Low Levels Of PM2 Research Articles

Ambient particulate air pollution and acute lower respiratory infections: a systematic review and implications for estimating the global burden of disease

Acute lower respiratory infections (ALRI) account for nearly one fifth of mortality in young children worldwide and have been associated with exposures to indoor and outdoor sources of combustion-derived air pollution. A systematic review was conducted to identify relevant articles on air pollution and ALRI in children. Using a Bayesian approach to meta-analysis, a summary estimate of 1.12 (1.03, 1.30) increased risk in ALRI occurrence per 10 μg/m3 increase in annual average PM2.5 concentration was derived from the longer-term (subchronic and chronic) effects studies. This analysis strengthens the evidence for a causal relationship between exposure to PM2.5 and the occurrence of ALRI and provides a basis for estimating the global attributable burden of mortality due to ALRI that is not influenced by the wide variation in regional case fatality rates. Most studies, however, have been conducted in settings with relatively low levels of PM2.5. Extrapolating their results to other, more polluted, regions will require a model that is informed by evidence from studies of the effects on ALRI of exposure to PM2.5 from other combustion sources, such as secondhand smoke and household solid fuel use.

GULF COAST STUDY OF URBAN AIR POLLUTION AND RESPIRATORY FUNCTION (SURF)

ISEE-78 Introduction: The purpose of this study was to identify and evaluate exposure to and effects of urban air pollutants on respiratory function in an occupational cohort of beach lifeguards. This area of the Gulf Coast is adjacent to many point sources of air toxics, including major petrochemical industrial complexes and heavily trafficked roads and highways. It is also a consistent non-attainment area for compliance with number of days during which ozone concentrations exceed permissible levels. The need to determine health effects associated with air pollution has thus increased. Methods: The lifeguard occupational cohort includes >100 guards, ages 16-27, working 10-hour shifts and sustaining continuous ambient air exposures. A “natural” experiment was facilitated, given that guards are traditionally exposed to low levels of photochemically formed air pollutants during summer mornings and high levels (reaching seasonal peaks) in the afternoons. Three times daily, each lifeguard performed computerized spirometry, according to ATS standards, to measure air flow rates and lung volumes: in the morning prior to exercise (baseline), following a one-hour strenuous cardiovascular workout, and again in the afternoon following sustained exposure to ambient air. Each guard also completed an initial survey, detailing family and personal history of asthma, smoke exposure, and lung disease as well as daily surveys documenting potential confounders including recent illness, medication use, and smoke exposure. Hourly measurements of ozone, oxides of nitrogen, nitrogen dioxide, sulfur dioxide, and particulates (PM2.5) were obtained from a regulated monitoring site at the local airport. Meteorologic data collected include wind speed, wind direction, temperature, and relative humidity. Results: Univariate statistics revealed normally distributed data meeting assumptions of homogeneity of variance for ANOVA, which showed a significant difference (p<0.05) between morning and afternoon lung function measures. Linear regression revealed a significant decrease in FVC and FEV1 after exposure to increasing levels of PM2.5 for several hours. Discussion: Results indicate a decrease in total lung volume (preserved FEV1/FVC ratio) rather than typical patterns of airway obstruction due to bronchospasm as seen in asthma exacerbations (FEV1 reduced more than FVC)—even at relatively low levels of PM2.5. While federal air quality standards list PM2.5 levels >65 μg/m3 as unhealthy, we have seen average lung volumes decrease by as much as 0.5 liters (5-30%) with maximum PM2.5 concentrations of only 38 μg/m3. This may have implications for environmental recommendations and regulations as well as disease prevention, in that our data suggest that even tighter standards may be necessary.