PM2.5 and PM10 during COVID-19 lockdown in Kuwait: Mixed effect of dust and meteorological covariates.

This study investigated the impact of COVID-19 lockdown on particulate matter concentrations, specifically PM2.5 and PM10, in Kuwait. We studied the variations in PM2.5 and PM10 between the lockdown in 2020 with the corresponding periods of the years 2017-2019, and also investigated the differences in PM variations between the 'curfew' and 'non curfew' hours. We applied mixed-effect regression to investigate the factors that dictate PM variability (i.e., dust and meteorological covariates), and also processed satellite-based aerosol optical depths (AOD) to determine the spatial variability in aerosol loads. The results showed low PM2.5 concentration during the lockdown (33 µg/m3) compared to the corresponding previous three years (2017-2019); however, the PM10 concentration (122.5 µg/m3) increased relative to 2017 (116.6 µg/m3), and 2019 (92.8 µg/m3). After removing the 'dust effects', both PM2.5 and PM10 levels dropped by 18% and 31%, respectively. The mixed-effect regression model showed that high temperature and high wind speed were the main contributors to high PM2.5 and PM10, respectively, in addition to the dust haze and blowing dust. This study highlights that the reductions of anthropogenic source emissions are overwhelmed by dust events and adverse meteorology in arid regions, and that the lockdown did not reduce the high concentrations of PM in Kuwait.

Disability Adjusted Life Years (DALYs) in Terms of Years of Life Lost (YLL) Due to Premature Adult Mortalities and Postneonatal Infant Mortalities Attributed to PM2.5 and PM10 Exposures in Kuwait.

Ambient air pollution in terms of fine and coarse particulate matter (PM2.5 and PM10) has been shown to increase adult and infant mortalities. Most studies have estimated the risk of mortalities through attributable proportions and number of excess cases with no reference to the time lost due to premature mortalities. Disability adjusted life years (DALYs) are necessary to measure the health impact of Ambient particulate matter (PM) over time. In this study, we used life-tables for three years (2014⁻2016) to estimate the years of life lost (YLL), a main component of DALYs, for adult mortalities (age 30+ years) and postneonatal infant mortalities (age 28+ days⁻1 year) associated with PM2.5 exposure and PM10 exposure, respectively. The annual average of PM2.5 and PM10 concentrations were recorded as 87.9 µg/m³ and 167.5 µg/m³, which are 8 times greater than the World Health Organization (WHO) air quality guidelines of 10 µg/m³ and 20 µg/m³, respectively. Results indicated a total of 252.18 (95% CI: 170.69⁻322.92) YLL for all ages with an increase of 27,474.61 (95% CI: 18,483.02⁻35,370.58) YLL over 10 years. The expected life remaining (ELR) calculations showed that 30- and 65-year-old persons would gain 2.34 years and 1.93 years, respectively if the current PM2.5 exposure levels were reduced to the WHO interim targets (IT-1 = 35 µg/m³). Newborns and 1-year old children may live 79.81 and 78.94 years, respectively with an increase in average life expectancy of 2.65 years if the WHO PM10 interim targets were met (IT-1 = 70 µg/m³). Sensitivity analyses for YLL were carried out for the years 2015, 2025, and 2045 and showed that the years of life would increase significantly for age groups between 30 and 85. Life expectancy, especially for the elderly (≥60 years), would increase at higher rates if PM2.5 levels were reduced further. This study can be helpful for the assessment of poor air quality represented by PM2.5 and PM10 exposures in causing premature adult mortalities and postneonatal infant mortalities in developing countries with high ambient air pollution. Information in this article adds insights to the sustainable development goals (SDG 3.9.1 and 11.6.2) related to the reduction of mortality rates attributed to ambient air levels of coarse and fine particulate matter.

Effect of environmental factors on photodegradation of polycyclic aromatic hydrocarbons (PAHs) in the water-soluble fraction of Kuwait crude oil in seawater.

Photodegradation of PAHs in the water-soluble fraction of Kuwait crude oil in seawater was investigated under various environmental factors (temperature, light intensity, oxygen levels and presence of a sensitizer) in laboratory conditions. All factors investigated had significant effect on the degradation rates of PAHs. At 15 °C almost all PAHs optimally degraded at an oxygen level of 4 ppm. For lower molecular weight PAHs a light intensity of 500 W/m(2) in the presence of the sensitizer worked well. Higher molecular weight PAHs degraded at faster rates at a light intensity 750 W/m(2). At 30 °C, most of the PAHs degraded optimally at an oxygen level of 0 ppm and light intensity of 500 or 750 W/m(2) in presence of the sensitizer. At 40 °C, most of PAHs degraded optimally at low oxygen concentrations (0 and 4 ppm) and a light intensity of 500 W/m(2) in the presence of the sensitizer. Linear regression indicated that for most of the compounds, light intensity had the greatest effect on degradation rates.