Relative Power of Alternative Ambient Air Pollution Metrics for Detecting Chronic Health Effects in Epidemiological Studies

Abstract

SUMMARYA number of alternative metrics for characterizing ambient air pollution concentrations were compared with regards to their relative power for detecting health effects as associated with long-term ambient concentrations of ozone and total suspended particulates (TSP). The health effects studied included development of overall airway obstructive disease (AOD), chronic bronchitis and asthma, as well as increasing severity for AOD, chronic bronchitis, and asthma. These health effects were studied in a cohort of 3914 California non-smoking Seventh-day Adventists who had 20 years of residence and work location history. The alternative metrics for ozone included the 24 hour mean, an 8 hour average (9.00 a.m. to 5.00 p.m.) as well as exceedance frequencies (hours above) and excess concentrations (the integrated sum of time x concentration above) for cutoffs of 6,8, 10,12, and 15 parts per hundred million (pphm). For TSP the alternative metrics were the 24 hour mean, as well as exceedance frequencies and excess concentrations for cutoffs of 60,100,150 and 200 micrograms per cubic metre (pg/m3). The relative power for detecting health effects was assessed using the ratio of the estimated pollutant regression coefficient to its estimated standard error in multiple logistic regression models for development of disease and multiple linear regression models for increasing severity of disease. For ozone the metric with the greatest power for the most health outcomes was the 8 hour average. For TSP the metric with the greatest power for the most health outcomes was excess concentration above 200pg/m3 of TSP.

COVID-19 Pandemic and City-Level Nitrogen Dioxide (NO2) Reduction for Urban Centres of India

“…Preliminary analysis reveals that the transmission rate for India is 1.7 (where the value is ranging from 1.5 to 3.5 worldwide) (Ghosh et al 2020 ). The respiratory illness symptoms and mortality due to prolonged exposure to gaseous pollutants like nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), particulate matter (PM), carbon monoxide (CO), etc., have been reported earlier in India and around the world in several studies (Abbey et al 1995 ; Abbey and Burchette 1996 ; Balakrishnan et al 2019 ; Beeson et al 1998 ; David et al 2019 ; Faustini et al 2014 ; He et al 2020 ; Liu et al 2013 ; Ogen 2020 ; Siddique et al 2011 ).…”

Long-Term Ambient Ozone Concentration and the Incidence of Asthma in Nonsmoking Adults: The Ahsmog Study

“…For each metric we calculated the Wald statistic (square of the quotient of the estimated ozone regression coefficient and the estimated standard error of the ozone coefficient) and used this as a measure of strength of association (Abbey and Burchette, 1996). Comparison of the Wald statistics indicated that for males, development of DTA was most strongly related to mean ozone concentration, followed by 8-h concentration, and then by hours exceeding 60, 80, 100, 120, and 150 ppb, respectively.…”

“…Estimated odds ratios and 95% confidence intervals (CI) were adjusted downward to more closely approximate relative risk because incident cases of asthma 1977-1992 were not rare (Abbey et al, 1989). The Wald statistic (Abbey and Burchette, 1996) was calculated for comparison of the relationships between asthma incidence and the different ozone metrics. All P values reported for coefficients in logistic regression models were based upon the likelihood ratio test (Kleinbaum et al, 1982).…”

Functional measure of ozone exposure to model short‐term health effects

“…It may be argued that choosing an optimal measure of exposure is relatively difficult, partly because exposure measures vary with regard to the relative power of each to detect significant estimated health effects of exposure (Abbey and Burchette, ). However, we propose that accounting for the daily pattern of pollutant concentration is an important contribution to the estimation of ozone exposure as detailed in this article.…”