BACKGROUND: Ambient air pollution, including particulate matter (such as PM10 and PM2·5) and nitrogen dioxide (NO2), has been linked to increases in mortality. Whether populations' vulnerability to these pollutants has changed over time is unclear, and studies on this topic do not include multicountry analysis. We evaluated whether changes in exposure to air pollutants were associated with changes in mortality effect estimates over time. METHODS: We extracted cause-specific mortality and air pollution data collected between 1995 and 2016 from the Multi-Country Multi-City (MCC) Collaborative Research Network database. We applied a two-stage approach to analyse the short-term effects of NO2, PM10, and PM2·5 on cause-specific mortality using city-specific time series regression analyses and multilevel random-effects meta-analysis. We assessed changes over time using a longitudinal meta-regression with time as a linear fixed term and explored potential sources of heterogeneity and two-pollutant models. FINDINGS: Over 21·6 million cardiovascular and 7·7 million respiratory deaths in 380 cities across 24 countries over the study period were included in the analysis. All three air pollutants showed decreasing concentrations over time. The pooled results suggested no significant temporal change in the effect estimates per unit exposure of PM10, PM2·5, or NO2 and mortality. However, the risk of cardiovascular mortality increased from 0·37% (95% CI -0·05 to 0·80) in 1998 to 0·85% (0·55 to 1·16) in 2012 with a 10 μg/m3 increase in PM2·5. Two-pollutant models generally showed similar results to single-pollutant models for PM fractions and indicated temporal differences for NO2. INTERPRETATION: Although air pollution levels decreased during the study period, the effect sizes per unit increase in air pollution concentration have not changed. This observation might be due to the composition, toxicity, and sources of air pollution, as well as other factors, such as socioeconomic determinants or changes in population distribution and susceptibility. FUNDING: None.

• MeSH
• kardiovaskulární nemoci * mortalita   MeSH
• látky znečišťující vzduch * škodlivé účinky   analýza   MeSH
• lidé MeSH
• nemoci dýchací soustavy * mortalita   chemicky indukované   MeSH
• oxid dusičitý * analýza   škodlivé účinky   MeSH
• pevné částice * analýza   škodlivé účinky   MeSH
• velkoměsta * MeSH
• vystavení vlivu životního prostředí škodlivé účinky   MeSH
• znečištění ovzduší * škodlivé účinky   analýza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• velkoměsta * MeSH
• Názvy látek
• látky znečišťující vzduch * MeSH
• oxid dusičitý * MeSH
• pevné částice * MeSH

BACKGROUND: The epidemiological evidence on the interaction between heat and ambient air pollution on mortality is still inconsistent. OBJECTIVES: To investigate the interaction between heat and ambient air pollution on daily mortality in a large dataset of 620 cities from 36 countries. METHODS: We used daily data on all-cause mortality, air temperature, particulate matter ≤ 10 μm (PM10), PM ≤ 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) from 620 cities in 36 countries in the period 1995-2020. We restricted the analysis to the six consecutive warmest months in each city. City-specific data were analysed with over-dispersed Poisson regression models, followed by a multilevel random-effects meta-analysis. The joint association between air temperature and air pollutants was modelled with product terms between non-linear functions for air temperature and linear functions for air pollutants. RESULTS: We analyzed 22,630,598 deaths. An increase in mean temperature from the 75th to the 99th percentile of city-specific distributions was associated with an average 8.9 % (95 % confidence interval: 7.1 %, 10.7 %) mortality increment, ranging between 5.3 % (3.8 %, 6.9 %) and 12.8 % (8.7 %, 17.0 %), when daily PM10 was equal to 10 or 90 μg/m3, respectively. Corresponding estimates when daily O3 concentrations were 40 or 160 μg/m3 were 2.9 % (1.1 %, 4.7 %) and 12.5 % (6.9 %, 18.5 %), respectively. Similarly, a 10 μg/m3 increment in PM10 was associated with a 0.54 % (0.10 %, 0.98 %) and 1.21 % (0.69 %, 1.72 %) increase in mortality when daily air temperature was set to the 1st and 99th city-specific percentiles, respectively. Corresponding mortality estimate for O3 across these temperature percentiles were 0.00 % (-0.44 %, 0.44 %) and 0.53 % (0.38 %, 0.68 %). Similar effect modification results, although slightly weaker, were found for PM2.5 and NO2. CONCLUSIONS: Suggestive evidence of effect modification between air temperature and air pollutants on mortality during the warm period was found in a global dataset of 620 cities.

• Klíčová slova
• Air pollution, Air temperature, Effect modification, Epidemiology, Mortality,
• MeSH
• látky znečišťující vzduch * škodlivé účinky   analýza   MeSH
• oxid dusičitý škodlivé účinky   analýza   MeSH
• pevné částice škodlivé účinky   analýza   MeSH
• velkoměsta MeSH
• vysoká teplota MeSH
• vystavení vlivu životního prostředí škodlivé účinky   analýza   MeSH
• znečištění ovzduší * škodlivé účinky   analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• metaanalýza MeSH
• Geografické názvy
• velkoměsta MeSH
• Názvy látek
• látky znečišťující vzduch * MeSH
• oxid dusičitý MeSH
• pevné částice MeSH

We report analysis of data on outdoor air pollution and respiratory symptoms in children collected in the Czech part of the international Small Area Variations in Air pollution and Health (SAVIAH) Project, a methodological study designed to test the use of geographical information systems (GIS) in studies of environmental exposures and health at small area level. We collected the following data in two districts of Prague: (1) individual data on 3,680 children (response rate 88%) by questionnaires; (2) census-based socio-demographic data for small geographical units; (3) concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) measured by passive samplers in three 2-week surveys at 80 and 50 locations, respectively. We integrated all data into a geographical information system. Modeling of NO2 and SO2 allowed estimation of exposure to outdoor NO2 and SO2 at school and at home for each child. We examined the associations between air pollution and prevalence of wheezing or whistling in the chest in the last 12 months by logistic regression at individual level, weighted least squares regression at small area (ecological) level and multilevel modeling. The results varied by the level of analysis and method of exposure estimation. In multilevel analyses using individual data, odds ratios per 10 microg/m3 increase in concentrations were 1.16 (95% CI = 0.95-1.42) for NO2, and 1.08 (95% CI = 0.97-1.21) for SO2. While mapping of spatial distribution of NO2 and SO2 in the study area appeared valid, the interpolation from outdoor to personal exposures requires consideration.

• MeSH
• dítě MeSH
• látky znečišťující vzduch škodlivé účinky   analýza   MeSH
• lidé MeSH
• lineární modely MeSH
• oxid dusičitý škodlivé účinky   analýza   MeSH
• oxid siřičitý škodlivé účinky   analýza   MeSH
• poruchy dýchání chemicky indukované   epidemiologie   MeSH
• prevalence MeSH
• průzkumy a dotazníky MeSH
• respirační zvuky * MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• látky znečišťující vzduch MeSH
• oxid dusičitý MeSH
• oxid siřičitý MeSH

The primary objective of the SAVIAH, a multi-centre study funded by European Union, was to assess new methodology for study of small area health statistics and to implement it in epidemiological health statistics and geography. In Prague, the study has been conducted in two city districts with large variation in air pollution. Data at individual level (health symptoms and socio-economic circumstances of the family) were collected by questionnaires completed by parents of 3680 children aged 7-10 both resident and attending schools within the area (response rate 88%). Aggregated data for geographical areas were available from census and urban planning sources for 692 enumeration districts in the study area which were aggregated into 75 medium sized areas. Outdoor concentrations of nitrogen dioxide (NO2) were monitored by passive samplers. All these data were integrated into a geographic information system (GIS). Spatial distribution of air pollution was estimated by kriging and multiple regression modelling. These models explained about 80% of the variation in air pollution measured by passive samplers. GIS was then used to assign to individuals an exposure based on place of residence and school in order to conduct individual based analyses. Association between NO2 and life-time prevalence of wheezing and/or whistling, and wheezing/whistling in the last 12 months was studied by logistic regression. For both outcomes, school levels of NO2 were positively related to symptoms but home levels of NO2 showed a negative association. Logistic regression at individual level gives similar results as ecological analysis and multilevel modelling. Hierarchical model yielded somewhat wider confidence limits. Adjustment for parental behavioural and socio-economic factors did not affect these estimates substantially. This study demonstrated the power of the GIS methodology in studying the effects of complex environmental factors on respiratory health of children.

• MeSH
• analýza malých oblastí * MeSH
• dítě MeSH
• informační systémy * MeSH
• lidé MeSH
• logistické modely MeSH
• metoda nejmenších čtverců MeSH
• nemoci dýchací soustavy epidemiologie   MeSH
• odds ratio MeSH
• oxid dusičitý škodlivé účinky   analýza   MeSH
• prevalence MeSH
• rizikové faktory MeSH
• socioekonomické faktory MeSH
• výfukové emise vozidel škodlivé účinky   MeSH
• znečištění ovzduší škodlivé účinky   analýza   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• oxid dusičitý MeSH
• výfukové emise vozidel MeSH

The light microscopical, histochemical and ultrastructural changes induced by NO2 were studied in lung tissue of experimental mice. The animals were daily exposed to NO2 for one hour and after 12 days we observed focal light microscopical changes (dilatation of alveolar crypts, minute inflammatory infiltrates). A rather high point activity of acid phosphatase was found, particularly in the cytoplasm of alveolar and septal macrophages. The light microscopical findings were supported by ultrastructural changes, i.e. vacuolation up to disintegration of alveolar pneumocytes, multiplication of macrophages, thickening of alveolar septa with multiplication of collagenous fibrils and infiltrate consisting of lymphocytes and plasma cells. The endothelium of capillaries displayed vacuolation and thickening of basal membrane in some sections. The quantitative examination showed multiplication of goblet cells in the epithelium of bronchial stroma of experimental animals compared to the controls. No morphological changes in the myocardium of the control group were observed even at ultrastructural level.

• MeSH
• látky znečišťující vzduch škodlivé účinky   MeSH
• myši MeSH
• oxid dusičitý škodlivé účinky   MeSH
• plíce účinky léků   patologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• látky znečišťující vzduch MeSH
• oxid dusičitý MeSH