Long Memory and Time Trends in Particulate Matter Pollution (PM2.5 and PM10) in the 50 U.S. States

Abstract

This paper focuses on the analysis of the time series behaviour of the air quality in the 50 US states by looking at the statistical properties of the particulate matter (PM10 and PM2.5) datasets. We use long daily time series of outdoor air quality indices to examine issues such as the degree of persistence as well as the existence of time trends in data. For this purpose, we use a long memory fractionally integrated framework. The results show significant negative time trend coefficients in a number of states and evidence of long memory in the majority of the cases. In general, we observe heterogeneous results across counties though we notice higher degrees of persistence in the states on the West with respect to those on the East, where there is a general decreasing trend. It is hoped that the findings in the paper will continue to assist in quantitative evidence-based air quality regulation and policies.

Multiple Environmental Exposures and the Development of Hypertension in a Prospective US-Based Cohort of Female Nurses: A Mixture Analysis

“…We carried forward PM 10 and PM coarse exposure estimates by assigning average exposure of years 2006 and 2007 to the latter years, 23 assuming that the spatial variability of these particles remained stable over time. 24 Monthly exposure to NO 2 was estimated using regionalized models for the contiguous US from 1990 onward based on universal kriging. 25,26 The models were built on ground-level measurements with satellite-derived NO 2 and geographical variables as predictors.…”

“…Exposure to PM 2.5 was available from 1988 to 2017, whereas exposure to PM 10 and PM coarse was available only from 1988 to 2007. We carried forward PM 10 and PM coarse exposure estimates by assigning average exposure of years 2006 and 2007 to the latter years, assuming that the spatial variability of these particles remained stable over time …”

Atmospheric pollution in the ten most populated US cities. Evidence of persistence

“…), but also in environmental sciences ( Barros et al., 2016 ; Tiwari et al., 2016 ; Gil-Alana and Solarin, 2018 ; Gil-Alana and Trani, 2019 ; Xayasouk et al., 2020 ). Recent studies using fractional integration in atmospheric pollution include among others the papers by Gil-Alana et al. (2020) and Caporale et al.…”