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At least 505 records · Page 28Linked to original sources
PubMed2001

Life history and spatial distribution of the enchytraeid worm Cognettia sphagnetorum (Oligochaeta) in metal-polluted soil: below-ground sink-source population dynamics?

We studied the life history, metal-avoidance behavior, spatial distribution, and population growth of enchytraeid worms (Cognettia sphagnetorum [Oligochaeta]) originating from two sites: one uncontaminated, and another patchily polluted by heavy metals. Effects of patchy soil contamination on populations were studied in microcosms. In uncontaminated soil, worms from the polluted site had lower viability and reduced growth rate as juveniles but higher growth rate as adults compared to worms from the unpolluted site. They were also smaller in size at fragmentation (reproduction). Worms from the polluted site reached a larger population size than worms from the unpolluted site. Hence, worms from the polluted site seemed to allocate more energy to reproduction, because such a strategy can be highly adaptive when living in a less-polluted patch (the source) in, on average, a highly polluted environment. The C. sphagnetorum actively avoided Cu-contaminated soil, with the response being stronger in individuals from the contaminated site. When an unpolluted patch (the source) was surrounded by a toxic environment (the sink), worms were found in the sink, either because intraspecific competition overrode the avoidance behavior or because of random walk migration. As a result, total population size in these microcosms were as high as those in totally uncontaminated microcosms. Our results indicate that avoidance behavior and increased allocation to reproduction, together with the observed dispersal pattern, can be an adaptive strategy for C. sphagnetorum in the presence of small, less-polluted patches in, on average, a hostile environment. Hence, sink-source population regulation can explain spatial distribution and survival of C. sphagnetorum in patchily polluted field soils. When such population dynamics occur, this pattern should be taken into account when population densities in the field are monitored for ecological risk-assessment procedures concerning toxicants.

Adaptation, Physiological↗
PubMedDate not supplied

[The effect of sex factors on cytologic changes in the sputum of young adults exposed to urban air pollution].

UNLABELLED: The harmful effect of occupational and urban air pollution on the function and structure of the respiratory tract has been proved. The severity and incidence of epithelial changes are in direct relation to duration of exposure and age of the examined population groups [1]. Squamous metaplasia of bronchial epithelium is an indicator of predisposition to chronic obstructive pulmonary disease and lung cancer [1-5]. Due to its topography and the development of industry and traffic, Sarajevo used to be the city with an extremely high level of air pollution [10-12]. Some studies in adults showed that the respiratory tract exposed to air pollution responded with more severe changes in men than in women [7-9]. The aim of this study was to compare cytological changes in sputa, depending on the sex of young adults exposed to a high level of urban air pollution, and to examine whether a big difference in duration of exposure has an effect on these relations. MATERIALS AND METHODS: The subjects in the study were young adults, university students (21 to 25 years of age), all non-smokers. At the time of sputa collection (March-April 1991) they were clinically healthy with no history of chronic and serious acute respiratory diseases. They were divided into two groups according to the duration of air pollution exposure. The first group included those who had been living in Sarajevo since birth. The second group included those who used to live in pollution-free areas, but for the last two to three years had been living in Sarajevo where they came to attend the University (Table 1). Specimens were early morning spontaneously produced sputa, expectorated directly into Saccomanno's fixative and after centrifugation immersed in paraffin. Nine sections from each block were cut and stained with haematoxylin and eosin. The differences between cytological findings were tested with Hi2 test and Fisher's exact test, regarding sex and duration of exposure to air pollution. RESULTS: The findings are summarized in Table 1. As many as 63% and 64% of the subjects from the first and the second group, respectively, were able to produce sputum, while the others produced saliva only. All sputa contained abnormal bronchial columnar cells and half of them contained respiratory spirals (Figures 1 and 2). Squamous metaplastic cells were found in 7% and 9% of subjects in the first and second group, respectively. These cells showed no evidence of atypia. Statistical tests failed to identify significant differences in the incidence of cytological findings between the groups regarding both the sex of the subjects and duration of their exposure to air pollution (Table 2). DISCUSSION: The ability to produce sputum with the frequent presence of respiratory spirals in both groups of our subjects indicate an extremely harmful effect of smog. However, the incidence of squamous metaplastic cell findings was less severe comparing to adults and the elderly urban population. In the elderly (65 to 105 years of age) severe epithelial changes developed spontaneously in the absence of any other known aetiological factor [8, 9]. The increase in severity of changes in the course of aging, in our opinion, due to a gradual decline in efficiency of the defence mechanisms and regenerative potential of the respiratory system. The experimental study showed a decline of the efficiency of mucociliary clearance [14] as well as the damage of the function and decrease in number of alveolar macrophages in lung parenchyma and bronchoalveolar lavage [15, 16]. Trying to answer the question why the sex-related differences in the severity and incidence of epithelial changes appear in the groups of adults and the elderly, it is presumed that in aging the defence and regenerative potentials decline more rapidly in men than in women. (ABSTRACT TRUNCATED)

Adult↗
PubMedDate not supplied

[Air pollutants and their monitoring].

Some basic concepts regarding air pollution are set out. Although, from a health care standpoint, our interest revolves around the impact which pollution has on human health, it being important to ascertain the main pollutants, the sources of emissions, the physiochemical properties thereof, the sampling and analysis methods which are used at the air pollution control stations, the limits set by the laws currently in impact and the World Health Organization recommendations with regard to the levels of immission. This study reviews these concepts with regard to the pollutants which have been analyzed in the Spanish Multicenter Study of Air Pollution and Mortality (EMECAM): particles, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3). For this purpose, the most recent publications on this subject have been used, including part of what is going to be the line around which all of the measures aimed at combating air pollution are going to be revolving in the very near future, that is, the new set of European Union Directives (some currently in the proposal stage) and the latest recommendations (not as yet published) of the World Health Organization. Lastly, a wide range of aspects are set out which involve Public Health in the field of air pollution, despite the monitoring and control thereof falling to the environmental affairs authorities in terms of government organization.

Air Pollutants↗
PubMed2000

[Characteristics of cardiac and nervous system impairment in patients with systemic lupus erythematosus from regions with various levels of environmental pollution].

AIM: To characterize clinical features of systemic lupus erythematosus (SLE) in persons living under various environmental pollution. MATERIAL AND METHOD: Three groups of SLE patients living in the Orenburg region were examined: those exposed to intensive production pollution (n = 35 patients), exposed to mild pollution (n = 15), unexposed to production pollution (n = 25 patients). The pollution intensity was assessed by total aerogenic, water and soil pollution rates. RESULTS: The hair from 69 patients contained 24 chemical elements. More severe clinical symptoms of SLE were registered in patients living in conditions of intensive production pollution. These symptoms' severity directly correlated with the level of heavy metals in the hair of SLE patients and inversely correlated with hair levels of essential chemical elements. CONCLUSION: Chemical pollutants directly impair organs and tissues of SLE patients and indirectly do this via damaged immune system.

Adult↗
PubMed2002

Urban air pollution and respiratory allergy.

Evidence suggests that urbanization with its high levels of vehicle emissions, and westernized lifestyle are linked to the rising incidence of pollen-induced respiratory allergy seen in most industrialized countries. Moreover, the increase in respiratory allergy parallels an increase in outdoor and indoor air pollution. Although the role played by outdoor pollutants in allergic sensitization of airways has yet to be elucidated, it is well established that outdoor pollution exacerbates respiratory symptoms in atopic subjects. This review focuses on the evidence implicating outdoor pollution in pollen-related respiratory diseases. Acute and chronic exposure to such components of air pollution as sulphur dioxide, nitrogen dioxide, ozone and respirable particulate matter (isolated or in various combinations) enhances airway responsiveness to aeroallergens in atopic subjects. By attaching to the surface of pollen grains and of plant-derived paucimicronic particles, pollutants can modify the morphology of these antigen-carrying agents and alter their allergenic potential. In addition, by inducing airway inflammation, which increases airway epithelial permeability, pollutants overcome the mucosal barrier and so "prime" allergen-induced responses. Lastly, air pollutants such as diesel exhaust particulates can also facilitate the immunoglobulin (Ig)E response that leads to pollinosis symptoms in atopic individuals.

Air Pollution↗
PubMedDate not supplied

Respiratory effects of environmental pollution: epidemiological data.

A recent document of the American Thoracic Society and two previous reports of the International Union Against Tuberculosis and Lung Disease have summarized the negative health effects due to air pollution in a list ranging from the increase of mortality to the perception of bad odors. A significant attempt to estimate, on an annual basis, the negative effects of air pollution from particulate matter less than 10 microns in aerodynamic diameter (PM10) has been carried out on data from Austria, France, and Switzerland: e.g. in France, air pollution from PM10 is responsible annually for 31,700 deaths, 36,700 new cases of chronic bronchitis and 577,000 attacks of asthma in adults, 450,000 cases of acute bronchitis and 243,000 attacks of asthma in children. Recently, a study on the long-term effects of air pollution on about 500,000 residents in metropolitan US areas evidenced that each 10 micrograms/m3 elevation in fine particulate air pollution is associated with approximately a 4%, 6% and 8% increased risk of all-cause, cardiopulmonary and lung cancer mortality, respectively. Some Italian experiences have also confirmed respiratory health damages from air pollution, namely the prospective epidemiologic studies on general population samples of the Po Delta and Pisa areas; the cross-sectional study on schoolchildren of the 'Italian study on respiratory disorders in childhood and environment' (SIDRIA); and a meta-analysis of the Italian studies on short-term effects of air pollution. In conclusion, epidemiologic studies suggest that air pollution plays an important role in the exacerbation and in the pathogenesis of chronic respiratory diseases. Thus, respiratory physicians, as well as public health professionals, should advocate for a cleaner environment.

Adult↗
PubMed2003

Relation between income, air pollution and mortality: a cohort study.

BACKGROUND: Community levels of air pollution have been associated with variability in mortality rates, but previous studies have inferred exposure to pollutants on a citywide basis. We investigated mortality in relation to neighbourhood levels of income and air pollution in an urban area. METHODS: We identified 5228 people in the Hamilton-Burlington area of southern Ontario who had been referred for pulmonary function testing between 1985 and 1999. Nonaccidental deaths that occurred in this group between 1992 and 1999 were ascertained from the Ontario Mortality Registry. Mean household income was estimated by linking the subjects' postal codes with the 1996 census. Mean neighbourhood levels of total suspended particulates and sulfur dioxide were estimated by interpolation from data from a network of sampling stations. We used proportional hazards regression models to compute mortality risk in relation to income and pollutant levels, while adjusting for pulmonary function, body mass index and diagnoses of chronic disease. Household incomes and pollutant levels were each divided into 2 risk categories (low and high) at the median. RESULTS: Mean pollutant levels tended to be higher in lower-income neighbourhoods. Both income and pollutant levels were associated with mortality differences. Compared with people in the most favourable category (higher incomes and lower particulate levels), those with all other income-particulate combinations had a higher risk of death from nonaccidental causes (lower incomes and higher particulate levels: relative risk [RR] 2.62, 95% confidence interval [CI] 1.67-4.13; lower incomes and lower particulate levels: RR 1.82, 95% CI 1.30-2.55; higher incomes and higher particulate levels: RR 1.33, 95% CI 1.12-1.57). Similar results were observed for sulfur dioxide. The relative risk was lower at older ages. INTERPRETATION: Mortality rates varied by neighbourhood of residence in this cohort of people whose lung function was tested. Two of the broader determinants of health--income and air pollution levels--were important correlates of mortality in this population.

Aged↗
PubMedDate not supplied

A multi-year study of air pollution and respiratory hospital admissions in three New York State metropolitan areas: results for 1988 and 1989 summers.

As part of a multi-year study of air pollution and respiratory hospital admissions in the Buffalo, Albany, and New York City, New York, metropolitan areas, filter samples were collected daily at suburban air monitoring sites and analyzed for their content of particulate phase aerosol strong acidity (i.e., hydrogen ion, H+) and sulfate (SO4 = ). In addition, daily hospital admissions for respiratory causes, other community air pollutant measurements (e.g., ozone, O3), and meteorological data (e.g., temperature) were also obtained for these metropolitan areas. The summer months (June-August) were selected for analysis because that is when the highest H+ (and O3) are usually experienced at these sites, and because these months are rarely complicated by other major influences (e.g., high pollen counts). Thus, any pollution-admissions relationships were expected to be most clearly discernible in this season. Prior to the health effects analysis, the summer admissions and environmental data were first detrended to eliminate long-wave autocorrelations, and day-of-week effects were removed via regression. Cross-correlations of the filtered 1988 and 1989 admissions and environmental data revealed strong associations between elevated summer haze pollution (i.e., H+, SO4 =, and O3) and increased total respiratory and asthma admissions on the same day and/or on subsequent days in Buffalo and New York City, especially during the summer of 1988 (when pollution levels were more extreme). Regression analyses indicated that the pollution-admissions associations remained significant (p < 0.05) even after the simultaneous inclusion of lagged daily maximum temperature. Mean effects calculations for these cities indicated that summertime haze can play a significant role in the occurrence of respiratory admissions in that season: accounting for an average 6 to 24% of 1988 Buffalo and NYC asthma admissions (depending on the pollutant index employed). O3 consistently had the highest mean effects estimates. Relative risk (RR) calculations indicated that the risk of admission for asthma was increased by a factor of 1.19 to 1.43 in these cities on maximum 1988 summertime pollution days, with H+ consistently having the highest RR estimates. These results are consistent with the hypothesis that ambient acid aerosol peaks (e.g., H+ > or = 100 nmol/m3) can potentiate the respiratory disease effects of O3. Associations were weaker in the less urbanized Albany metropolitan area and in the New York City (NYC) suburbs, even though the NYC suburban O3 exposures were similar to (and the H+ concentrations may even be somewhat higher than) those in the center city.(ABSTRACT TRUNCATED AT 400 WORDS)

Air Pollution↗
PubMed1956

Pollution of ground water in Europe.

This paper discusses pollution of ground water in 20 countries of the European region, giving for each an account of the geology and hydrogeology, water supplies, the extent and nature of ground water pollution, and the legal, administrative, and technical means of controlling that pollution. For the countries not considered in the preceding article on surface water pollution, an account is also given of the superficial physical features, rainfall, population, and industries.A general discussion follows of such questions as the ways in which ground water pollution may occur, the factors mitigating or aggravating pollution, and ways of protection against pollution. The authors consider that the problem of ground water pollution in Europe may well be more serious than it would appear to be on the evidence so far obtained.

Europe↗
PubMed1992

Pulmonary function status of shopkeepers of Ahmedabad exposed to autoexhaust pollutants.

The study deals with evaluation of pulmonary function status (VC, FEV1% and FEF25-75%) in Ahmedabad shopkeepers stationed near different traffic junctions and relating them with the levels of oxides of nitrogen (NOx) near these junctions categorised as Heavy, Medium and Low polluted area junctions. The pulmonary function test (PFT) values of heavy polluted and medium polluted area shopkeepers is compared with low polluted area shopkeepers. The influence of smoking habits and duration of exposure over PFT values was seen. The prevalence of airway obstruction in shopkeepers was compared with USA population. The results indicated significant impairment in FEV1% and FEF25-75% value in high polluted area shopkeepers where NOx level is much higher than TLV value. In medium polluted area, where NOx level is slightly higher than TLV value, shopkeepers demonstrated significant impairment in FEF25-75%. Smoking is found to have an additive effect. A linear increase in the prevalence of pulmonary impairment with increasing duration of exposure was evidenced. Shopkeepers exhibited higher prevalence of impairment in both smokers and non-smokers than USA population attributing it to the effect of autoexhaust pollutants. This study also denoted that FEF25-75% is an early indicator of obstruction in smaller airways which is the primary site of deposition of inhaled pollutants.

Air Pollutants↗
PubMed2003

Cytogenetic alterations in Prodiamesinae species (Diptera, Chironomidae) from different polluted regions.

Changes in the salivary gland chromosomes are described in sibling species Prodiamesa olivacea Mg. and P. bureshi Michailova larvae collected from trace metal polluted and unpolluted areas in Bulgaria and the United Kingdom. Although both species from polluted and unpolluted areas show a high frequency of ectopic conjugations, those between arm B (telomere) and arm F occur at a significantly higher frequency in P. bureshi from unpolluted sites. The reasons for chromosome conjugations and their changes under stress conditions are discussed. Regression of the puffin section 2 of chromosome arm A was significantly higher in P. bureshi from polluted sites, suggesting that trace metal pollution represses transcription at that site. Also, somatic heterozygous inversions and deficiencies occur in chromosomes of both species at the polluted areas. Some deformities ofthe head capsule were observed in both species at the metal-polluted sites. However, our data shows that the genome is a much more sensitive indicator of trace metal pollution than external morphology. The present authors suggest that measuring genotoxic damage at a cellular level provides a subtle and cost-effective indicator of trace metal pollution.

Animals↗
PubMed2004

[The effect of cadmium pollution on reproductive health in females].

OBJECTIVE: To study the relationship between cadmium pollution and its adverse effects on female reproductive health status in people living in cadmium polluted area in Zhenghe, Fujian provinces. METHODS: Data through laboratory studies on reproductive health of female residents in Cd-pollution area were studied and compared with those in control areas in Zhenghe. RESULTS: Both prevalence rates of abnormal menstrual cycle and dysmenorrhea in unmarried women in Cd-pollution area (19.1% vs. 42.6%) were significantly higher than those in control area (5.7% vs. 18.9%) and the rates of sterility in married women in Cd-pollution area (6.3%) were significantly higher than those in control area (1.1%). During the first two pregnancies, rates of queasiness, disgorgement, spontaneous abortion and stillbirth in married women in polluted area were 44.7%, 31.7%, 10.27% and 4.23%, significantly higher than those 26.5%, 17.8%, 2.85% and 1.05% in control area, with significant differences (P < 0.05). Results from cumulative odds model analysis showed that: living in Cd-pollution area was a possible risk factor related to female reproductive health (OR = 2.072), after the other risk factors being under control. CONCLUSION: The female reproductive health status of people residing in the cadmium polluted area had already been deteriorated.

Abortion, Spontaneous↗
PubMed2005

Monitor-based evaluation of pollutant load from urban stormwater runoff in Beijing.

As a major pollutant source to urban receiving waters, the non-point source pollution from urban runoff needs to be well studied and effectively controlled. Based on monitoring data from urban runoff pollutant sources, this article describes a systematic estimation of total pollutant loads from the urban areas of Beijing. A numerical model was developed to quantify main pollutant loads of urban runoff in Beijing. A sub-procedure is involved in this method, in which the flush process influences both the quantity and quality of stormwater runoff. A statistics-based method was applied in computing the annual pollutant load as an output of the runoff. The proportions of pollutant from point-source and non-point sources were compared. This provides a scientific basis for proper environmental input assessment of urban stormwater pollution to receiving waters, improvement of infrastructure performance, implementation of urban stormwater management, and utilization of stormwater.

China↗
PubMed1994

[Use of macroalgae for the evaluation of organic pollution in the Preto river, northwest of São Paulo State].

The Preto River, located in the northwest of São Paulo State, receives a total wastewater load of 15.150 kg DBO day-1, from which 13.685 kg DBO day-1 (90.5%) corresponds to domestic sewage, and the city of São José do Rio Preto contributes with 12.400 kg DBO day-1 (90% of domestic sewage). During the period from August 1990 through January 1991, monthly sampling was carried out to evaluate the use of macroalgae as bioindicator of organic pollution. Five sampling sites were established along the main river and the following variables were analised: temperature, conductance, turbidity, dissolved oxygen, BOD, COD, total and fecal coliforms, and composition and abundance of macroalgal communities. Data were submitted to analysis of variance, correlation coefficient, cluster analysis (four different approaches) and converted to biological indices (species deficit, relative pollution, saprobity, diversity and uniformity indices). A wide range in water quality was found (particularly for conductance, oxygen, BOD and COD) among the sampling sites, which were classified into three groups (polluted, moderately polluted and unpolluted/weakly polluted). As regards the occurrence and abundance of macroalgae the Rhodophyta were found only in unpolluted or weakly polluted sites, whereas Cyanophyta occurred mostly under high pollution load; the Chlorophyta species were observed under a wide range of conditions. Among the biological indices, saprobity was the most sensitive and correlated to all water variables and the other indices. Cluster analyses showed that the composition of macroalgal communities was consistent with the levels of organic pollution in the Preto River.

Analysis of Variance↗
PubMed1995

[Respiratory toxicity due to atmospheric pollutants. General review and a study of the relation to respiratory infections].

The main primary pollutants released into the atmosphere are sulfur dioxide (SO2), nitrogen monoxide and dioxide (NOx), particulate dust and in a less important part carbon monoxide (CO), hydrocarbons and heavy metals (Pb, Cd). Sulfur and nitrogen oxides are released from combustion of coals and fuels. Sulfates, nitrates and ozone are secondary pollutants resulting from chemical reactions within the atmosphere. While governmental directives limiting emissions have decreased SO2 and particulate matter levels, air quality in urban regions has improved in the last two decades. The role of air pollution as a risk factor for respiratory infections is difficult to address. Animal experiments demonstrate that air pollutants decrease the efficacy of lung defense mechanisms and increase the sensibility to respiratory infections. Nevertheless, because of difference in sensitivity between animal species and between exposure conditions, these effects are difficult to extrapolate to humans. Moreover, it is obvious that direct exposure studies of the sensibility of humans to respiratory infections are rare for ethical reasons. Epidemiological data addressing the role of air pollutants at usual levels can only suggest that some pollutants (SO2, suspended particulates) constitute a risk factor for respiratory infections. Since most of these studies do not include bacteriologic and virologic confirmation, it is unclear whether this respiratory morbidity is due to respiratory irritation or infection. In conclusion, we think that high concentrations of air pollutants are very likely to increase sensibility to respiratory infections in humans. There are however no sufficient data to clearly establish whether air pollution constitutes a risk factor for respiratory infections at usual ambient concentrations.

Air Pollutants↗
PubMedDate not supplied

Short-term air pollution exposures and responses in Los Angeles area schoolchildren.

We studied 269 school children from three Southern California communities of contrasting air quality in two successive school years, to investigate short-term effects of ambient ozone (O3), nitrogen dioxide (NO2), or particulate matter (PM) on respiratory health. We measured lung function and symptoms twice daily for one week each in fall, winter and spring; and concurrently assessed time-activity patterns and personal exposures. Average daily personal exposures correlated with pollutant concentrations at central sites (r = 0.61 for O3, 0.63 for NO2, 0.48 for PM). Questionnaire-reported outdoor activity increased slightly in communities/seasons with higher pollution. Lung function differences between communities were explainable by age differences. Morning forced vital capacity (FVC) decreased significantly with increase in PM or NO2 measured over the preceding 24 hours. Morning-to-afternoon change of forced expired volume in one second (FEV1) became significantly more negative with increase in PM, NO2, or O3 on the same day. Predicted FVC or FEV1 loss on highest- vs lowest-pollution days was < 2%. Daily symptoms showed no association with current or prior 24-hour pollution, but increased with decreasing temperature. Parents' questionnaire responses suggested excess asthma and allergy in children from one polluted community while children in the other polluted community reported more symptoms, relative to the cleaner community. We conclude that Los Angeles area children may experience slight lung function changes in association with day-to-day air quality changes, reasonably similar to responses seen by others in less polluted areas. Although short-term pollution effects appear small, they should be assessed in longitudinal lung function studies when possible, to allow maximally accurate measurement of longer-term function changes.

Air Pollution↗
PubMed1997

Short-term effects of particulate air pollution on respiratory morbidity in asthmatic children.

Short-term effects of air pollution (consisting primarily of sulphur dioxide and particulate matter but with low acidity) on respiratory morbidity were studied in asthmatic children from Sokolov, Czech Republic. Eighty nine children with asthma, who recorded daily peak expiratory flow measurements, symptoms and medication use in a diary, were analysed for 7 months during the winter of 1991-1992. Air pollution measurements included: SO2, total suspended particulates (TSPs), inhalable particles, ie. particulate matter of aerodynamic diameter < or = 10 microm, particle strong acidity (PSA) and fine particle sulphate concentration (SO4). Linear and logistic regression analyses estimated the impact of air pollutants adjusted for trend, temperature and weekend and autocorrelated errors. Exposure to elevated levels of air pollution was associated with decreased peak expiratory flow rates, increased respiratory symptoms, increased prevalence of school absence and fever, and increased medication use. Prolonged exposure to particle SO4 showed the largest effect estimates. At the end of January, an air pollution episode occurred, during which respiratory symptoms, prevalence of fever, school absence and asthma medication increased. The association between respiratory symptoms and particulate SO4 was highly dependent on this episode, whilst the associations between lung function and SO4 as well as between fever and SO4 were still observed when this air pollution episode was excluded. Some evidence was found that exposure to air pollution might have enhanced the respiratory symptoms while children were experiencing respiratory infections. In this study, a panel of children with mild asthma experienced small decreases in peak expiratory flow and increased dyspnoea in association with fine particles formed during air pollution episodes.

Adolescent↗
PubMed1997

Air pollution and trends in asthma.

There is considerable concern about possible links between ambient air pollution and the upward trend in asthma. This chapter reviews the mechanistic and epidemiological evidence concerning air pollution and asthma and examines the hypothesis that trends in asthma could be explained by air pollution. It is concluded that existing evidence is not sufficient to link air pollution with the initiation of asthma in healthy subjects. Although there is better evidence that air pollution can provoke or aggravate asthma, it probably plays a minor role at a public health level, in comparison with other factors. It is therefore unlikely that trends in asthma could be explained by air pollution. Furthermore, correlations between some air pollutants and asthma over time are not consistent with the hypothesis. The possibility of a specific effect of motor vehicle pollution needs further investigation but this factor is unlikely to be the main cause of the worldwide increase in asthma.

Air Pollution↗