Short-term effects of ozone air pollution on hospital admissions for myocardial infarction: A time-stratified case-crossover study in Taipei

Association between short-term ozone exposure and allergic conjunctivitis in China: A multi-city case-crossover study

Short-term exposure to ozone has been linked to multiple allergic diseases, but the relationship between ozone exposure and allergic conjunctivitis (AC) remains unclear. This study aimed to investigate the association between short-term exposure to ozone and the risk of AC. We conducted a time-stratified case-crossover study across five Chinese cities from 2014 to 2022. Daily outpatient visit records for AC were identified in five hospitals using either the diagnosis name or ICD-10 code H10.1. Data on air pollution and meteorological conditions were also collected. We first examined the city-specific association between short-term ozone exposure and AC using conditional logistic regression. A random-effects meta-analysis was then conducted to obtain overall estimates. During the study period, 130,093 outpatient visits for AC occurred, with 58.8% (76,482) being male and 41.2% (53,611) female. A one-standard-deviation (SD) increase in ozone was associated with an 8.3% increase (95% CI: 3.8%, 13.0%) in AC outpatient visits. Similar positive associations were observed when adjusting for other pollutants (PM2.5, CO, SO2 and NO2) in two-pollutant and multi-pollutant models. Furthermore, the positive association remained consistent when using mixed-effects regression models or further adjusting for meteorological conditions. In addition, no effect modification of the AC-ozone association by sex, age and season was apparent. This study provides evidence supporting a positive association between short-term ozone exposure and AC risk in China. This highlights the potential value of mitigating ozone pollution to reduce the risk of ocular surface disorders.

Association Between Exposure to Ozone (O3) and the Short-Term Effect on Tuberculosis Outpatient Visits: A Time-Series Study in 16 Cities of Anhui Province, China

Introduction

Evidence has shown that air pollutant exposure plays a vital role in the progression of tuberculosis (TB). The aim of this research was to assess the short-term effects of ozone (O₃) exposure and TB outpatient visits in 16 prefecture-level cities of Anhui, China, 2015-2020.

Methods

Distributed lag nonlinear model (DLNM), Poisson generalized linear regression model and random effects model were applied in this study. The effects of different age and gender on TB were investigated by stratified analysis, and then we performed sensitivity analyses to verify the stability of the results.

Results

A total of 186,623 active TB cases were registered from January 1, 2015 to December 31,2020 in Anhui. The average concentration of ozone is 92.77 ± 42.95 μg/m³. The maximum lag-specific and cumulative relative risk (RR) of TB outpatient visits was 1.0240 (95% CI: 1.0170-1.0310, lag 28 days) for each 10 µg/m³ increase in O₃ in the single-pollutant model. Estimation for 16 prefecture-level cities indicated that the strong association between O₃ and the risk of TB outpatient visits was in tongling (RR = 1.0555, 95% CI: 1.0089-1.1042), Suzhou (RR = 1.0475, 95% CI: 1.0268-1.0687), wuhu (RR = 1.0358, 95% CI: 1.0023-1.0704). Stratified analysis showed that the health effects of ozone exposure remained significant in male and older adults, and there was no significant association between exposure to ozone in children and adolescents and the risk of tuberculosis.

Discussion

We found that ozone exposure increases the risk of TB infection in outpatient patients, with males and the elderly being more susceptible, and it is necessary for government departments to develop targeted publicity and prevention measures in response to the local air quality conditions.

Ambient ozone exposure and hospitalization for substance abuse: A time-stratified case-crossover study in Taipei

A number of studies investigating the possibility that air pollutant exposures increases the risk of adverse effects on mental health including frequency of suicide and depression, is a major growing public health concern. Human data demonstrated that exposure to various ambient air contaminants including ozone (O₃) adversely affected nervous system functions. It is also well-established that substance abuse produces central nervous system dysfunctions with resultant increase in suicide rates. However, the role of substance abuse in combination with O₃ exposure on mental health remained to be determined. The aim of this investigation was to conduct a time-stratified case-crossover study to examine the possible correlation between short-term ambient O₃ exposure and daily hospital admissions for substance abuse, including alcohol dependence syndrome and non-dependent abuse of drugs, in Taipei from 2009 to 2013. In our single pollutant model, a 35% rise in interquartile (IQR) O₃ levels on cool days and a 12% elevation on warm days was associated with increase in mental health hospitalizations. In our two-pollutant models, O₃ remained significantly associated with elevated number of hospitalizations after adding any one of possible air pollutants, PM₁₀, PM_2.5, SO₂, NO₂, and CO, to our model on cool and warm days. Data suggested that temperature may affect the association between outdoor ambient air O₃ exposure and enhanced risk of hospitalization for substance abuse. Further study is needed to better understand these findings.

Short-term effects of main air pollutants exposure on LOS and costs of CVD hospital admissions from 30,959 cases among suburban farmers in Pingliang, Northwest China

BACKGROUND

Although cardiovascular disease (CVD) has been the major contributor to global mortality and disability especially in undeveloped and developing countries/areas with severer air pollutions, studies are quite limited and evidence is insufficient of short-term main air pollutants exposure on health burden of CVD hospital admissions in those regions particularly through direct costs.

METHOD

Based on an analysis of 30,959 CVD hospital admissions among suburban farmers from 2018 to 2019 through multiple linear regression (MLR), our study evaluated the impact of main air pollutants (PM_2.5, PM₁₀, SO₂, CO, NO₂ and O₃) exposure on number of cases, length of stay (LOS) and costs of CVD hospital admissions in Pingliang, China.

RESULTS

Concentration of SO₂ and O₃ rising from a low level was found to lower the costs, LOS and daily cases of CVD hospital admissions and PM_2.5, PM₁₀, CO and NO₂ were found to aggravate the burden. Besides, the NO₂ could put more economic stress on those CVD patients in Pingliang (China) which implies that some improvements could be done on public medical insurance policy and benefit local suburban farmers by strengthening the supports on specific drugs and therapies.

CONCLUSIONS

More efforts should be made to lower the concentration of air pollution by coordinated control managements even in a low-level scenario. Concentration levels and interactions between main air pollutants may play an important role in air pollution-induced CVD health burden. Future research is needed to explore more evidence in different areas, especially with low-level SO₂ effects.

Short term exposure to ambient air pollutants and cardiovascular emergency department visits in Mexico city

Available data on the acute cardiovascular effect of ambient air pollution (AAP) in Latin America is limited considering that over 80% of its 1 billion inhabitants live in urban settlements with poor air quality. The study aim was to evaluate the association between Cardiovascular Emergency Department Visits (CEDVs) and AAP in Mexico City from 2016 to 2019 using generalized additive models with distributed lags to examine the percentage change of CEDVs and a backward approach of time-series model to calculate attributable fractions. A total of 48,891 CEDVs were recorded in a period of 1019 days. We estimated a significant percentage increase for each 10 μg/m³ of PM₁₀ at Lag0-5 (2.8%, 95%CI 0.6-5.0), PM_2.5 at Lag0-6 (3.7%, 95%CI 0.1-7.6), O₃ at Lag0-5 (1.1%, 95%CI 0.2-2.0), NO₂ at Lag0-4 (2.5%, 95%CI 0.3-4.7) and for each 1 mg/m³ of CO at Lag0 (6.6%, 95%CI 0.3-13.2). Overall, 10.3% of CEDVs in Mexico City may be related to PM¹⁰ exposure, 9.5% to PM_2.5, 10.3% to O₃, 11% to NO₂ and 5.7% to CO. AAP significantly increase cardiovascular morbidity impacting on emergency medical services.

Relationship between fine particulate air pollution and hospital admissions for depression: a case-crossover study in Taipei

There are few apparent studies regarding the association between fine particulate matter (PM_2.5) air pollution and development of depression. Data obtained from epidemiological studies are inconsistent and controversial. The aim of this case-crossover study was to examine the association between short-term exposure to PM_2.5 alone and in combination with other pollutants and frequency of hospitalizations for depression from 2009 to 2013 in Taipei, Taiwan. In the single pollutant model without adjustment for other pollutants, 17% and 4% increase in admissions attributed to depression correlated with interquartile range (IQR) rise in PM_2.5 levels was noted on warm and cool days, respectively. Data were also analyzed using two-pollutant models and it was found that on warm days, the association continued to be significant after including one of the following pollutants: sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃) or carbon monoxide (CO). On cool days, the significance was lost. In conclusion, the relationship between ambient outdoor PM_2.5 exposure and rates of hospitalization for depression appeared to be temperature dependent in Taipei. Further research is needed to verify these observations as well as to distinguish the relative contributions of PM_2.5 and temperature to development for hospital admissions for depression.

Emergency hospital admissions for cardiovascular diseases attributed to air pollution in Tehran during 2016-2019

The burden of five main air pollutants, including CO, O3, NO2, SO2, and PM2.5, on the emergency department visits (EDVs) during January 2016-December 2019 due to all cardiovascular diseases was assessed in Tehran by using a time-series model. The pollutants data were collected from Iran Department of Environment including 10 air pollution monitoring stations for the period of our study. Cumulative relative risk and attributable number/fraction were calculated for each pollutants by a Quasi-Poisson time-series regression and distributed lag non-linear model (DLNM). The maximum lag was set to 14 days because harvesting effect is more likely happened during few days. We used percentile 25 as reference value in order to calculate cumulative relative risk and attributable fraction. About 69,000 patients with cardiovascular symptoms have been admitted into the hospital during 4 years. The cumulative relative risk during the 14 days was 1.13 (1.01, 1.26), 1.15 (1.02, 1.29), and 1.08 (1.01, 1.18) for CO, NO2, and PM2.5, respectively. The numbers attributed to all values of CO were more than others; about 3800 EDVs were significantly attributed to CO, of which over 3000 were significantly attributed to high values of the pollutant. Low values of all pollutants were, not surprisingly, responsible for low number of EDVs. PM2.5, CO, and NO2 were responsible to considerable attributable number of EDVs. Our study emphasizes the need for local authorities to establish a program to reduce the air pollution in Tehran.

Acute effects of ambient air pollution on clinic visits of college students for upper respiratory tract infection in Wuhan, China

Ambient air pollutants have been linked to adverse health outcomes, but evidence is still relatively rare in college students. Upper respiratory tract infection (URTI) is a common disease of respiratory system among college students. In this study, we assess the acute effect of air pollution on clinic visits of college students for URTI in Wuhan, China. Data on clinic visits due to URTI were collected from Wuhan University Hospital, meteorological factors (including daily temperature and relative humidity) provided by Wuhan Meteorological Bureau, and air pollutants by Wuhan Environmental Protection Bureau. In the present study, generalized additive model with a quasi-Poisson distribution link function was used to examine the association between ambient air pollutants (fine particulate matter (PM2.5), particulate matter (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3)) and the daily number of clinic visits of college students for URTI at Wuhan University Hospital in Wuhan, China. In the meantime, the model was adjusted for the confounding effects of long-term trends, seasonality, day of the week, public holidays, vacation, and meteorological factors. The best degrees of free in model were selected based on AIC (Akaike Information Criteria). The effect modification by gender was also examined. A total of 44,499 cases with principal diagnosis of URTI were included from January 1, 2016, to December 31, 2018. In single-pollutant models, the largest increment of URTI visits were found at lag 0 day in single-day lags, and the effect values in cumulative lags were greater than those in single-day lags. PM2.5 (0.74% (95%CI: 0.05, 1.44)) at lag 0 day, PM10 (0.61% (95%CI: 0.12, 1.11)) and O3 (1.01% (95%CI: 0.24, 1.79)) at lag 0-1 days, and SO2 (9.18% (95%CI: 3.27, 15.42)) and NO2 (3.40% (95% CI:1.64, 5.19)) at lag 0-3 days were observed to be strongly and significantly associated with clinic visits for URTI. PM10 and NO2 were almost still significantly associated with URTI after controlling for the other pollutants in our two-pollutant models, where the effect value of SO2 after inclusion of O3 appeared to be the largest and the effects of NO2 were also obvious compared with the other pollutants. Subgroups analysis demonstrated that males were more vulnerable to PM10 and O3, while females seemed more vulnerable to exposure to SO2 and NO2. This study implied that short-term exposure to ambient air pollution was associated with increased risk of URTI among college students at Wuhan University Hospital in Wuhan, China. And gaseous pollutants had more negative health impact than solid pollutants. SO2 and NO2 were the major air pollutants affecting the daily number of clinic visits on URTI, to which females seemed more vulnerable than males.

Change in risk of hospital admissions for ischemic heart disease after the implementation of a mass rapid transit system in Taipei

Numerous epidemiologic studies demonstrated an association between an increase in levels of fine particles (particulate matter less than 2.5 um in diameter, PM_2.5) and elevation in the number of hospital admissions for cardiovascular diseases. Air pollution levels including PM_2.5 clearly decreased in Taipei City after the mass rapid transit (MRT) system began operations in 1996. The aim of this study was to investigate the extent of changes in the risk of daily hospital admissions for ischemic heart disease (IHD) over a 17-year period after the installation of a MRT system in Taipei. The full study was divided into Period 1 (1997-2000), total track length 65.1 km; Period 2 (2001-2008), total track length 75.8 km; and Period 3 (2009-2013), total track length 121.3 km. A time-stratified case-crossover analysis was conducted to estimate relative risk (RR) of hospital admissions for IHD for each 10 ug/m³ increase in PM_2.5 for different periods. On cool days, the associated RR of IHD for Period 3 was consistently lower compared to period 2 in both our single- and two-pollutant models. However, the daily risk for IHD admissions was found to be significantly higher for period 3 compared to period 2 in our single-pollutant model and in our two-pollutant models (PM_2.5+ SO₂) on warm days. The basis for this difference is unknown. Data suggests that an MRT system may provide substantial health benefits, a finding that may be helpful to urban communities, urban planners, and public health specialists.

Air Pollution and Emergency Hospital Admissions—Evidences from Lisbon Metropolitan Area, Portugal

The relevance of air pollution in the public health agenda has recently been reinforced—it is known that exposure to it has negative effects in the health of individuals, especially in big cities and metropolitan areas. In this article we observed the evolution of air pollutants (CO, NO, NO2, O3, PM10) emissions and we confront them with health vulnerabilities related to respiratory and circulatory diseases (all circulatory diseases, cardiac diseases, cerebrovascular disease, ischemic heart disease, all respiratory diseases, chronic lower respiratory diseases, acute upper respiratory infections). The study is supported in two databases, one of air pollutants and the other of emergency hospital admissions, in the 2005–2015 period, applied to the Lisbon Metropolitan Area. The analysis was conducted through Ordinary Least Squares (OLS) regression, while also using semi-elasticity to quantify associations. Results showed positive associations between air pollutants and admissions, tendentially higher in respiratory diseases, with CO and O3 having the highest number of associations, and the senior age group being the most impacted. We concluded that O3 is a good predictor for the under-15 age group and PM10 for the over-64 age group; also, there seems to exist a distinction between the urban city core and its suburban areas in air pollution and its relation to emergency hospital admissions.

Association between ozone air pollution levels and hospitalizations for depression in Taipei: a time-stratified case-crossover study

Epidemiologic studies reported an association between exposure to ambient air pollutants and increased mortality rate attributed to suicide and suicide attempts. The investigation sought to determine whether there is an association between short-term ambient ozone (O₃) level exposure and daily hospital admissions for depression in Taipei from 2009 to 2013 using a time-stratified case-crossover design. In our single-pollutant model (with no adjustment for other pollutants), the % increase in daily hospital admissions for depression was 12% on warm days and 30% on cool days, per interquartile range (IQR) rise in O₃ levels, respectively. Ozone levels were significantly correlated with daily number of depression admissions both on warm and cool days. In our two-pollutant models, O₃ levels remained significant after adjusting for other air pollutants, including particulate matter (PM₁₀, PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO) both on warm and cool days. Although O₃ levels tended to be higher on warm days, admissions for depression were higher on cool days, suggesting that the relationship between O₃ concentrations and depression may be affected by temperature. Further study is needed to better understand these findings.

Does ambient ozone air pollution trigger suicide attempts? A case cross-over analysis in Taipei

Epidemiologic studies indicated that exposure to ambient air pollutants was associated with increased mortality rates attributed to suicide. The objective of this study was to investigate the potential relationship between ambient ozone (O₃) levels and daily number of hospital admissions for suicide attempts in Taipei for the period 2008-2012 using a time-stratified case-crossover analysis. In the single-pollutant model (without adjustment for other pollutants), the risk of committing a suicide attempt increased by 9% on warm days and 27% on cool days for each interquartile range (IQR) rise in O₃ levels, respectively. The concentration of O₃ was thus significantly associated with daily number of suicide attempts both on warm and cool days. In the two-pollutant models, O₃ levels remained significant after the inclusion of other air pollutants (particulate matter (PM₁₀), PM_2.5, sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO)) on cool days. However, on warm days, no significant correlation was found between O₃ levels and reported daily number of suicide attempts. The relationship between O₃ and suicide attempts appeared to be dependent upon temperature; however, the basis for these observations requires further investigation.

Relationship between ozone air pollution and daily suicide mortality: a time-stratified case-crossover study in Taipei

Several studies suggested short-term exposure to air pollution might be associated with suicide mortality, although results have been inconsistent and vary depending upon the type of air contaminants. While seasonal variation associated with suicide was reported to occur and that in the spring and early summer there are peaks in ozone (O₃) distribution, the relationship between these two parameters is not known. The aim of this study was to examine the potential association between O₃ levels and daily mortality rate related to suicide in Taipei for the period 2004-2008 using a time-stratified case-crossover analysis. In our single pollutant model without adjustment for other pollutants, the risk of suicide increased by 11% on warm days and 15% on cool days for each interquartile range (IQR) rise in O₃ concentration, respectively. The relationship was positive but did not reach significance. In our two-pollutant models, O₃ remained non-significant on warm days after inclusion of one of any other ambient air contaminants into the model. However, on cool days, a significant association was found between O₃ levels and enhanced risk of mortality due to suicide after nitrogen dioxide (NO₂) or carbon monoxide (CO) were included. The overall positive but not significant findings of elevated risk of mortality frequently attributed to suicide on days with higher O₃ levels suggest that outdoor exposures to this gaseous contaminant may contribute to increases in daily mortality rate related to suicide.

Interactive effects of changing stratospheric ozone and climate on tropospheric composition and air quality, and the consequences for human and ecosystem health

The composition of the air we breathe is determined by emissions, weather, and photochemical transformations induced by solar UV radiation. Photochemical reactions of many emitted chemical compounds can generate important (secondary) pollutants including ground-level ozone (O₃) and some particulate matter, known to be detrimental to human health and ecosystems. Poor air quality is the major environmental cause of premature deaths globally, and even a small decrease in air quality can translate into a large increase in the number of deaths. In many regions of the globe, changes in emissions of pollutants have caused significant changes in air quality. Short-term variability in the weather as well as long-term climatic trends can affect ground-level pollution through several mechanisms. These include large-scale changes in the transport of O₃ from the stratosphere to the troposphere, winds, clouds, and patterns of precipitation. Long-term trends in UV radiation, particularly related to the depletion and recovery of stratospheric ozone, are also expected to result in changes in air quality as well as the self-cleaning capacity of the global atmosphere. The increased use of substitutes for ozone-depleting substances, in response to the Montreal Protocol, does not currently pose a significant risk to the environment. This includes both the direct emissions of substitutes during use and their atmospheric degradation products (e.g. trifluoroacetic acid, TFA).

Airway and systemic inflammatory responses to ultrafine carbon black particles and ozone in older healthy subjects

Increased adverse health effects in older subjects due to exposure to ambient air pollutants may be related to the inflammatory response induced by these contaminants. The aim of this study was to assess airway and systemic inflammatory responses in older healthy subjects to a controlled experimental exposure with spark-generated elemental carbon black ultrafine particles (cbUFPs) and ozone (O₃). Twenty healthy subjects, age 52-75 years, were exposed on three occasions separated by at least 8 weeks. The exposures to filtered air (FA), to cbUFP (50 μg/m³), or to cbUFP in combination with 250 ppb ozone (cbUFP + O₃) for 3 h with intermittent exercise were performed double blind, and in random order. Sputum and blood samples were collected 3.5 h after each exposure. Exposure to cbUFP + O₃ significantly increased plasma club cell protein 16 (CC16), the number of sputum cells, the number and percent of sputum neutrophils, and sputum interleukin 6 and matrix metalloproteinase 9. Exposure to cbUFP alone exerted no marked effect, except for an elevation in sputum neutrophils in a subgroup of 13 subjects that displayed less than 65% sputum neutrophils after FA exposure. None of the inflammatory markers was correlated with age, and serum cardiovascular risk markers were not markedly affected by cbUFP or cbUFP + O₃. Exposure to cbUFP+O₃ induced a significant airway and systemic inflammatory response in older healthy volunteer subjects. The effects induced by cbUFP alone suggest that the inflammation was predominantly mediated by O₃, although one cannot rule out that the interaction of cbUFP and O₃ played a role.

Association between fine particulate air pollution and hospital admissions for chest pain in a subtropical city: Taipei, Taiwan

This study determined the association between fine particles (PM_2.5) levels and hospital admissions for chest pain (CP) in Taipei, Taiwan. Hospital admissions for CP and ambient air pollution data for Taipei were obtained for the period 2009-2013. The relative risk of hospital admissions was estimated using a case-crossover approach, after controlling for weather variables, day of the week, seasonality, and long-term time trends. For single-pollutant models (without adjustment for other pollutants), increased frequency of CP admissions was significantly associated with PM_2.5 levels on warm days (>23°C), with an interquartile range rise correlated with a 15% (95% confidence interval = 11-31%) elevation in number of CP admissions. In two-pollutant models, PM_2.5 remained significant after inclusion of each of the other four pollutants: sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃) on warm days. Generally, no marked associations were observed between PM_2.5 levels and risk of CP admissions on cool days in both single- and two-pollutant models. This study provides evidence that higher PM_2.5 concentrations enhance the risk of hospital admissions for CP on warm days.