Air pollution and respiratory symptoms: results from three panel studies in Bangkok, Thailand.

Abstract

Several studies in North American cities have reported associations between air pollution and respiratory symptoms. Replicating these studies in cities with very different population and weather characteristics is a useful way of addressing uncertainties and strengthening inferences of causality. To this end we examined the responses of three different panels to particulate matter (PM) air pollution in Bangkok, Thailand, a tropical city characterized by a very warm and humid climate. Panels of schoolchildren, nurses, and adults were asked to report daily upper and lower respiratory symptoms for 3 months. Concentrations of daily PM(10) (PM with a mass median aerodynamic diameter less than 10 microm) and PM(2.5) (airborne particles with aerodynamic diameters less than 2.5 microm) were collected at two sites. Generally, associations were found between these pollution metrics and the daily occurrence of both upper and lower respiratory symptoms in each of the panels. For example, an interquartile increase of 45 microg/m(3) in PM(10) was associated with about a 50% increase in lower respiratory symptoms in the panel of highly exposed adults, about 30% in the children, and about 15% in the nurses. These estimates were not appreciably altered by changes in the specification of weather variables, stratification by temperature, or inclusion of individual characteristics in the models; however, time trends in the data cause some uncertainty about the magnitude of the effect of PM on respiratory symptoms. These pollutants were also associated with the first day of a symptom episode in both adult panels but not in children. The estimated odds ratios are generally consistent with and slightly higher than the findings of previous studies conducted in the United States.

Impact of ambient air pollution and wheeze-associated disorders in children in Southeast Asia: a systematic review and meta-analysis

“…Based on the data in Table 1, nearly 84,000 pediatric wheeze-associated disorders events have been investigated to assess the impact of ambient air pollution in five countries. Of these, four studies were conducted in Thailand (7,(41)(42)(43), three in Vietnam (44)(45)(46), and one each in Singapore, Indonesia and Malaysia (8,9,47).…”

“…Eight studies reported the effects of PM 10 (7, 8, 41-44, 46, 47), three reported the effects of PM 2.5 (41,43,46), four studies reported the effects of SO 2 (9,43,44,46), five studies reported the effects of NO 2 (8,9,44,46,47), three reported the effects of CO (8,46,47) and four reported the effects of O 3 (44)(45)(46)(47). Only one study reported the effects of TSP, PM 1 and NO x but Nhung et al (46) presented three estimates for PM 1 and NO x while only one estimate for TSP was given by Chew et al (9), therefore the effects of TSP were analyzed further.…”

“…Four studies investigated the association of air pollution with hospital admissions for wheeze-associated disorders, four explored rate the ratio of incidence or prevalence and the rest considered emergency room visits or mortality (Table 1). Five studies defined the outcome using the International Classification of Diseases (ICD) version 9 or 10 (9,42,(44)(45)(46), one based on the hospital admission data (47) and four used questionnaires for wheezing symptoms (7,8,41,43).…”

Particulate Matter (PM2.5, PM10-2.5, and PM10) and Children's Hospital Admissions for Asthma and Respiratory Diseases: A Bidirectional Case-Crossover Study

“…There have been several studies of ambient PM 10 exposure and risk for upper and lower respiratory Downloaded by [Oregon State University] The OR were calculated for a 10 μg/m 3 and interquartile range increment of particulate matter (and subfractions); adjusted ORs were adjusted for daily weather conditions. -Vadakan et al, 2001) investigated daily upper and lower respiratory symptoms in 3 categories consisting of children, adults, and nurses in relation to daily outdoor PM 2.5 and PM 10 concentrations over 3 mo. A 45-μg/m 3 (approximately interquartile range) change in PM 10 was associated with risk of 1.10 and 1.13, respectively, for UPRD and LWRD in children.…”

Does Chronic Exposure to Air Pollution in Childhood Impact Long-Term Respiratory Health?

“…For example, recent reports on air quality and respiratory health indicate that five times more children than adults die from asthma each year in the United States and that in Toronto, Ontario, children experience more than 1,200 acute bronchitis episodes per year as a result of air pollution from traffic sources (U.S. Environmental Protection Agency 2002;Toronto Public Health 2007). Indeed, literature reveals that children bear a disproportionate share of the health consequences of exposure to air pollution, due to their relatively smaller lung surface, their stage of health development, and the proportion of time they spend outdoors (Vichit-Vadakan et al 2001;Neidell 2004).…”