muc5ac secretion induced by atmospheric PM2.5 of the asthmatic rats’ airways. Jagged1 and Jagged2 interacting with Notch3 and Notch4 regulated the expression of Hes1, further regulated TNF-α in the process of PM2.5 inducing the secretion of Muc5ac.

Mechanism of Pb accumulation in Chinese cabbage leaves: Stomata and trichomes regulate foliar uptake of Pb in atmospheric PM2.5

Chinese cabbage (Brassica rapa ssp. pekinensis) is one of the most popular and frequently consumed leafy vegetables. It was found that atmospheric PM2.5-Pb contributes to Pb accumulation in the edible leaves of Chinese cabbage via stomata in North China during haze seasons with high concentrations of fine particulate matter in autumn and winter. However, it is unclear whether both stomata and trichomes co-regulate foliar transfer of PM2.5-Pb from atmospheric deposition to the leaf of Chinese cabbage genotypes with trichomes. Field and hydroponic experiments were conducted to investigate the effects of foliar uptake of PM2.5-Pb on Pb accumulation in leaves using two genotypes of Chinese cabbage, one without trichomes and one with trichomes. It was verified that open stoma is a prominent pathway of foliar PM2.5-Pb transfer in the short-term exposure for 6 h, contributing 74.5% of Pb accumulation in leaves, whereas Pb concentrations in the leaves of with-trichome genotype in the rosette stage were 6.52- and 1.04-fold higher than that of without-trichome genotype in greenhouse and open field, respectively, which suggests that stomata and trichomes co-regulate foliar Pb uptake of from atmospheric PM2.5. Moreover, subcellular Pb in the leaves was distributed in the following order of cytoplasm (53.8%) > cell wall (38.5%)> organelle (7.8%), as confirmed through high-resolution secondary ion mass spectrometry (NanoSIMS). The Leadmium™ Green AM dye manifested that Pb in PM2.5 entered cellular space of trichomes and accumulated in the basal compartment, enhancing foliar Pb uptake in the edible leaves of cabbage. The results of these experiments are evidence that both stomata and trichomes are important pathways in the regulation of foliar Pb uptake and translocation in Chinese cabbage.

Regional Air Pollutant Characteristics and Health Risk Assessment of Large Cities in Northeast China

This study systematically investigated the pollution characteristics of atmospheric O3 and PM2.5, regional transport, and their health risks in three provincial capitals in northeast China during 2016–2020. The results show that O3 concentrations showed a trend of high summer and low winter, while PM2.5 concentrations showed a trend of high winter and low summer during these five years. The results of the correlation analysis indicate that external sources contribute more O3, while PM2.5 is more from local sources. The backward trajectory clustering analysis results showed that Changchun had the highest share of northwest trajectory with a five-year average value of 67.89%, and the city with the highest percentage of southwest trajectory was Shenyang with a five-year average value of 23.95%. The backward trajectory clustering analysis results showed that the share of the northwest trajectory decreased and the share of the southwest trajectory increased for all three cities in 2020 compared to 2016. The results of the potential source contribution function (PSCF) and concentration weighting trajectory (CWT) analysis showed that the main potential source areas and high concentration contribution areas for PM2.5 in the northeast were concentrated in Mongolia, Inner Mongolia, Shandong Province, and the northeast, and for O3 were mainly located in Shandong, Anhui, and Jiangsu Provinces, and the Yellow Sea and Bohai Sea. The non-carcinogenic risk of PM2.5 in Harbin was high with a HQ of 2.04, while the other cities were at acceptable levels (HQ < 0.69) and the non-carcinogenic risk of O3 was acceptable in all three cities (HQ < 0.22). However, PM2.5 had a high carcinogenic risk (4 × 10−4 < CR < 0.44) and further treatment is needed to reduce the risk.

Spatial Variation of the Effect of Multidimensional Urbanization on PM2.5 Concentration in the Beijing-Tianjin-Hebei (BTH) Urban Agglomeration.

Atmospheric PM2.5 pollution has become a prominent environmental problem in China, posing considerable threat to sustainable development. The primary driver of PM2.5 pollution in China is urbanization, and its relationship with PM2.5 concentration has attracted considerable recent academic interest. However, the spatial heterogeneity of the effect of urbanization on PM2.5 concentration has not been fully explored. This study sought to fill this knowledge gap by focusing on the Beijing–Tianjin–Hebei (BTH) urban agglomeration. Urbanization was decomposed into economic urbanization, population urbanization, and land urbanization, and four corresponding indicators were selected. A geographically weighted regression model revealed that the impact of multidimensional urbanization on PM2.5 concentration varies significantly. Economically, urbanization is correlated positively and negatively with PM2.5 concentration in northern and southern areas, respectively. Population size showed a positive correlation with PM2.5 concentration in northwestern and northeastern areas. A negative correlation was found between urban land size and PM2.5 concentration from central to southern regions. Urban compactness is the dominant influencing factor that is correlated positively with PM2.5 concentration in a major part of the BTH urban agglomeration. On the basis of these findings, BTH counties were categorized with regard to local policy recommendations intended to reduce PM2.5 concentrations.

High-resolution inventory of emissions of atmospheric PM10 from agricultural tillage and harvesting operations in China: historical trend, spatio-temporality, and optimization methodology

High-resolution inventory of emissions of atmospheric PM10 from agricultural tillage and harvesting operations in China: historical trend, spatio-temporality, and optimization methodology

The evolution trend and typical process characteristics of atmospheric PM<sub>2.5</sub> and O<sub>3</sub> pollution in Beijing from 2013 to 2020

The evolution trend and typical process characteristics of atmospheric PM<sub>2.5</sub> and O<sub>3</sub> pollution in Beijing from 2013 to 2020

Molecular characterization of organic aerosol in winter from Beijing using UHPLC-Orbitrap MS

The urban organic aerosol (OA) may pose a serious threat to human health and ecological environment. In order to understand the molecular characteristics of organic compounds in aerosols, atmospheric PM2.5 samples were collected in Beijing and the extracts were analyzed by liquid chromatography-Orbitrap mass spectrometry combined with negative-ion electrospray ionization, positive-ion electrospray ionization, and positive-ion atmospheric pressure photoionization sources. The combination of multiple ionization sources realized the comprehensive molecular characterization of organic compounds in OA, and 1976 (+APPI), 3038 (−ESI), and 4376 (+ESI) molecular formulas were identified in this study. Significant differences in the species, abundance, and number of subgroups (CHO, CHN, CHON, CHONS, CHOS, and CH compounds) were clarified. Chemical fingerprinting of organics in the PM2.5 extract were investigated by high-throughput non-target compound analytical methods. Structure induction of organic compounds was realized through fragmentation prediction of MS/MS spectra with Sirius software. Furthermore, a total of 50 nitroaromatic formulas, 285 organosulfates (OS) formulas, 57 nitrooxy-OS formulas, 228 CHO- formulas with carboxyl groups, and 36 monoketone formulas were determined based on diagnostic fragmentation filtering. Our results provide important insights into the molecular composition and structural characteristics of OA, and establish foundation for exploring the interaction between composition and physicochemical properties.

Seasonal Variation and Source Apportionment of Carbonaceous Species in PM2.5 in Chengde

In order to study the seasonal variations and pollution sources of carbonaceous species in PM2.5 in Chengde, the concentration of these components was determined in atmospheric PM2.5 samples collected in January, April, July, and October 2019. The change in carbonaceous species were analyzed based on the estimation of the ratio of organic carbon(OC) to elemental carbon(EC), total carbonaceous aerosol(TCA), and secondary organic carbon(SOC). The source of these pollutants was determined by means of the backward trajectory and principal component analysis(PCA). The results showed that the mean mass concentrations of PM2.5, OC, and EC during the sampling period were(31.26±21.39) μg·m-3,(13.27±8.68) μg·m-3, and(2.80±1.95) μg·m-3, respectively. The seasonal variations of PM2.5 were:winter[(47.68±30.37) μg·m-3]>autumn[(28.72±17.12) μg·m-3]>spring[(26.59±15.32) μg·m-3]>summer[(23.17±8.38) μg·m-3], consistent with the trend of total carbon(TC), OC, and EC. The source of OC and EC during winter(R2=0.85) was similar. Based on the ratio of OC/EC, all four seasons were affected by traffic and coal-burning source emissions, and the most affected season by bituminous coal emissions was winter. The average concentration of TCA was(21.38±13.68) μg·m-3, which accounted for 68.39% of PM2.5. The order of secondary conversion rate(SOC/OC) was:spring(54.09%) >autumn(37.64%) >summer(32.91%) >winter(25.43%). The results of the backward trajectory simulation show that the pollutant concentrations carried by air masses are relatively low in spring and summer, and the transport channels of pollutants are southwest in autumn and northwest in winter. The results of the PCA showed that the key to reducing PM2.5 in Chengde is to control emissions from vehicle exhausts, and coal and biomass combustion sources.

Variation in the concentrations of atmospheric PM2.5 and its main chemical components in an eastern China city (Hangzhou) since the release of the Air Pollution Prevention and Control Action Plan in 2013

Variation in the concentrations of atmospheric PM2.5 and its main chemical components in an eastern China city (Hangzhou) since the release of the Air Pollution Prevention and Control Action Plan in 2013

Urban fine particulate air pollution exposure promotes atherosclerosis in apolipoprotein E-deficient mice by activating perivascular adipose tissue inflammation via the Wnt5a/Ror2 signaling pathway

Urban fine particulate matter (PM2.5) is a deleterious risk factor in the ambient air and is recognized to exacerbate atherosclerosis. Perivascular adipose tissue (PVAT) secretes a large number of inflammatory cytokines and plays a crucial role in the pathogenic microenvironment of atherogenesis. However, there is a lack of knowledge about the role of PVAT inflammation in the genesis of PM2.5-related atherosclerosis. The aim of this research was to probe the latent links between PM2.5 exposure and PVAT inflammation and further discovered the underlying mechanisms of PM2.5-triggered atherosclerosis pathogenesis. Apolipoprotein E-deficient (ApoE−/−) mice were exposed to real-world atmospheric PM2.5 or filtered clean air for three months, the Wnt5a inhibitor Box5 and the Ror2 inhibitor β-Arrestin2 were applied to verify the possible mechanisms. We noticed that the average daily PM2.5 mass concentration was 84.27 ± 28.84 μg/m3. PM2.5 inhalation might significantly expedite the deterioration of atherosclerosis, increase the protein and mRNA expressions of MCP-1, IL-6, TNF-α, Wnt5a, and Ror2 in PVAT tissues, upregulate the distributions of IL-6, TNF-α, MCP-1, and leptin in the histological sections of PVAT, promote lipid deposition in the aorta, elevate the plasma levels of leptin, MCP-1, IL-6, TNF-α, LDL-C, TC, and TG, however, decrease the plasma levels of adiponectin and HDL-C, downregulate the distribution of adiponectin. Nevertheless, these effects caused by PM2.5 exposure were dramatically diminished after the administration of Box5 or β-Arrestin2. This research illuminated that PVAT inflammation was involved in the PM2.5-induced atherosclerosis process, as well as lipid deposition, which was closely associated with the activation of the Wnt5a/Ror2 signaling pathway.

PM2.5 promoted lipid accumulation in macrophage via inhibiting JAK2/STAT3 signaling pathways and aggravating the inflammatory reaction

BackgroundAbnormal lipid accumulation in macrophages may lead to macrophages foaming, which is the most important pathological process of atherosclerosis. Atmospheric PM2.5 could enter the blood circulation and further affect the lipid metabolism of macrophages. But the underlying mechanism is not unclear. This study was undertaken to clarify the effect of PM2.5 on lipid metabolism in macrophages, and to explore the role of inflammatory reaction and JAK2/STAT3 signaling pathway in this process. MethodMacrophages derived from THP-1 cells were exposed to PM2.5 (0,100,200,400 μg/mL) for 6 h and 12 h. STAT3 agonist ColivelinTFA is used to specifically excite STAT3. The survival rate of macrophages was detected by CCK-8. The lipid levels in macrophages were detected by colorimetry. The levels of inflammatory factors secreted by macrophages were detected by ELISA. Q-PCR was used to detect the mRNA expression levels, and Western Blot was used to detect the protein expression levels of JAK2/STAT3 pathway genes. ResultThe survival rate of macrophages was reduced by PM2.5, and the levels of TG, T-CHO and LDL-C of macrophages exposed to PM2.5 were increased. PM2.5 led to the increasing level of IL-6 and the decreasing level of IL-4, and the JAK2/STAT3 signaling pathway was inhibited by PM2.5. Colivelin TFA significantly decreased the increasing levels of TG, T-CHO and LDL-C levels, and increased the decreasing mRNA levels of IL-4, and LPL induced by PM2.5 (p < 0.05). DiscussionPM2.5 could cause the lipid accumulation of macrophages by inhibiting the JAK2/STAT3 signaling pathway, and inflammatory responses may be involved in this process.

Responses of surface O3 and PM2.5 trends to changes of anthropogenic emissions in summer over Beijing during 2014–2019: A study based on multiple linear regression and WRF-Chem

Owing to the implementation of air pollution control actions, anthropogenic emissions in Beijing have changed in recent years. Understanding the impact of changes in anthropogenic emissions on O3 and PM2.5 trends is helpful for developing air quality management strategies. Herein, we investigated the variations of air pollutants in summer over Beijing using long-term data sets from 2014 to 2019, and explored the responses of O3 and PM2.5 trends to changes in anthropogenic emissions based on multiple linear regression (MLR) analysis and WRF-Chem model. The results indicated a significant decrease in PM2.5, but a near constant level of O3 during 2014–2019. The decrease rate of PM2.5, which was lower than that of SO2, might be due to the effect of NO2 on atmospheric PM2.5. Both the slightly increasing correlations between PM2.5 and NO2 and the WRF-Chem model simulations implied that atmospheric PM2.5 in Beijing is trending to be more sensitive to NOx than SO2. The emissions of NOx and VOCs from industry and transportation were found to make great contribution to O3 production in Beijing. Due to the titration of NOx in VOC-limited regime, the relatively low emission ratios of NOx and VOCs from industry and transportation in Beijing provided convincing evidence for the persistently high O3 concentrations during 2014–2019. However, the noticeable increase of the O3 trends in other areas (e.g., Hebei, Tianjin) could be explained by the significant decline in the emission ratios of NOx and VOCs from anthropogenic emissions especially industry during 2014–2019. Controlling the emission of NOx can substantially reduce PM2.5 pollution, but may aggravate O3 pollution, and thus effective VOC emission control strategies need to be considered for simultaneously controlling O3 and PM2.5 pollution in Beijing and other regions of China.

CHARACTERIZATION OF AIRBORNE PARTICULATE MATTER TO ASSESS THE IMPACT ON DEGRADATION OF CULTURAL HERITAGE: THE TROPAEUM TRAIANI MONUMENT

The present paper is focused on the microclimatic investigation and weather-climatic phenomena matrix assessment, which can be generated for heritage objectives at different spatial and temporal resolutions, correlated with physicochemical analysis of the particulate matter (PM2.5-10). In the literature the importance of atmospheric PM monitoring in the proximity of monuments is not yet sufficiently highlighted. In this respect, the microclimatic investigation of the Tropaeum Traiani Monument (Adamclisi, Romania) was performed to assess the suitability of a closed environment, located outdoors, according to the conservation requirements of heritage materials. The monitoring campaigns (four seasons, e.g., from summer of the year 2018 to spring of the year 2019) were carried out by non-invasive measuring equipment. The collected data were used to investigate the hygrothermal and chemical behavior inside and outside of Tropaeum Traiani Monument, built in 109, to assess the risks on the oldest structural material. Principal component analysis (PCA) was performed by IBM SPSS Statistics software to assess the similarities between the microclimatic parameters.

Seasonal variations and source apportionment of carbonaceous aerosol in PM2.5 from a coal mining city in the North China Plain

Handan is one of the most polluted coal mining cities in the North China Plain (NCP). There is a lack of research on the pollution characteristics and sources of carbonaceous components in PM2.5 in Handan city. Atmospheric PM2.5 samples were collected from Handan City during 2018 and the organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed with a carbon analyzer. The annual average mass concentrations of PM2.5 and total carbon (TC = OC + EC) in Handan were (101.88 ± 79.01) μg/m3 and (28.03 ± 23.28) μg/m3, respectively. The annual average ratio of TC/PM2.5 was (28.29% ± 7.95%), indicating that carbonaceous components made a major contribution to PM2.5. The seasonal variations of OC and EC concentrations in PM2.5 were consistent with PM2.5, which was higher in winter and lower in summer. The annual average OC/EC ratio was (10.33 ± 5.83), and the (OC/EC)min ratio for each season was greater than 2, suggesting that there was probably secondary organic carbon (SOC) formation all around the year. The correlations between OC and EC during spring and winter were much more significant than during summer and autumn, which indicated that the sources of OC and EC in summer and autumn were more complex. Principal component analysis (PCA) displayed that the main sources of carbonaceous components in PM2.5 were coal combustion emission, road dust and vehicle exhaust, which may be related to coal-fired power generation and steelmaking, and coal transportation in Handan city. The potential source contribution function (PSCF) analysis demonstrated that PM2.5 and carbonaceous components in Handan city were significantly influenced by both local emissions and regional transport during the observation period.

Health impact assessment from exposure to trace metals present in atmospheric PM10 at Ahmedabad, a big city in western India.

Many toxicological studies revealed the deleterious effects on human health induced by trace metals in ambient particulate matter (PM). This study reports the season-dependent water-soluble and total metal mass in PM10 collected simultaneously over five microenvironments in a semi-arid urban region, Ahmedabad, located in western India. The mineral dust fraction in PM10 over Bapunagar, Narol, Paldi, Income Tax, and Science City was estimated to be around 39, 45, 47, 44, and 31% during summer (May-June 2017) and 24, 55, 28, 27, and 28% during winter (December 2017-January 2018), respectively, corroborating mineral dust is perennial in the air over Ahmedabad. The PM2.5/PM10 mass ratios over all the sites were higher during winter (40-60%) as compared to those during summer (30-40%), indicating the contribution from the anthropogenic sources to PM mass. Among the metals monitored, the estimated considerable amount of high masses of Zn, Cu, Ni, Cd, and Sb during winter can be ascribed to the anthropogenic inputs based on the estimated enrichment factors (EF). In contrast to the crustal source, these metals might have been possibly emitted from several other man-made sources, which were found to be more water-soluble during both seasons. As per the standards of incremental excess lifetime cancer risk (IELCR), it is estimated that the atmospheric mass concentration of carcinogenic metals such as Cr, Co, and As was higher in all these sites, whereas the metals such as Pb, Ni, and Cd are also found over the industrial site (Narol) in addition to the above-said metals. Notably, people are highly susceptible to these metals, leading to the potential risk of cancer during both seasons.

Short-term associations of air pollution and meteorological variables on the incidence and severity of COVID-19 in Madrid (Spain): a time series study

BackgroundThere are studies that analyze the role of meteorological variables on the incidence and severity of COVID-19, and others that explore the role played by air pollutants, but currently there are very few studies that analyze the impact of both effects together. This is the aim of the current study. We analyzed data corresponding to the period from February 1 to May 31, 2020 for the City of Madrid. As meteorological variables, maximum daily temperature (Tmax) in ºC and mean daily absolute humidity (AH) in g/m3 were used corresponding to the mean values recorded by all Spanish Meteorological Agency (AEMET) observatories in the Madrid region. Atmospheric pollutant data for PM10 and NO2 in µg/m3 for the Madrid region were provided by the Spanish Environmental Ministry (MITECO). Daily incidence, daily hospital admissions per 100.000 inhabitants, daily ICU admissions and daily death rates per million inhabitants were used as dependent variables. These data were provided by the ISCIII Spanish National Epidemiology Center. Generalized linear models with Poisson link were performed between the dependent and independent variables, controlling for seasonality, trend and the autoregressive nature of the series.ResultsThe results of the single-variable models showed a negative association between Tmax and all of the dependent variables considered, except in the case of deaths, in which lower temperatures were associated with higher rates. AH also showed the same behavior with the COVID-19 variables analyzed and with the lags, similar to those obtained with Tmax. In terms of atmospheric pollutants PM10 and NO2, both showed a positive association with the dependent variables. Only PM10 was associated with the death rate. Associations were established between lags 12 and 21 for PM10 and between 0 and 28 for NO2, indicating a short-term association of NO2 with the disease. In the two-variable models, the role of NO2 was predominant compared to PM10.ConclusionsThe results of this study indicate that the environmental variables analyzed are related to the incidence and severity of COVID-19 in the Community of Madrid. In general, low temperatures and low humidity in the atmosphere affect the spread of the virus. Air pollution, especially NO2, is associated with a higher incidence and severity of the disease. The impact that these environmental factors are small (in terms of relative risk) and by themselves cannot explain the behavior of the incidence and severity of COVID-19.

Organophosphate Esters in Indoor Environment and Metabolites in Human Urine Collected from a Shanghai University.

In China, organophosphate esters (OPEs) are widely used in indoor environments. However, there is little information regarding the internal and external exposure of university students to OPEs. Therefore, in this study, nine OPEs and eight OPE metabolites (mOPEs) were measured in indoor dust and atmospheric PM2.5 samples from a university campus in Shanghai, as well as in urine samples collected from the university students. The total concentration of OPEs in the indoor dust in female dormitories (1420 ng/g) was approximately twice that in male dormitories (645 ng/g). In terms of indoor PM2.5, the highest OPE concentration was found in meeting rooms (105 ng/m3, on average), followed by chemical laboratories (51.2 ng/m3), dormitories (44.9 ng/m3), and offices (34.9 ng/m3). The total concentrations of the eight mOPEs ranged from 279 pg/mL to 14,000 pg/mL, with a geometric mean value of 1590 pg/mL. The estimated daily intake values based on the indoor dust and PM2.5 OPE samples (external exposure) were 1–2 orders of magnitude lower than that deduced from the concentration of urinary mOPEs (internal exposure), indicating that dermal contact, dust ingestion, and inhalation do not contribute significantly to OPE exposure in the general population. Moreover, additional exposure routes lead to the accumulation of OPEs in the human body.