Spatio-seasonal variation in ambient air pollutants and influence of meteorological factors in Coimbatore,Southern India

Air quality is used worldwide to confirm the current status of air pollution level and associated health risks to the public. Several air pollutants reach very high concentrations in many regions across India. In this study, air pollutants were measured in an urban city of Coimbatore, Tamil Nadu, Southern India, during 2013 to 2014 based on season and location, and the influence of meteorological factors. Air pollutants (PM₁₀, PM_2.5, SO₂, NO₂, CO, and O₃) across eight locations including industrial, residential, traffic, and commercial areas were assessed. The results showed that PM₁₀, PM_2.5, and CO were the most serious pollutants and their average concentrations ranged from 65.5 to 98.6 μg/m³, 27.6 to 56.9 μg/m³, and 1.58 to 8.21 mg/m³, respectively, among various locations. Significantly higher concentration of air pollutants was recorded in industrial areas followed by traffic and commercial areas. Comparatively higher mean concentration of O₃ (2.22?±?0.75 μg/m³) and CO (7.73?±?1.86 mg/m³) was recorded during the summer season, whereas the concentration of PM₁₀ (80.3?±?24.4 μg/m³), PM_2.5 (45.1?±?17.7 μg/m³), SO₂ (7.86?±?1.55 μg/m³), and NO₂ (13?±?1.81 μg/m³) was higher in southwest monsoon. Ozone (O₃) and CO positively correlated with temperature and negatively correlated with relative humidity. The level of PM₁₀, PM_2.5, and CO concentrations exceeded the National Ambient Air Quality Standards (NAAQS) guidelines. The present study’s results emphasize the need of effective air pollution control in Coimbatore. Precautionary measures to be taken to avoid exposure of air pollutants to the public and minimize pollutants. This study further suggests an investigation on the adverse impact on human health and environment using appropriate risk analysis techniques.     

Spatial and temporal variations in criteria air pollutants in three typical terrain regions in Shaanxi,China, during 2015

Numerous studies have investigated air pollution in severely polluted plains, but the characteristics of pollutants are not well understood in other terrain regions. In this study, air pollution characteristics were analyzed in three typical terrain regions (plateau, plain, and mountain regions) in Shaanxi, based on hourly ambient monitoring of particulate matter with diameter less than 2.5 μm (PM_2.5) and less than 10 μm (PM₁₀), CO, SO₂, NO₂, and O₃ in 2015. PM_2.5 and PM₁₀ were the dominant pollutants in three regions, and their annual concentrations exceeded the Grade II standards by 9.4–68.6 and 6.0–73.9%, respectively. PM_2.5, PM₁₀, CO, SO₂, and NO₂ concentrations had similar seasonal trends with highest values in winter and lowest values in summer, whereas O₃ concentrations exhibited the opposite trend. Guanzhong Plain had higher PM_2.5, PM₁₀, NO₂, and SO₂ concentrations but lower CO, 1-h peak O₃, and 8-h peak O₃ (8 h-O₃) compared to other regions. PM_2.5, PM₁₀, and 8 h-O₃ were the three main dominant pollutants. The nonattainment rate was highest in winter and lowest in summer or autumn. Pollution also exhibited synergy, especially in the plateau region and Guanzhong Plain. PM_2.5 was significantly correlated with PM₁₀. NO₂ and SO₂ were positively correlated with PM_2.5 and PM₁₀, while 8 h-O₃ generally had significant negative correlations with other pollutants, especially in the winter. These results provide a comprehensive understanding of pollution status in the three typical terrain regions in Shaanxi and are helpful for improving air quality.     

Diurnal variations of ground-level ozone in three port cities in Malaysia

The diurnal variations of ground-level ozone (O₃) concentrations along a gradient of three major port cities (Klang, Perai, and Pasir Gudang) in Malaysia were evaluated. Annual monitoring records (2009) of O₃, nitrogen dioxide (NO₂), nitric oxide (NO), carbon monoxide (CO), sulfur dioxide (SO₂), and particulate matter (PM₁₀) were obtained. Weather-influencing parameters such as incoming solar radiation, temperature, relative humidity, and wind speed were also analyzed. Although an overwhelming majority (99.9 %) of the recorded data are below the prescribed levels in the Malaysian Ambient Air Quality Guidelines (MAAQG), a number of exceedances (0.1 %) (>100 ppb) have been recorded in Klang and Pasir Gudang. The annual hourly average concentrations of O₃ were 20.3?±?18.2, 15.4?±?15.8, and 14.4?±?13.1 ppb for Klang, Perai, and Pasir Gudang, respectively. The diurnal cycles of ground-level O₃ concentrations and cluster analysis suggest that a unimodal peak occurs between 1 p.m. and 3 p.m., and the highest O₃ concentrations were observed during the first quarter of 2009 as a result of the higher rate of local photochemical production. Results of principal component analysis showed that the contributions to O₃ level variation by meteorological variables (UVB, temperature, relative humidity, and wind speed) are higher at 47.7, 39.5, and 18.2 % than those of primary air pollutants (NO_x, CO, SO₂, PM₁₀) at 28.9, 32.6, and 45 % for Perai, Pasir Gudang, and Klang, respectively. The exposure of the population in the three port cities to the elevated levels of ozone during January–May months validated the increasing threat and risks that ozone presents to humans. Result indicated that the concentration of O₃ in the three ports was still below the maximum permissible values prescribed by the MAAQG, and expansion in shipping industries is possible in exaggerating O₃ problems especially in Klang.     

Characteristics of atmospheric trace gases, particulate matter, and heavy metal pollution in Dhaka, Bangladesh

Aerosol particulate matter (PM₁₀ and PM_2.5) and trace gases (SO₂, NO₂, CO and O₃) were sampled at five locations in greater Dhaka, Bangladesh, between January and April 2006. Particulate matter was collected on micro-fiber filters with a low-volume sampler, and trace gases (SO₂, NO₂, and O₃) were collected with an impinger equipped with PM samplers. Carbon monoxide was determined using the Indicator Tube method. The total average concentrations of SO₂, NO₂, CO, and O₃ were 48.3, 21.0, 166.0 and 28 μg m^–3, respectively. The total average concentrations of SO₂ and NO₂ were much lower than the annual average guideline values of the World Health Organization (WHO). The total average O₃ concentration was also much lower than the daily maximum values established by WHO (average of 100 μg m^–3 for an 8-h sample). The total average concentrations of five sites were 263, 75.5 and 66.2 μg m^–3 for SPM, PM₁₀ and PM_2.5, respectively. The mass of PM_2.5 is approximately 88% of the PM₁₀ mass, indicating that fossil fuel is the main source of PM in Dhaka. An atomic absorption spectrophotometer was used to determine the heavy metal concentrations in the PM_2.5 size fraction. The total average concentrations of As, Cd, Cu, Fe, Pb, and Zn in PM_2.5 were 6.3, 13, 94, 433, 204, and 381 ng m^–3, respectively. The Pb concentration in Dhaka shows a decreasing tendency, presumably due to the ban on the use of leaded fuel. The overall trace metal concentrations in Dhaka are higher than those in European (e.g., Spain, Norway) and East Asian (e.g., Taiwan) locations, but lower than those measured in Southeast Asian (Kanpur, Delhi, Mumbai, India; Lahore, Pakistan) cities.     

Trend and status of air quality at three different monitoring stations in the Klang Valley,Malaysia

Over the last decades, the development of the Klang Valley (Malaysia), as an urban commercial and industrial area, has elevated the risk of atmospheric pollutions. There are several significant sources of air pollutants which vary depending on the background of the location they originate from. The aim of this study is to determine the trend and status of air quality and their correlation with the meteorological factors at different air quality monitoring stations in the Klang Valley. The data of five major air pollutants (PM₁₀, CO, SO₂, O₃, NO₂) were recorded at the Alam Sekitar Sdn Bhd (ASMA) monitoring stations in the Klang Valley, namely Petaling Jaya (S1), Shah Alam (S2) and Gombak (S3). The data from these three stations were compared with the data recorded at Jerantut, Pahang (B), a background station established by the Malaysian Department of Environment. Results show that the concentrations of CO, NO₂ and SO₂ are higher at Petaling Jaya (S1) which is due to influence of heavy traffic. The concentrations of PM₁₀ and O_3, however, are predominantly related to regional tropical factors, such as the influence of biomass burning and of ultra violet radiation from sunlight. They can, though, also be influenced by local sources. There are relatively stronger inter-pollutant correlations at the stations of Gombak and Shah Alam, and the results also suggest that heavy traffic flow induces high concentrations of PM₁₀, CO, NO₂ and SO₂ at the three sampling stations. Additionally, meteorological factors, particularly the ambient temperature and wind speed, may influence the concentration of PM₁₀ in the atmosphere.     

Characteristics and Sources of Water-Soluble Ionic Species Associated with PM10 Particles in the Ambient Air of Central India

PM₁₀ aerosol samples were collected in Durg City, India from July 2009 to June 2010 using an Andersen aerosol sampler and analyzed for eight water-soluble ionic species, namely, Na⁺, NH₄ ⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃ ⁻ and SO₄ ²⁻ by ion chromatography. The annual average concentration of PM₁₀ (253.5 ± 99.4 μg/m³) was four times higher than the Indian National Ambient Air Quality Standard of 60 μg/m³ prescribed by the Central Pollution Control Board, India. The three most abundant ions were SO₄ ²⁻, NO₃ ⁻, and NH₄ ⁺, with average concentrations of 8.88 ± 4.81, 5.63 ± 2.22, and 5.18 ± 1.76 μg/m³, respectively, and in turn accounting for 27.1 %, 16.5 %, and 15.5 % of the total water-soluble ions analyzed. Seasonal variation was similar for all secondary ions i.e., SO₄ ²⁻, NO₃ ⁻, and NH₄ ⁺, with high concentrations during winter and low concentrations during monsoon. Varimax Rotated Component Matrix principal component analysis identified secondary aerosols, crustal resuspension, and coal and biomass burning as common sources of PM₁₀ in Durg City, India.     

Spatial and seasonal variations of gaseous and particulate matter pollutants in 31 provincial capital cities,China

In order to know air pollution situation and their health, environmental, and climate effects, the air quality data with high temporal and spatial resolutions are essential. The spatial and seasonal variations of six criteria pollutants were investigated in 31 provincial capital cities between April 2014 and March 2015 using hourly mean air quality monitoring data, and the cities were classified by cluster analysis based on annual variations of air pollutants. The annual mean concentrations of PM_2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) and PM₁₀ (particulate matter with aerodynamic diameter less than 10 μm) were high for all cities, which exceeded Chinese Ambient Air Quality Standards (CAAQS) Grade I standards. Only Fuzhou, Haikou, Kunming, and Lasa met Grade II standards for PM_2.5 and PM₁₀. Additionally, elevated SO₂ concentration was observed in northern cities, especially in winter. However, the seasonal variation of O₃ was opposite to other pollutants with the lowest concentrations in the winter and the highest in the summer. Winter domestic heating has significant impact on urban air quality, especially SO₂ and PM₁₀.     

Respiratory health effects among schoolchildren and their relationship to air pollutants in Korea

The objective of this study is to investigate the relationship between five air pollutants (PM₁₀, SO₂, NO₂, O₃, CO) measured on the daily basis, and adverse health symptoms using epidemiological surveillance data. The generalized estimated equation (GEE) model, a logistic regression analysis model, was used to estimate the effects of air pollution on children's daily health symptoms, focusing on the morbidity including both respiratory and allergic symptoms in four different cities. Analysis of the effects of each pollutant on children's respiratory and allergic symptoms demonstrated that CO affected all symptoms in all the study areas. When the concentration of SO₂ and NO₂ was elevated, upper respiratory symptoms increased significantly. In contrast, when the concentration of O₃ rose, the symptoms decreased significantly. The relationship between measured concentrations and health symptoms was site-dependent for each pollutant.     

Ambient air pollution and lipoprotein-associated phospholipase A₂ in survivors of myocardial infarction

Background: Increasing evidence suggests a proatherogenic role for lipoprotein-associated phospholipase A₂ (Lp-PLA2). A meta-analysis of published cohorts has shown that Lp-PLA2 is an independent predictor of coronary heart disease events and stroke.Objective: In this study, we investigated whether the association between air pollution and cardiovascular disease might be partly explained by increased Lp-PLA2 mass in response to exposure.Methods: A prospective longitudinal study of 200 patients who had had a myocardial infarction was performed in Augsburg, Germany. Up to six repeated clinical examinations were scheduled every 4–6 weeks between May 2003 and March 2004. Supplementary to the multicenter AIRGENE protocol, we assessed repeated plasma Lp-PLA2 concentrations. Air pollution data from a fixed monitoring site representing urban background concentrations were collected. We measured hourly means of particle mass [particulate matter (PM) < 10 µm (PM₁₀) and PM < 2.5 µm (PM_2.5) in aerodynamic diameter] and particle number concentrations (PNCs), as well as the gaseous air pollutants carbon monoxide (CO), sulfur dioxide (SO₂), ozone (O₃), nitric oxide (NO), and nitrogen dioxide (NO₂). Data were analyzed using mixed models with random patient effects.Results: Lp-PLA2 showed a positive association with PM₁₀, PM_2.5, and PNCs, as well as with CO, NO₂, NO, and SO₂ 4–5 days before blood withdrawal (lag 4–5). A positive association with O₃ was much more immediate (lag 0). However, inverse associations with some pollutants were evident at shorter time lags.Conclusion: These preliminary findings should be replicated in other study populations because they suggest that the accumulation of acute and subacute effects or the chronic exposure to ambient particulate and gaseous air pollution may result in the promotion of atherosclerosis, mediated, at least in part, by increased levels of Lp-PLA2.     

Seasonal Air Quality Profile of Size-Segregated Aerosols in the Ambient Air of a Central Indian Region

Seasonal distribution trends of size-segregated aerosols i.e. submicron (PM₁), fine (PM_2.5) and coarse (PM_2.5–10) and their relationship with meteorological variables employing correlation analysis were studied in the ambient air of central India from July 2009 to June 2010. The annual mean concentrations of PM₁, PM_2.5 and PM_2.5–10 were found to be 65.7, 135.0 and 118.5 μg m^?3, respectively. The annual mean PM_2.5 concentration is three times higher than the National Ambient Air Quality Standards of India (NAAQS). Higher concentrations of PM₁, PM_2.5 and PM_2.5–10 were found during winter due to enormous biomass burning especially during night time due to the use of combustible goods like fire wood and dung cake in the open space by the peoples to keep themselves warm and lower concentrations were observed during monsoon when there were high precipitations. PM_2.5 showed high positive correlation with PM₁ (r = 0.69) and moderate correlation with PM_2.5–10 indicating that variation in PM_2.5 mass is governed by the variation in PM₁ mass or vice versa.     

Daily Mortality and PM10 Pollution in Utah Valley

The association between daily mortality and respirable particulate pollution (PM₁₀) in Utah County was assessed from April 1985 through December 1989. Poisson regression analysis was used to regress daily death counts on PM₁₀ pollution levels, controlling for variability in the weather. A significant positive association between nonaccidental mortality and PM₁₀ pollution was observed. The strongest association was with 5-d moving average PM₁₀ levels, including the concurrent day and the preceding 4 d. An increase in 5-d moving average PM₁₀ levels, equal to 100 μg/m², was associated with an estimated increase in deaths per day equal to 16%. The association with mortality and PM₁₀ was largest for respiratory disease deaths, next largest for cardiovascular deaths, and smallest for all other deaths. Mean PM₁₀ concentrations during the study period equaled 47 μg/m². The maximum 24-h and 5-d moving average PM₁₀ levels equaled 365 and 297 μg/m³, respectively. Relatively low levels of sulfur dioxide, aerosol acidity, and ozone suggested an independent association between mortality and PM₁₀. The relative risk of death increased monotonically with PM₁₀, and the relationship was observed at PM₁₀ levels that were well below the current National Ambient Air Quality Standard of 150 μg/m³.     

Residential greenness and kidney function: A cohort study of Thai employees

Higher residential greenness is associated with a lower risk of chronic kidney disease, but evidence on the association between greenness exposure and kidney function has not been conducted. Using cohort data from Electricity Generating Authority of Thailand (EGAT) employees, we investigated the association between long-term exposure to greenness and kidney function using estimated glomerular filtration rate (eGFR) in Bangkok Metropolitan Region (BMR), Thailand. We analyzed data from 2022 EGAT workers (aged 25–55 years at baseline) from 2009 to 2019. The level of greenness was calculated using the satellite-derived Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI). From 2008 to 2019, the average concentration of each air pollutant (PM₁₀, O₃, NO₂, SO₂, and CO) at the sub-district level in BMR was generated using the Kriging method. Long-term exposure for each participant was defined as the 1-year average concentrations before the date of the physical examination in 2009, 2014, and 2019. We employed linear mixed effects models to evaluate associations of NDVI and EVI with eGFR. The robustness of the results was also tested by including air pollutants in the models. After relevant confounders were controlled, the interquartile range increase in NDVI was associated with higher eGFR [1.03% (95%CI: 0.33, 1.74)]. After PM₁₀ and SO₂ were included in the models, the associations between NDVI and eGFR became weaker. The additions of O₃, NO₂, and CO strengthened the associations between them. In contrast, we did not find any association between EVI and eGFR. In conclusion, there was a positive association between NDVI and eGFR, but not for EVI. Air pollutants had a significant impact on the relationship between NDVI and eGFR. Additional research is needed to duplicate this result in various settings and populations to confirm our findings.     

Trends and patterns of air quality in Santa Cruz de Tenerife (Canary Islands) in the period 2011–2015

Air quality trends and patterns in the coastal city of Santa Cruz de Tenerife (Canary Islands, Spain) for the period 2011–2015 were analyzed. The orographic and meteorological characteristics, the proximity to the African continent, and the influence of the Azores anticyclone in combination with the anthropogenic (oil refinery, road/maritime traffic) and natural emissions create specific dispersion conditions. SO₂, NO₂, PM₁₀, PM_2.5, and O₃ pollutants were assessed. The refinery was the primary source of SO₂; EU hourly and daily average limit values were exceeded during 2011 and alert thresholds were reached in 2011 and 2012. WHO daily mean guideline was occasionally exceeded. Annual averages in the three stations that registered the highest concentrations in 2011 and 2012 were between 9.3 and 20.4 μg/m³. The spatial analysis of SO₂ concentrations with respect to prevailing winds corroborates a clear influence of the refinery to the SO₂ levels. In 2014 and 2015, the refinery did not operate and the concentrations fell abruptly to background levels of 2.5–7.1 μg/m³ far below from WHO AQG. NO₂ EU limit values, as well as WHO AQG for the period 2011–2015, were not exceeded. The progressive dieselization of the vehicle fleet caused an increment on NO₂ annual mean concentrations (from 2011 to 2015) measured at two stations close to busy roads 25 to 31 μg/m³ (+21%) and 27 to 35 μg/m³ (+29%). NO _x daily and weekly cycles (working days and weekends) were characterized. An anti-correlation was found between NO _x and O₃, showing that O₃ is titrated by locally emitted NO. Higher O₃ concentrations were reported because less NO _x emitted during the weekends showing a clear weekend effect. Saharan dust intrusions have a significant impact on PM levels. After subtracting natural sources contribution, none of the stations reached the EU maximum 35 yearly exceedances of daily means despite seldom exceedances at some stations. None of the stations exceeded the annual mean EU limit values; however, many stations exceeded the annual mean WHO AQG. Observed PM₁₀ annual average concentrations in all the stations fluctuated between 10.1 and 35.3 μg/m³, where background concentrations were 6.5–24.4 μg/m³ and natural contributions: 4.2–9.1 μg/m³. No PM₁₀ temporal trends were identified during the period except for an effect of washout due to the rain: concentrations were lower in 2013 and 2014 (the most rainy years of the period). None of the stations reached the PM_2.5 annual mean EU 2015 limit value. However, almost all the stations registered daily mean WHO AQG exceedances. During 2015, PM_2.5 concentrations were higher than the previous years (2015, 8.8–12.3 μg/m³; 2011–2014, 3.7–9.6 μg/m³). O₃ complied with EU target values; stricter WHO AQG were sometimes exceeded in all the stations for the whole time period.     

Exploratory study of air quality in elementary schools,Coimbra, Portugal

OBJECTIVE

To analyze the air quality in elementary schools and their structural and functional conditions.

METHODS

Air quality in 51 elementary schools (81 classrooms) in the city of Coimbra, Portugal, both inside and outside of the rooms was evaluated during the four seasons, from 2010 to 2011. Temperature (T°), relative humidity (Hr), concentrations of carbon monoxide (CO), carbon dioxide (CO₂), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), compounds were evaluated, as were volatile organics (VOC), formaldehyde and particulate matter (PM₁₀), from November 2010 to February 2011 (autumn/winter) and March 2011 to June 2011 (spring/summer). A grid characterizing the structural and functional conditions of the schools was created. The statistical Student t test for paired samples and the Wilcoxon t test were applied.

RESULTS

In 47 schools, the average CO₂concentrations were above the maximum reference concentration (984 ppm) mentioned in Portuguese legislation. The maximum concentration values found inside the rooms were critical, especially in the fall/winter (5,320 ppm). In some schools the average concentrations of VOC and PM₁₀within the maximum concentration exceeded the reference legislated. The values (risk) of CO, formaldehyde, NO₂, SO₂and O₃detected were not relevant.

CONCLUSIONS

There was a higher concentration of pollutants inside the rooms compared with outside. Inadequate ventilation is associated with high CO₂concentration in the classroom.     

Air pollution and admissions for acute lower respiratory infections in young children of Ho Chi Minh City

This study assessed the effects of exposure to air pollution on hospitalization for acute lower respiratory infection (ALRI) among children under 5 years of age in Ho Chi Minh City (HCMC) from 2003 to 2005. Case-crossover analyses with time-stratified selection of control periods were conducted using daily admissions for pneumonia and bronchiolitis and daily, citywide averages of PM₁₀, NO₂, SO₂, and O₃ (8-h maximum average) estimated from the local air quality monitoring network. Increased concentrations of NO₂ and SO₂ were associated with increased admissions in the dry season (November to April), with excess risks of 8.50% (95%CI 0.80–16.79) and 5.85% (95%CI 0.44–11.55), respectively. PM₁₀ could also be associated with increased admissions in the dry season, but high correlation between PM₁₀ and NO₂ (0.78) limits our ability to distinguish between PM₁₀ and NO₂ effects. In the rainy season (May–October), negative associations between pollutants and admissions were observed. Results of this first study of the health effects of air pollution in HCMC support the presence of an association between combustion-source pollution and increased ALRI admissions. ALRI admissions were generally positively associated with ambient levels of PM₁₀, NO₂, and SO₂ during the dry season, but not the rainy season. Negative results in the rainy season could be driven by residual confounding present from May to October. Preliminary exploratory analyses suggested that seasonal differences in the prevalence of viral causes of ALRI could be driving the observed differences in effects by season.     

Ambient air pollution and emergency department visits among children and adults in Casablanca,Morocco

This study presents the relationships between ambient air pollutants and morbidity and emergency department visits among children and adults performed in Great Casablanca, the most populated and economic region in Morocco. This research was analyzed using conditional Poisson model for the period 2011–2013. In the period of study, the daily average concentrations of SO₂, NO₂, O₃ and PM₁₀ in Casablanca were 209.4 µg/m³, 61 µg/m³, 113.2 µg/m³ and 75.1 µg/m³, respectively. In children less than 5 years old, risk of asthma could be increased until 12% per 10 µg/m³ increase in NO₂, PM10, SO₂ and O₃. In children over 5 years and adults, an increase of 10 µg/m³ air pollutant can cause an increase until 3% and 4% in respiratory consultations and acute respiratory infection, respectively. Similarly, impact on emergency department visits due to respiratory and cardiac illness was established. Our results suggest a not negligible impact on morbidity of outdoor air pollution by NO₂, SO₂, O₃, and PM₁₀.     

Ozone and other air pollutants and the risk of oral clefts

Background

Air pollution influences the development of oral clefts in animals. There are few epidemiologic data on the relation of prenatal air pollution exposure and the risk of oral clefts.

Objectives

Our goal in this study was to assess the relations between exposure to ambient air pollution and the risk of cleft lip with or without cleft palate (CL/P).

Methods

We conducted a population-based case–control study of all 653 cases of CL/P and a random sample of 6,530 control subjects from 721,289 Taiwanese newborns in 2001–2003. We used geographic information systems to form exposure parameters for sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, and particulate matter with an aerodynamic diameter ≤ 10 μm (PM₁₀) during the first 3 months of pregnancy using inverse distance weighting method. We present the effect estimates as odds ratios (ORs) per 10-ppb change for SO₂, NO_x, and O₃, 100-ppb change for CO, and 10-μg/m³ change for PM₁₀.

Results

The risk of CL/P was increased in relation to O₃ levels in the first gestational month [adjusted OR = 1.20; 95% confidence interval (CI), 1.02–1.39] and second gestational month (adjusted OR = 1.25; 95% CI, 1.03–1.52) in the range from 16.7 ppb to 45.1 ppb, but was not related to CO, NO_x, SO₂, or PM₁₀.

Conclusions

The study provides new evidence that exposure to outdoor air O₃ during the first and second month of pregnancy may increase the risk of CL/P. Similar levels of O₃ are encountered globally by large numbers of pregnant women.     

Roadside atmospheric pollution: still a serious environmental problem in Beijing,China

China has made great efforts to reduce ambient atmospheric pollutant concentrations in the past few decades. The air quality in northern China has improved greatly. However, most research has focused on atmospheric pollution in non-roadside environments that have little influence from traffic flow and are impacted by less vehicle exhaust. In this study, hourly air quality monitoring data were collected at four traffic stations and four nontraffic stations in Beijing from June 2014 to September 2017 to analyze the spatial-temporal variations of atmospheric pollutants related to traffic. The traffic stations had higher concentrations of PM_2.5, PM₁₀, SO₂, NO₂, and CO but lower concentrations of O₃. Although the overall air quality in Beijing is improving, the pollution rates of PM_2.5, PM₁₀, and NO₂ in the traffic stations were still high at 47.91%, 50.71%, and 61.22% concentrations, respectively. The air pollution levels in traffic environments are systematically higher than those in nontraffic environments, during both daytime and nighttime, except O₃. Furthermore, the traffic stations near ring roads with large numbers of diesel trucks were even more polluted, suggesting the influence of traffic emissions. Under adverse meteorological dispersion conditions, both the traffic and nontraffic stations had high pollution levels, but the pollution at the traffic stations was much higher. To reduce the air pollution level, a series of vehicle restriction rules have been imposed, including license plate restriction. Our analysis revealed obvious cycles associated with license plate restriction rules, suggesting the possibility for further improvement in vehicle restriction rules. The results from our study suggest that roadside environments with heavy traffic in Beijing, China, are still highly polluted and need further efforts to improve.     

中国空气污染与不良出生结局的研究进展

目的 对中国空气污染与不良出生结局的相关研究进展进行综述。方法 通过检索万方、中国知网（CNKI）、PubMed、Science Direct、Web of Science等数据库2016年6月30日前发表的中国人群空气污染物暴露与不良出生结局相关文献,按照制定的纳入排除标准进行筛选,并对纳入的27篇文献进行综述。结果 中国孕产妇妊娠期间空气动力学直径≤10 μm的颗粒物（PM₁₀）、二氧化硫（SO₂）、二氧化氮（NO₂）、总悬浮颗粒物（TSP）暴露可能增加低出生体重发病风险;妊娠期间暴露PM₁₀、SO₂、NO₂可能增加早产发病风险;妊娠期间暴露SO₂、NO₂、臭氧（O₃）、PM₁₀可能增加先天性心脏缺陷及其他出生缺陷发病风险。结论 中国孕产妇妊娠期间空气污染物暴露可能增加不良出生结局发病风险,需进一步开展研究探讨其相关性。     

Association between daily mortality from respiratory and cardiovascular diseases and air pollution in Taiwan

Background

Many studies have investigated the effects of air pollutants on disease and mortality. However, the results remain inconsistent and inconclusive. We thought that the impact of different seasons or ages of people may explain these differences.

Methods

Measurement of the five pollutants (particulate matter <10 μm in aerodynamic diameter (PM₁₀), SO₂, NO₂, O₃, and CO) was monitored by automated measuring units at five different stations. Monitoring stations were provided by the Taiwan Environmental Protection Agency (EPA) from 1997 to 1999. The subjects in the study were classified in two groups: those 65 years of age and older, and those of all ages (including the subjects in the ?65 group). Data on daily mortality caused by respiratory disease, cardiovascular disease, and all other causes including the two aforementioned was collected by the Taiwan Department of Health (DOH). A time-series regression model was used to analyze the relative risk of respiratory and cardiovascular diseases due to air pollution in the summer and winter seasons.

Results

Risk of death from all causes and mortality from cardiovascular diseases during winter was significantly positively correlated with levels of SO₂, CO, and NO₂ for both groups of subjects and additionally with PM₁₀ for the elderly (?65 years old) group. There were significant positive correlations with respiratory diseases and levels of O₃ for both groups. However, the only significant positive correlation was with O₃ (RR=1.283) for the elderly group during summer. No other parameters showed significance for either group.

Conclusion

Our findings contribute to the evidence of an association between SO₂, CO, NO₂, and PM₁₀ and mortality from respiratory and cardiovascular diseases, especially among elderly people during the winter season.