Estimating elemental composition of personal PM2.5 by a modeling approach in two megacities, China.

Personal exposure to PM2.5, and the elemental composition therein, may vary greatly from ambient measurements at fixed monitoring sites. Here, we characterized the differences between personal, indoor, and outdoor concentrations of PM2.5-bound elements, and predicted personal exposures to 21 PM2.5-bound elements. Personal-indoor-outdoor PM2.5 filter samples were collected for five consecutive days across two seasons from 66 healthy non-smoking retired adults in Beijing (BJ) and Nanjing (NJ), China. Personal element-specific models were developed using liner mixed effects models and evaluated by R2 and root mean square error (RMSE). The mean (SD) concentrations of personal exposures varied by element and city, ranging from 2.5 (1.4) ng/m3 for Ni in BJ to 4271.2 (1614.8) ng/m3 for S in NJ. Personal exposures to PM2.5 and most elements were significantly correlated with both indoor and outdoor (except Ni in BJ) measurements, but frequently exceeded indoor levels and fell below outdoor levels. Indoor and outdoor PM2.5 elemental concentrations were the strongest determinants of most personal elemental exposures, with RM2 ranging from 0.074 to 0.975 for indoor and from 0.078 to 0.917 for outdoor levels, respectively. Home ventilation conditions (especially window opening behavior), time-activity patterns, meteorological factors, household characteristics, and season were also key factors influencing personal exposure levels. The final models accounted for 24.2 %-94.0 % (RMSE: 0.135-0.718) of the variance in personal PM2.5 elemental exposures. By incorporating these crucial determinants, the modeling approach used here can improve PM2.5-bound elemental exposure estimates and better associate compositionally dependent PM2.5 exposures and health risks.

Personal exposure to PM2.5 in different microenvironments and activities for retired adults in two megacities, China.

Microenvironmental concentrations and time-activity patterns influence personal exposure to fine particulate matter (PM2.5). However, the variations and contributions of PM2.5 exposures from various microenvironments (MEs) and activities remain unclear. In this study, gravimetrically corrected real-time personal PM2.5 measurements were collected during routine activities in different MEs from 66 non-smoking retired adults. Exposure data were collected for five consecutive days over two seasons in Nanjing (NJ) and Beijing (BJ), China. Measured PM2.5 concentrations varied substantially both between and within different MEs and activities. The highest average concentrations were observed in restaurants (NJ: mean 192 µg/m3, SD 242 µg/m3; BJ: mean 91 µg/m3, SD 79 µg/m3) and were associated with sources such as passive smoking and cooking emissions. Overall, PM2.5 concentrations in different MEs and activities were moderately to highly correlated with outdoor PM2.5 concentrations (Spearman's r = 0.51-0.97) except in restaurants and during passive smoking. The at-home ME contributed approximately 85 % of the total PM2.5 exposure, corresponding to the participants spending about 87 % of their time there. The majority of household exposures occurred during sleeping, cooking, and other home-based activities. Transportation accounted for <5 % of total exposure. Our results indicate that improving indoor air quality, especially residential indoors, is important to reduce personal exposure to PM2.5.

The influencing factors of health hazards of benzo[a]pyrene in cigarette mainstream smoke: The example of one brand in Beijing.

INTRODUCTION: The study focused on the influence of tar concentrations, smoking regimen, and smoking behavior, on benzo[a]pyrene (B[a]P) emission from cigarette mainstream smoke and related health hazards to determine the key factors influencing B[a]P reduction and protection of the smoker's health. METHODS: A locally popular brand of cigarettes in Beijing was selected with tar concentrations of 1, 3, 5, 8, 10, and 11 mg/cigarette. Two different machine smoking regimens, the Canada Intense (HCI) regimen and the International Organization for Standardization (ISO) regimen, were adopted to collect the cigarette mainstream smoke. The B[a]P emission concentrations were then measured by gas chromatography and mass spectrum. RESULTS: The average B[a]P emission was 8.14-17.6 ng/cigarette for the HCI regimen and 0.92-3.46 ng/cigarette for the ISO regimen. As expected, the tar concentrations and B[a]P emissions exhibited a positive relation in both the HCI and ISO regimens, the cancer risk and non-cancer risk increased with an increase in tar concentrations for both the ISO and HCI regimens, and the smoking behavior also affected the B[a]P emissions with a tendency of VB (ventilation blocking) > HVB (half ventilation blocking) > DP (deep puff), under the same smoking regimen. Under the same conditions, the cancer risk and non-cancer risk in men were 1.19 and 1.11 times, respectively, higher than in women. CONCLUSIONS: The smoking regimen influences the B[a]P emission relatively more than the cigarette tar concentration and smoking behavior. The cancer risk and non-cancer risk are higher in men than in women that possibly due to longer smoking duration and greater smoking intensity.

Air Pollution Health Impact Monitoring and Health Risk Assessment Technology and Its Application - China, 2006-2019.

Air pollution is a significant risk factor contributing to the burden of disease in China. Health risk assessment and management are important to reduce the impact of air pollution on public health. To help formulate standardized health risk assessment techniques, a series of studies were conducted from 2006 to 2019. Through systematic review, study of molecular mechanisms, epidemiological investigation, and health effect monitoring, the overall project established a monitoring and evaluation indicator system, a comprehensive information platform, software for automatic data cleaning, and standardized health risk assessment techniques. Technical specifications have been issued by the National Health Commission for promoting health risk assessments across China. This paper introduces the project, the research approach, its main research accomplishments, innovations, and public health significance, and describes directions for further research.

Risk factors and on-site simulation of environmental transmission of SARS-CoV-2 in the largest wholesale market of Beijing, China.

From June 11, 2020, a surge in new cases of coronavirus disease 2019 (COVID-19) in the largest wholesale market of Beijing, the Xinfadi Market, leading to a second wave of COVID-19 in Beijing, China. Understanding the transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the personal behaviors and environmental factors contributing to viral transmission is of utmost important to curb COVID-19 rise. However, currently these are largely unknown in food markets. To this end, we completed field investigations and on-site simulations in areas with relatively high infection rates of COVID-19 at Xinfadi Market. We found that if goods were tainted or personnel in market was infected, normal transaction behaviors between sellers and customers, daily physiological activities, and marketing activities could lead to viral contamination and spread to the surroundings via fomite, droplet or aerosol routes. Environmental factors such as low temperature and high humidity, poor ventilation, and insufficient hygiene facilities and disinfection practices may contribute to viral transmission in Xinfadi Market. In addition, precautionary control strategies were also proposed to effectively reduce the clustering cases of COVID-19 in large-scale wholesale markets.

Source specific PM2.5 associated with heart rate variability in the elderly with coronary heart disease: A community-based panel study.

There is increasingly concern that PM2.5 constituents play a significant role in PM2.5-related cardiovascular outcomes. However, little is known about the associations between specific constituents of PM2.5 and risk for cardiovascular health. To evaluate the exposure to specific chemicals of PM2.5 from various sources and their cardiac effects, a longitudinal investigation was conducted with four repeated measurements of elderly participants' HRV and PM2.5 species in urban Beijing. Multiple chemicals in PM2.5 (metals, ions and PAHs) were characterized for PM2.5 source apportionment and personalized exposure assessment. Five sources were finally identified with specific chemicals as the indicators: oil combustion (1.1%, V & PAHs), secondary particle (11.3%, SO42- & NO3-), vehicle emission (1.2%, Pd), construction dust (28.7%, Mg & Ca), and coal combustion (57.7%, Se & As). As observed, each IQR increase in exposure to oil combustion (V), vehicle emission (Pd), and coal combustion (Se) significantly decreased rMSSD by 13.1% (95% CI: -25.3%, -1.0%), 27.4% (95% CI: -42.9%, -7.6%) and 24.7% (95% CI: -39.2%, -6.9%), respectively, while those of PM2.5 mass with decreases of rMSSD by 11.1% (95% CI: -19.6%, -1.9%) at lag 0. Elevated exposures to specific sources/constituents of PM2.5 disrupt cardiac autonomic function in elderly and have more adverse effects than PM2.5 mass. In the stratified analysis, medication and gender modify the associations of specific chemicals from variable sources with HRV. The findings of this study provide evidence on the roles of influential constituents of ambient air PM2.5 and their sources in terms of their adverse cardiovascular health effects.

Determinants of personal exposure to fine particulate matter in the retired adults - Results of a panel study in two megacities, China.

This study aimed to investigate the relationship between outdoor, indoor, and personal PM2.5 exposure in the retired adults and explore the effects of potential determinants in two Chinese megacities. A longitudinal panel study was conducted in Nanjing (NJ) and Beijing (BJ), China, and thirty-three retired non-smoking adults aged 43-86 years were recruited in each city. Repeated measurements of outdoor-indoor-personal PM2.5 concentrations were measured for five consecutive 24-h periods during both heating and non-heating seasons using real-time and gravimetric methods. Time-activity and household characteristics were recorded. Mixed-effects models were applied to analyze the determinants of personal PM2.5 exposure. In total, 558 complete sets of collocated 24-h outdoor-indoor-personal PM2.5 concentrations were collected. The median 24-h personal PM2.5 exposure concentrations ranged from 43 to 79 µg/m3 across cities and seasons, which were significantly greater than their corresponding indoor levels (ranging from 36 to 68 µg/m3, p < 0.001), but significantly lower than outdoor levels (ranging from 43 to 95 µg/m3, p < 0.001). Indoor and outdoor PM2.5 concentrations were the strongest determinants of personal exposures in both cities and seasons, with RM2 ranging from 0.814 to 0.915 for indoor and from 0.698 to 0.844 for outdoor PM2.5 concentrations, respectively. The personal-outdoor regression slopes varied widely among seasons, with a pronounced effect in BJ (NHS: 0.618 ± 0.042; HS: 0.834 ± 0.023). Ventilation status, indoor PM2.5 sources, personal characteristics, and meteorological factors, were also found to influence personal exposure levels. The city and season-specific models developed here are able to account for 89%-93% of the variance in personal PM2.5 exposure. A LOOCV analysis showed an R2 (RMSE) of 0.80-0.90 (0.21-0.36), while a 10-fold CV analysis demonstrated a R2 (RMSE) of 0.83-0.90 (0.20-0.35). By incorporating potentially significant determinants of personal exposure, this modeling approach can improve the accuracy of personal PM2.5 exposure assessment in epidemiologic studies.

The impact of heating season factors on eight PM2.5-bound polycyclic aromatic hydrocarbon (PAH) concentrations and cancer risk in Beijing.

In 2015, 443 atmospheric PM2.5 samples were collected at five sampling sites in Beijing. The concentrations of PM2.5-bound PAH8 (Chr, BaA, BbF, BkF, B[a]P, DBA, BghiP, and IND) were determined via high performance liquid chromatography (HPLC). The annual concentration of PM2.5-bound PAH8, lifetime cancer risk, and the increasing value due to heating season factors (heating and meteorological conditions) were analyzed. The results showed that the sum concentration of PM2.5-bound PAH8 during heating season was 72.6 ng/m3 and higher than the non-heating season concentration of 4.77 ng/m3. The annual concentration was 10.6 ng/m3, which increased 5.83 ng/m3 due to heating season factors. The B[a]P annual concentration was 1.67 ng/m3 and higher than the limit of 1 ng/m3, which was 15.2 times that of non-heating season. Diesel vehicles and gasoline vehicles were the primary PAH8 sources during non-heating season, while the mixed sources of diesel vehicles, gasoline vehicles, and combustion were the dominant PAH8 sources during heating season. The most significant health hazard pollutant was B[a]P, which accounted for 72%, 74%, and 69% of the B[a]P equivalent concentration (B[a]Peq) of PAH8 during heating season, non-heating season, and throughout 2015, respectively. The lifetime cancer risk was 2.67 × 10-6, which increased 1.36 × 10-6 due to heating season factors. Therefore, heating season factors nearly doubled the annual concentration of PM2.5-bound ∑PAH8 and lifetime cancer risk. The results indicated that to protect human health, it is very important to control PM2.5-bound ∑PAH8 emissions during heating season, especially B[a]P emissions.

Pollution characteristics of ambient PM2.5-bound benzo[a]pyrene and its cancer risks in Beijing.

The purpose of this study was to reveal the pollution characteristics of ambient PM2.5-bound benzo[a]pyrene (B[a]P) in Beijing and to assess the lifetime cancer risk from respiratory pathway exposure. The average daily dose was evaluated by the annual concentrations of ambient PM2.5-bound B[a]P, combined with Chinese human exposure factors and the age sensitivity factors. The 70-year lifetime cancer risks of different groups were assessed by the exposure assessment and stochastic analysis method recommended by California Environmental Protection Agency. The groups were divided by age and gender. The results showed that the ambient PM2.5-bound B[a]P concentration during the cold season was 15.7 times greater than that during the warm season in Beijing. The annual average concentrations of PM2.5-bound B[a]P in outdoors and indoors were 1.67 ng/m3 and 1.04 ng/m3, respectively, which exceeded the limit of Chinese National Ambient Air Quality Standard. The cancer risks of PM2.5-bound B[a]P in males, females, and the general population were 9.085 × 10-6, 8.050 × 10-6, and 8.740 × 10-6, respectively. The cancer risk constituent ratios of ambient PM2.5-bound B[a]P in early life (≤16 years of age) for males, females, and the general population were 70.9%, 71.4%, and 71.3%, respectively. The males' cancer risk of PM2.5-bound B[a]P in Beijing was higher than that of the females. The early life cancer risk exposure to PM2.5-bound B[a]P should be paid more attention.

[Determination of gaseous nicotine in ambient air by high performance liquid chromatography].

OBJECTIVE: To establish the determination of gaseous nicotine in ambient air using high performance liquid chromatography. METHODS: The nicotine samples of ambient air were collected by passive air samples. The Sample film was sonicated, extracted, evaporated with nitrogen sweeping, and dissolved with the mobile phase. Nicotine was separated by C18 reversed-phase column, examined by ultraviolet detector, quantified by peak area and qualitatively measured by its retentive time. RESULTS: The limit of detection and the limit of quantification is 30 ng/mL, 101 ng/mL, respectively. The precision is characterized by RSD in the rage 0.24% -2.62%. The average recovery of sample is in the rage of 82.0% -107.2%. The samples can be kept more than 11 days in the dry state of room temperature after sealing. CONCLUSION: The method is suitable for the determination of nicotine concentration in public places air.

[Simultaneous determination of 31 volatile organic compounds in decorated rooms by two-stage thermal desorption-capillary gas chromatography].

OBJECTIVE: To establish the monitoring method to simultaneously measure 31 volatile organic compounds in decorated rooms using two-stage thermal desorption-capillary gas chromatography. METHODS: Using the Tenax TA absorption tube to sample, and subsequently desorbed and analyzed by two-stage thermal desorption capillary gas chromatography column, and measured by FID detector. RESULTS: 31 volatile organic compounds can be well separated in the chromatography column. In the experiment, the relative standard deviations of the reoccuring of each compound were within 10%. All the correlation coefficients of linear regression equation were greater than 0.99. The lowest detection limit can reach the concentration level of 1 ng/microl, and the recoveries were 83.2% - 106%. CONCLUSION: The method is applicable to determination of 31 volatile organic compounds in the decorated rooms simultaneously.

[TRPV1 UTR-3 polymorphism and susceptibility of childhood asthma of the Han Nationality in Beijing].

OBJECTIVE: To explore TRPV1 UTR-3 polymorphism and susceptibility of childhood asthma of Han Nationality in Beijing. METHODS: 177 asthmatics, 44 atopy, and 151 control children less than 14-years-old were enrolled in case-control study, and all subjects were investigated by ISSAC questionnaires. Dominant, recessive, co-dominant, over-dominant, and log additive model were used to do genotype analysis, and LD analysis and haplotypes of SNPs were tested by Haploview 4.1. Hardy-Weinberg equilibrium test, Person chis-square test, linkage disequilibrium analysis, and logistic analysis were performed by SAS 9.1 software to determine the association between polymorphisms of TRPV1 and susceptibility of childhood asthma. RESULTS: Polymorphisms were found in rs402369, rs4790521, and rs4790522, Hardy-Weinberg P > 0.05. As to allele frequencies, frequency of SNP rs4790521 T/C in asthmatics were significantly increased (P < 0.05), no significant difference were found in MAF of rs402369 and rs4790522 (P > 0.05). Genotype analysis showed that rs4790521 C/C and rs4790522 A/C were associated with childhood asthma (P < 0.05), and odd ratios were 2.94 (1.32 - 6.53) and 0.588 (0.376 - 0.920) respectively. LD were found between rs4790521 and rs4790522, 3 haplotypes were built. Adjusted by age, gender, parent asthma history, and smoking exposure, logistic stepwise analysis showed that MAF of rs4790521, allozygote C/C of rs4790521, and haplotype C/C were associated with susceptibility to childhood asthma in Chinese Han Nationality in Beijing (P < 0.05). CONCLUSION: TRPV1 UTR-3 polymorphisms could be associated with the susceptibility to childhood asthma of Han Nation a city in Beijing.

[Influence of PAHs exposure and GSTT1, GSTM1 genotypes on urinary 1-OHP as exposure biomarker].

OBJECTIVE: To study the influence of polycyclic aromatic hydrocarbons (PAHs) exposure (ambient concentration and smoking) and GSTT1, GSTM1, genotypes on urinary 1-OHP as exposure biomarker. METHODS: 51 Cops who working outside were selected as study group, 48 Cops who working in office were selected as control Group. The ambient concentrations of PAHs both of two circumstances and the urinary 1-OHP of subjects were measured. The ambient concentrations of PAHs and the urinary 1-OHP were determined by high performance liquid chromatography (HPLC). The GSTT1, GSTM1 genotypes were determined by PCR. RESULTS: The ambient concentrations of PAHs in the study group and the control group were 20.85 ng/m3 and 12.79 ng/m3 respectively. There were not significant difference in urinary 1-OHP among the persons who had the deference GSTT1, GSTM1, genotypes and the same smoking habits in the study group and the control group. The urinary 1-OHP concentrations of the study group were higher than those of the control group when they had the same genotypes for non-smokers. Smoking stratified analysis showed that urinary 1-OHP concentrations of smokers were higher than those of non-smokers, the urinary 1-OHP concentrations of smokers in control group were higher than those of the non-smokers in study group. CONCLUSION: The ambient PAHs concentration and smoking could be the important factors generated the urinary 1-OHP concentration. While the levels of ambient PAHs were low, the smoking could change more prominent. The GSTT1, GSTM1 genotypes could not be the major influential factors.

A pilot study on using urinary 1-hydroxypyrene biomarker for exposure to PAHs in Beijing.

To study whether the urinary 1-hydroxypyrene (1-OHP) could be the biomarker of atmospheric PAHs, a small-scale pilot study was carried out on the relation of 1-OHP vs PAHs with the traffic policemen in Beijing of smokers and nonsmokers to be subgroups in both the exposure and control groups. Both the PAHs and 1-OHP were analyzed with high performance liquid chromatography (HPLC). The ambient concentrations of PAHs were different at the different sites (the average sum of PAHs (TPAH) were 12.36, 16.27, 18.37 ng/m(3) at the suburban residential, police station and high traffic area, respectively.), but considerably lower than the personal-exposure concentrations (the average TPAH were 65.84 and 47.28 ng/m(3) for patrol cars and inspection station, respectively). Pyrene was correlated well with BaP and the summed PAHs (TPAH), with the correlation coefficients (R) of 0.79, 0.87 for ambient level and 0.92, 0.96 for personal exposure, respectively. The average of 1-hydroxypyrene of smokers and nonsmokers were 0.39, 0.15 mumol/mol creatinine in control group and 0.57, 0.33 mumol/mol creatinine in exposure group, respectively. The better correlation of pyrene to BaP and TPAH especially for personal exposure samples indicated that the probability of urinary 1-hydroxypyrene, the metabolite of pyrene, to be the biomarker of total PAH. Nonsmokers in the exposure and control groups had indistinguishable levels of 1-OHP, presumably because the ambient levels of pyrene were so similar (the average were 3.25, 3.20 ng/m(3) at the police station and high traffic area, respectively.). Smokers in the control group had significantly higher 1-OHP than that of the nonsmokers, but showed indistinguishable differences in the exposure group. These results suggested that urinary 1-OHP could be a biomarker of PAHs only when the level of PAHs was at a relatively higher level. Smoking as an important influencing factor need to be controlled carefully.

[Effects of formaldehyde on the activity of superoxide dismutases and glutathione peroxidase and the concentration of malondialdehyde].

This review focus on the effects of formaldehyde on the activity of superoxide dismutases (SOD), glutathione peroxidase (GSH-Px) and the concentration of malondialdehyde (MDA) in recent years. It is showed formaldehyde having effect on lipid peroxidation by many studies of animal experiment and occupational group, it can decrease the activity of SOD and GSH-Px, increase the concentration of MDA, there are dose-response relationship between those lipid peroxidation index and the concentration of formaldehyde too. In future study, the animal experiment and the people's late effect of low dose formaldehyde exposure should be pay more attention.