The Short-Term Effects of Visibility and Haze on Mortality in a Coastal City of China: A Time-Series Study

Spatiotemporal distribution and lag effect of extreme temperature exposure on mortality of residents in Jiangsu, China

Background

With the ever-increasing occurrence of extreme weather events as a result of global climate change, the impact of extreme temperatures on human health has become a critical area of concern. Specifically, it is imperative to investigate the impact of extreme weather conditions on the health of residents.

Methods

In this study, we analyze the daily death data from 13 prefecture-level cities in Jiangsu Province from January 2014 to September 2022, using the distributed lag nonlinear model (DLNM) to comprehensively account for factors such as relative humidity, atmospheric pressure, air pollutants, and other factors to evaluate the lag and cumulative effects of extreme low temperature and high temperature on the death of residents across different age groups. Additionally, we utilize the Geographical Detector to analyze the effects of various meteorological and environmental factors on the distribution of resident death in Jiangsu Province. This provides valuable insights that can guide health authorities in decision-making and in the protection of residents.

Results

The experimental results indicate that both extreme low and high temperatures increase the mortality of residents. We observe that the impact of extreme low temperatures has a delayed effect, peaking after 3-5 days and lasting up to 11-21 days. In contrast, the impact of extreme high temperature is greatest on the first day, and lasts only 2-4 days.

Conclusion

Both extreme high and low temperatures increase the mortality of residents, with the former being more transient and stronger and the latter being more persistent and slower. Furthermore, residents over 75 years of age are more vulnerable to the effects of extreme temperatures. Finally, we note that the spatial distribution of resident deaths is most closely associated consistent with the spatial distribution of daily mean temperature, and there is significant spatial heterogeneity in deaths among residents in Jiangsu Province.

Haze weather and mortality in China from 2014 to 2020: Definitions, vulnerability, and effect modification by haze characteristics

Haze weather, characterized by low visibility due to severe air pollution, has aroused great public concern. However, haze definitions are inconclusive, and multicentre studies on the health impacts of haze are scarce. We collected data on the daily number of deaths and environmental factors in 190 Chinese cities from 2014 to 2020. The city-specific association was estimated using quasi-Poisson regression and then pooled using meta-analysis. We found a negative association between daily visibility and non-accidental deaths, and mortality risk sharply increased when visibility was < 10 km. Haze weather, defined as a daily average visibility of < 10 km without a limit for humidity, produced the best model fitness and greatest effect on mortality. A haze day was associated with an increase of 2.53% (95% confidence interval [CI]:1.96, 3.10), 2.84 (95% CI: 2.13, 3.56), and 2.99% (95% CI: 1.94, 4.04) in all non-accident, cardiovascular and respiratory mortality, respectively. Haze had the greatest effect on lung cancer mortality. The haze-associated risk of mortality increased with age. Severe haze (visibility <2 km) and damp haze (haze with relative humidity >90%) had greater health impacts. Our findings can help in the development of early warning systems and effective public health interventions for haze.

The impact of hazes on schizophrenia admissions and the synergistic effect with the combined atmospheric oxidation capacity in Hefei, China

OBJECTIVES

Currently, most epidemiological studies on haze focus on respiratory diseases, cardiovascular diseases, etc. However, the relationship between haze and mental health has not been adequately explored. The purpose of this study was to investigate the influence of hazes on schizophrenia admissions and to further explore the potential interaction effect with the combined atmospheric oxidative indices (O_x and O_x^wt).

METHODS

We collected 5328 cases during the cold season from 2013 to 2015 in Hefei, China. By integrating the Poisson Generalized Linear Models with the Distributed Lag Non-linear Models, the association between haze and schizophrenia admissions was evaluated. The interaction between hazes and two combined oxidation indexes was tested by stratifying hazes and O_x, and O_x^wt.

RESULTS

Haze was found to be significantly linked to an increased risk of hospitalization for schizophrenia, and a 9-day lag effect on schizophrenia (lag 3-lag 11), with the largest effect on lag 6 (RR = 1.080, 95% confidence interval (CI): 1.046-1.116). Males, females, and <40 y (people under 40 years old) were sensitive to hazes. Furthermore, in the stratified analysis, we found synergies between two combined oxidation indexes and hazes. The interaction relative risk (IRR) and relative excess risk due to interaction (RERI) between O_x and hazes were 1.170 (95% CI: 1.071-1.277) and 0.149 (95% CI: 0.045-0.253), respectively. For O_x^wt, the IRR and RERI were 1.179 (95% CI: 1.087-1.281) and 0.159 (95% CI: 0.056-0.263), respectively. It is noteworthy that this synergistic effect was significant in males and <40 y when examining the various subgroups in the interaction analysis.

CONCLUSIONS

Our findings suggest that exposure to haze significantly increases the risk of hospitalization for schizophrenia. More significant public health benefits can be obtained by prioritizing haze periods with high combined atmospheric oxidation capacity.

Has the public habituated to the haze in China?

The concept of haze habituation was proposed based on haze perception and behavior in this paper. This study employed factor analysis and Potential Conflict Index (PCI) to analyze the dimensions, degrees, and internal differences of the public's haze habituation. Then, K-means clustering algorithm was applied to classify the public into four categories. The entropy method was used to quantitatively evaluate the public's haze habituation, and the natural breakpoint method was used to grade it into five levels. Finally, an ordered logistic regression model was chosen to analyze the influencing factors of the public's haze habituation. The results indicate that: (1) The public's haze habituation can be measured from five dimensions: protective behavior, haze reduction behavior, haze attention, life impact perception, and health impact perception. The public had the same views on protective behavior, haze reduction behavior, life impact perception, and health impact perception. However, there is a wide divergence among the public on the haze attention; (2) Based on the above five dimensions, the public can be divided into the protective sensitive group, attention sensitive group, health sensitive group, and environmental protection sensitive group; (3) Generally, the public has a low haze habituation where the protective behavior, haze reduction behavior, and health impact perception are the crucial elements; (4) Gender, self-health assessment, and travel mode have a significant positive impact on the public's haze habituation, respectively. Age, the family with elders or children, and annual family income have a significant negative impact on the public's haze habituation, respectively.

Ambient NO2 is associated with Streptococcus pneumoniae-induced pneumonia in children and increases the minimum inhibitory concentration of penicillin

The present study aimed to assess the correlation between ambient air pollutants and Streptococcus pneumoniae (S. pneumoniae)-induced pneumonia in children and retrospectively reviewed the daily data regarding S. pneumoniae from children with pneumonia in a tertiary hospital of Hangzhou City, between January 1st, 2018, and December 31st, 2018. The excess risk (ER) of NO₂ with regard to the daily number of S. pneumoniae isolates obtained from the respiratory tract specimens of children with pneumonia was 13.31% (95% confidence interval [CI]: 3.12-24.51%, P = 0.010) in the single-pollutant model. An increase of 10 μg/m³ in NO₂ exposure was associated with a 23.30% increased risk for the acquisition of S. pneumoniae-induced pneumonia in children (95% CI: 2.02-49.02%; P = 0.031) according to the multi-pollutant model. The ER of NO₂ with regard to the daily number of S. pneumoniae isolates (1 μg/ml ≤ minimum inhibitory concentration (MIC) to penicillin ≤ 2 μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 15.80% (95% CI: 2.02-31.45%; P = 0.024) in the single-pollutant model. According to the multi-pollutant model, the ER of NO₂ with regard to the daily number of S. pneumoniae isolates (1 μg/ml ≤ MIC to penicillin ≤ 2 μg/ml) obtained from the respiratory tract specimens of children with pneumonia was 37.09% (95% CI: 5.70-77.81%; P = 0.018). In conclusion, ambient NO₂ is associated with S. pneumoniae-induced pneumonia in children. More importantly, NO₂ exposure is associated with the increased MICs of penicillin against S. pneumoniae from children with pneumonia.

Particulate matter pollution and emergency room visits for respiratory diseases in a valley Basin city of Northwest China

Epidemiological studies have suggested that particulate matter (PM) pollution seriously affects human health, particularly it is closely associated with respiratory diseases. The aim of this study is to quantitatively evaluate the effect of PMs (PM₁₀ and PM_2.5) on emergency room (ER) visits for respiratory diseases in Lanzhou, a valley basin city in northwest China. Based on the data of the ER visits, daily concentration of particulate matters and daily meteorological elements from January 1, 2013, to July 31, 2017, we used a generalized additive model (GAM) of time series to evaluate the exposure-response relationship between PMs and respiratory ER visits. Seasonal modified effects of PM_2.5 and PM₁₀ on different age and gender groups were also performed. Results showed that the highest incidence of respiratory diseases occurred in winter. Respiratory ER visits for the total were significantly associated with PM_2.5 (at lag 0 day) and PM₁₀ (at lag 3 days), with relative risks (RRs) of 1.042 (95%CI: 1.036 -1.047) and 1.013 (95%CI: 1.011-1.016), respectively. Effects of PM pollutants on respiratory diseases are different among different age and gender groups. Children under 15 years and the elders over 60 years were the most sensitive to PM pollution, and males were more sensitive than females. The results obtained in the current study would provide a scientific evidence for local government to make policy decision for prevention of respiratory diseases.

Short-term nitrogen dioxide exposure is associated with the spread of S. pyogenes-induced vulvovaginitis in prepubertal girls in Hangzhou, China

As a cause of vulvovaginitis in prepubertal girls, Streptococcus pyogenes (S. pyogenes) is commonly isolated from vaginal introitus swabs. Studies have identified several risk factors, but have not focused on the correlation between ambient air pollutants and S. pyogenes-induced vulvovaginitis in prepubertal girls. This study was conducted to determine whether ambient air pollutants were associated with S. pyogenes-induced vulvovaginitis in prepubertal girls. Daily data about S. pyogenes-induced vulvovaginitis in prepubertal girls from the outpatient department of Children's Hospital at the Zhejiang University School of Medicine in Hangzhou City between January 1, 2015, and December 31, 2018, were retrospectively reviewed. Ambient air pollutants in Hangzhou were measured daily. A generalized additive model (GAM) was utilized to assess the associations between daily air pollutants and S. pyogenes isolates obtained from vaginal introitus swabs of prepubertal girls. The mean daily concentration of nitrogen dioxide (NO₂) in Hangzhou City during the study period was 44.6 μg/m³ (25th-75th percentiles, 32.0-56.0 μg/m³). The GAM showed that the largest estimate effects in S. pyogenes-induced vulvovaginitis in prepubertal girls were found in NO₂ with a moving (accumulative) average on day 3. The excess risk of NO₂ in terms of the daily number of S. pyogenes isolates obtained from the vaginal introitus swabs was 14.91% (95% confidence interval [CI]: 4.85-25.94%) in the single-pollutant model. The multipollutant model revealed that an increase of 10 μg/m³ in NO₂ exposure was associated with an 18.33% increased risk for acquiring S. pyogenes-induced vulvovaginitis in prepubertal girls (95% CI: 1.21-38.35%; P < 0.05). In conclusion, short-term NO₂ exposure was strongly associated with the spread of S. pyogenes-induced vulvovaginitis in prepubertal girls.

Seasonal variation in health impacts associated with visibility in Beijing, China

Visibility has been continuously and stably observed for more than half a century, while particulate matter with an aerodynamic diameter ≤ 2.5 μm (PM_2.5) was not introduced to the national monitoring system in China until 2013. It is a scientific issue as to whether visibility can be used as an alternative to assess the health risks of air pollution in periods and areas without pollutant monitoring data. A generalized additive model (GAM) was adopted to estimate the impacts of seasonal changes in visibility on mortality in Beijing, China. Moreover, we estimated the contributions of particulate matter in the health effects of visibility by adjusting for dry extinction coefficient (β_dryext) and PM_2.5 in the model, respectively. We found that the acute health impacts of visibility varied by season, with the highest risks in winter. For respiratory mortality, the effect estimates per 1 km decrease in visibility were 0.40% (95% CI: 0.17-0.62%) in spring, 0.10% (95% CI: -0.14-0.34%) in summer, 0.27% (95% CI: 0.09-0.45%) in autumn, and 0.62% (95% CI: 0.38-0.85%) in winter. For cardiovascular mortality, the effect estimates per 1 km decrease in visibility were 0.20% (95% CI: 0.08-0.31%) in spring, 0.16% (95% CI: 0.04-0.27%) in summer, 0.25% (95% CI: 0.13-0.37%) in autumn, and 0.24% (95% CI: 0.13-0.35%) in winter. The seasonal pattern of health impacts related to visibility reflected the seasonal variations in the characteristics of air pollution emission sources and meteorological conditions that are unfavorable for pollutant dispersion. Particulate matter, particularly PM_2.5, made significant contributions to the health impacts of visibility. The results indicated that controlling pollutant emissions in winter would be of significant importance to improve air quality and mitigate the health hazard of air pollution in Beijing. Our study also provides further evidence on the feasibility of using visibility to assess the health impacts of particulate matter pollution.

The correlation between atmospheric visibility and influenza in Wuxi city, China

Influenza is an acute respiratory infectious disease that poses a threat to public health. We assessed the association between atmospheric visibility and influenza and influenza-like illness (ILI) in Wuxi city, China.Daily meteorological data, ILI activity, and influenza virus infection rates were collected between 31 December 2012 and 31 December 2017. A distributed lag non-linear model (DLNM) was used to analyze the exposure-lag-response of ILI and influenza activity and daily average visibility.A total of 12,800 cases were detected; 1046 cases (8.17%) were of Flu-A and 527 (4.12%) were of Flu-B infection. Our analysis suggested a non-linear relationship between atmospheric visibility and influenza: U-shaped for ILI, and L-shaped for Flu-A and Flu-B. Comparing low visibility (2.5 km) to ILI cases, the risk appeared between day 1 and day 2. For Flu-A, the risk appeared between days 5 and 9, whereas for Flu-B, the risk effect was much stronger and had a longer reaction delay, staying above zero until day 9. The protective effects of high visibility (14 km) on ILI and Flu-B occurred the same day or one day later. However, we found no association between high visibility and Flu-A.In conclusion, our study contributes novel evidence for the effects of atmospheric visibility on influenza. These findings are important for the development of influenza surveillance and early warning systems in Wuxi city.

Associations between air pollution and outpatient visits for allergic rhinitis in Xinxiang, China

Several epidemiological studies have investigated the adverse health effects of air pollution, but studies reporting its effects on allergic rhinitis (AR) are limited, especially in developing countries having the most severe pollution. Limited studies have been conducted in China, but their results were inconsistent. So, we conducted a time-series study to evaluate the acute effect of six air pollutants (fine particulate matter [PM_2.5], particulate matter with diameter less than 10 μm [PM₁₀], sulfur dioxide [SO₂], nitrogen dioxide [NO₂], ozone [O₃], and carbon monoxide [CO]) on hospital outpatient visits for AR in Xinxiang, China from January 1, 2015, to December 31, 2018. An over-dispersed Poisson generalized additive model adjusting for weather conditions, long-term trends, and day of the week was used. In total, 14,965 AR outpatient records were collected during the study period. Results found that each 10 μg/m³ increase in PM_2.5, PM₁₀, SO₂, NO₂, O₃, and CO corresponded to 0.70% (95% confidence interval 0.00-1.41%), 0.79% (0.35-1.23%), 3.43% (1.47-5.39%), 4.54% (3.01-6.08%), 0.97% (- 0.11-2.05%), and 0.07% (0.02-0.12%) increments in AR outpatients on the current day, respectively. In the stratification analyses, statistically stronger associations were observed with PM_2.5, PM₁₀, SO₂, NO₂, and CO for AR outpatients < 15 years of age than in those 15-65 and ≥ 65 years of age, whereas the opposite result was found with O₃. Associations between PM₁₀, SO₂, NO₂, O₃, and AR outpatients were higher in the warm season than those in the cool season. This study suggests that exposure to PM_2.5, PM₁₀, SO₂, NO₂, and CO was associated with increased AR risk and children younger than 15 years might be more vulnerable.

Cardiorespiratory responses to fine particles during ambient PM2.5 pollution waves: Findings from a randomized crossover trial in young healthy adults

BACKGROUND

PM_2.5 pollution waves (PPWs) are severe air pollution events with extremely high-level concentration of ambient PM_2.5. PPWs, such as haze days, were suggested to be associated with increased cardiopulmonary mortality and morbidity. However, the biological mechanism response to ambient PM_2.5 during PPWs is still unclear.

METHODS

A randomized crossover trial was conducted on 29 healthy young adults. Repeated health measurements were performed before, during and after two typical PPWs under filtered and sham indoor air purification, with a washout interval of at least 2 weeks. Health parameters including blood pressure (BP), pulmonary function, fractional exhaled nitric oxide (FeNO) and circulating biomarkers which reflect platelet activation, blood coagulation and systematic oxidative stress were measured.

RESULTS

Ambient PM_2.5 levels elevated apparently during PPWs. Under sham purification, significant increase in FeNO and soluble P-selectin (sP-selectin) and decreases in pulmonary function were observed from pre-PPWs period to during-PPWs period. The changes in health biomarkers as mentioned above became attenuated and insignificant under filtered condition. For instance, sP-selectin increased by 12.0% (95% CI: 3.8%, 20.8%) during-PPWs periods compared with pre-PPWs periods under sham purification, while non-significant change was observed under filtered condition. Significant associations between time-weighted personal PM_2.5 exposure and increased levels of health biomarkers including FeNO, sP-selectin, oxidized low-density lipoprotein (ox-LDL) and 8-isoprostane (8-isoPGF2α) were found.

CONCLUSION

PPWs could affect cardiopulmonary health through systematic oxidative stress, platelet activation and respiratory inflammation in healthy adults, and short-term indoor air purification could alleviate the adverse cardiopulmonary effects.

The interplay of haze characteristics on mortality in the Pearl River Delta of China

To estimate the mortality risk from haze and the modifying effects by three characteristics of haze (intensity, duration and timing), data on haze and mortality in the Pearl River Delta region from 2013 to 2016 were collected. We first estimated mortality risk during haze days compared with non-haze days. Then we classified haze into several categories by considering one or any two of the three haze characteristics together, and further calculated the mortality risks separately. The mortality risk increased 5.0% (95% confidence intervals (CI): 3.1%-6.9%) during hazy days compared with non-haze days, with larger effect for the elderly ≥ 85 years old (Excess risk (ER): 8.7%, 95% CI: 3.9%-13.6%) than other age groups. Mortality risk increased in longer haze (ER: 4.4%, 95% CI: 2.9%-6.0%) compared with shorter haze (ER: 1.9%, 95% CI: 0.7%-3.2%). The greatest effect of any two of haze characteristics was observed when haze was intense and long (ER: 4.8%, 95% CI: 3.0%-6.6%). Our study indicates that haze significantly increased mortality risk in the Pearl River Delta. The health effects of haze may be under-estimated when using a single air pollutant concentration during haze periods to assess health risk of haze events. The haze intensity, duration, and time of occurrence should be accounted for in appropriate risk assessment of haze.

Acute toxicity of intratracheal arsenic trioxide instillation in rat lungs

This study investigated the acute toxicity of different concentrations of arsenic trioxide (As₂O₃; ATO) on rat lungs. In total, 160 Wistar rats were randomly divided into the control, low‐, medium‐ and high‐dose groups, which were exposed to 0, 0.16, 1.60 and 16 μg/kg of ATO by intratracheal instillation, respectively. Samples were collected at 6, 12, 24, 48 and 72 hours after exposure and the dynamic changes indicative of acute lung toxicity were monitored. Compared with the control group, the exposure groups exhibited significant changes such as increased lung water content ratio and protein concentration in the bronchoalveolar lavage fluid, pulmonary interstitial thickening, cell membrane edema, increased inflammatory factor concentration, JNK and P38 were significantly activated, and the degree of phosphorylation was increased. Furthermore, all the changes in the exposure groups were exposure concentration‐dependent. ATO respiratory tract exposure can cause restrictive ventilatory disturbance in rats, and the degree of injury is exposure concentration‐dependent.

To investigate the acute toxicity of arsenic trioxide on lungs, 160 Wistar rats were randomly divided into the control group, low‐, medium‐ and high‐dose groups. The results showed that there were significant changes in lung water content ratio, bronchoalveolar lavage fluid protein concentration, pulmonary interstitial thickening, cell membrane edema, inflammatory factor concentration, JNK and p38 phosphorylation in the exposed group. Collectively, acute atmospheric arsenic exposure may be associated with a risk of inflammatory lung injury, which is a health concern that deserves more attention.

The effects of particulate matters on allergic rhinitis in Nanjing, China

Particulate matter pollution is a serious environmental problem. Individuals exposed to particulate matters have an increased prevalence to diseases. In the present study, we performed an epidemiological study to investigate the effects of particulate matter less than 10 μm in aerodynamic diameter (PM₁₀) and particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5) on allergic rhinitis in Nanjing, China. Daily numbers of allergic rhinitis patients (33,063 patients), PM₁₀, PM_2.5, and weather data were collected from January 2014 to December 2016 in Nanjing, China. Generalized additive models (GAM) were used to evaluate the effects of PM₁₀ and PM_2.5 on allergic rhinitis. We found that the interquartile range (IQR) increases in PM₁₀ (difference of estimates, 5.86%; 95% CI, 3.00-8.81%; P = 4.72 × 10^-5) and PM_2.5 (difference of estimates, 5.39%; 95% CI, 2.73-8.12%; P = 5.67 × 10^-5) concentrations were associated with the higher increased numbers of allergic rhinitis patients with 3-day cumulative effects in single-pollutant model. In addition, we found that the IQR increase in PM₁₀ (age ≥ 18 years: 7.37%, 3.91-10.96%, 2.14 × 10^-5; 0-17 years: 0.83%, - 4.00-5.91%, 0.740) and PM_2.5 (age ≥ 18 years: 7.00%, 3.78-10.32%, 1.40 × 10^-5; 0-17 years: 0.40%, - 4.10-5.10%, 0.866) increased the number of allergic rhinitis patients in adults, but not in children. In summary, our findings suggested that exposure to PM₁₀ and PM_2.5 was associated with the risk of allergic rhinitis.

Chinese National Air Protection Policy Development: A Policy Network Theory Analysis

Given its wide involvement in and recognition by international organizations, China has signed many international agreements and negotiations. This study verified how and the extent to which changes in exogenous factors (e.g., international agreements and negotiations) affect Chinese governmental air protection policy development. Previous studies on policy network theory have demonstrated that exogenous factors affected the development of domestic policies significantly, while in this study little evidence was found to demonstrate the influence of exogenous factors on changes in Chinese policy. Rather, internal factors have played an important role in both its development and transformation. These findings differ from study results on wealthy countries and other developing districts. This study then explores the causes of substandard policy outcomes. To probe this further, policy network theory is applied to explain the gap between the guiding principle of central government's policies and local implementation in actual practice. By analyzing the strategies of policy actors and specific rules in current Chinese context, the associated limitations and obstacles in the process of policy-making and implementation can be explained from the aspect of bureaucratic system, energy market running mechanism and others. This paper recommends alterations in the current policy and structure based on these findings.