Pollution: does it cause asthma?

"It wasn't the plague we expected." Parents' perceptions of the health and environmental impact of opencast coal mining

This paper explores the health and environmental concerns of parents living close to opencast coal mines in the UK and characterises parental risk perceptions in relation to children's asthma status. This qualitative research was undertaken in tandem with an epidemiological investigation aiming to establish whether opencast coal mining adversely affected children's respiratory health. Using a social construction approach, the centrality of health claims in environmental health disputes becomes apparent for a number of claims-makers. We focus on claims of non-activist participants in an epidemiological study, hitherto unknown and unexplored. In all but one case health claims were anticipated rather than realised. No link was found between children's asthma and exacerbation of the condition although some parents of children with asthma had greater concerns during the opencast planning stage. In fact, parents' discourses on children's health largely mirrored the epidemiological findings which showed increased dust, no increase in asthma prevalence but higher rates of general practitioner (GP) consultations for respiratory conditions suggesting that the commonly observed lack of convergence between lay and expert knowledge should not be taken for granted. In spite of this overall lack of an experienced health effect, the sociological data highlight respondents' recognition of the place-specificity of exposures, hence, the reasons why opencast proposals are likely to continue to be met with opposition. Environmental health studies which incorporate epidemiological and social approaches simultaneously have a better chance of arriving at conclusions meaningful to affected communities and facilitate greater understanding of environmental disputes.

Respiratory symptoms in primary schoolchildren living near a freeway in Taiwan

A cross-sectional epidemiological study was conducted in an effort to investigate the effects of automobile exhaust on respiratory symptoms of school children in Kaohsiung, Taiwan. One school (Yang-Ming primary school) was located in the vicinity of 150 m from the highway and designated as a heavy-traffic area. The control school (Zhuang-Jing primary school) was situated in the same district but the distance of the school address to the freeway was 1500 m and designated as a low-traffic area. All of the primary school children in those schools were used in the study. In total, 3221 children were from the heavy-traffic school and 2969 from the low-traffic area. The respiratory health was assessed by an evaluation of the child's respiratory symptoms and illnesses using a parent-completed questionnaire. Data on traffic flow on the freeway were obtained from the Department of Transportation. Road traffic flows in front of the study schools were also measured with a portable counter. This study showed that a freeway surrounding a child's school may not be associated with an increased risk of respiratory symptoms. This may be due to insufficiently large contrasts in traffic pollution levels between these areas.

Prevalence of asthma and other respiratory symptoms in children living near and away from opencast coal mining sites

BACKGROUND

Public concern about respiratory conditions prompted the investigation of asthma and other respiratory diseases in children living near and away from opencast coal mining sites.

METHODS

We selected all 4860 children aged 1--11 years from five socioeconomically matched pairs of communities close to (OC) and away from (CC) active opencast sites. A postal questionnaire collected data on health and lifestyle. Outcomes were the cumulative and period prevalence (2 and 12 months) of wheeze, asthma, bronchitis and other respiratory symptoms.

RESULTS

The cumulative prevalence of wheeze varied from 30% to 40% across the ten communities, it was 36% in OC and 37% in CC. The cumulative prevalence of asthma was 22% in both OC and CC, varying between 12% and 24%. We found little evidence for associations between living near an opencast site and an increased prevalence of respiratory illnesses, or asthma severity. Some outcomes such as allergies, hayfever, or cough varied little across the study communities. Others, such as the use of asthma medication, the number of severe wheezing attacks in the past year or tonsillitis showed large variation. These similarities and variations were not explained by differences in lifestyle factors or differences in health services delivery and remain unexplained.

CONCLUSIONS

There was little evidence of an association between residential proximity to opencast mining sites and cumulative or period prevalence of respiratory illness, or asthma severity. Some variations in health outcomes between communities remained unexplained.

Emergency room visits of asthmatic children, relation to air pollution, weather, and airborne allergens

BACKGROUND

The worldwide increase in the incidence, prevalence, and severity of asthma may suggest that environmental factors play a role in these epidemiologic changes.

OBJECTIVE

To examine the correlations between air pollutants, weather conditions, airborne allergens, and the incidence of emergency room (ER) visits of children with acute asthma attacks.

DESIGN

One-year prospective study. Data of daily concentration of air pollutants, weather conditions, and selective airborne allergens were collected and compared with the number of ER visits of asthmatic children.

SUBJECTS

1076 asthmatic children (aged 1 to 18 years) who presented at the Pediatric ER between January 1 and December 31, 1993.

RESULTS

Correlations between fluctuations in ER visits of asthmatic children and various environmental parameters were more relevant for weekly than for daily values. Emergency room visits correlated positively with concentrations of NOx, SO2 and with high barometric pressure; and negatively with O3 concentration and minimal and maximal temperature. There were no significant correlations with concentrations of particulates, humidity, or airborne pollen and spores. An exceptionally high incidence of ER visits of asthmatic children was observed during September. This peak coincided with the beginning of the school year and the Jewish holidays. The correlations between ER visits and the environmental factors increased significantly when the September peak was excluded, revealing that 61% of the variance in ER visits was explained by NOx, SO2, and 03 concentrations, 46% by weather parameters, 66% by NOx, SO2 and barometric pressure, and 69% by the combination of air pollutants and weather parameters.

CONCLUSION

The major factors found to be associated with ER visits of asthmatic children were high NOx, high SO2, and high barometric pressure. Negative correlation was found between ER visits of asthmatic children and ozone concentrations. The particularly high number of ER visits at the beginning of the school year and the Jewish holidays was probably associated with an increase in the number of viral infections and/or emotional stress.

Prevalence of adult asthma symptoms in relation to climate in New Zealand

We conducted an ecological study linking prevalence of adult asthma symptoms with climate in the 93 New Zealand general electorates. For each electorate, the 12-month period prevalence of self-reported asthma symptoms was determined using a random sample of adults aged 20-44 on the 1991 New Zealand electoral roll. Long-term average climate was estimated using a national climate database and a geographic information system. Asthma prevalence was calculated within quartiles of the exposure variables. Independent effects of climate variables were assessed using linear regression models, with adjustment for confounding by climate, social deprivation, and geographic variables. There was a statistically significant association between asthma prevalence and mean temperature, with the lowest quartile of mean temperature having an approximately 2% lower asthma prevalence. After adjusting for confounding, there was a monotonic increase in asthma prevalence within quartiles of temperature. The results of this study are in agreement with other research suggesting a lower prevalence of asthma at low temperatures. Although on short (day-to-day) time scales, low temperatures may have a direct effect resulting in acute exacerbations of asthma symptoms, warmer average temperatures are associated with increased asthma prevalence. The reasons for this are unclear, although it is possible that on longer term (annual) time scales, higher temperatures are associated with higher levels of allergen exposure.