Ambient exposure of O₃ and NO₂ and associated health risk in Kuwait

Ozone (O₃) and nitrogen dioxide (NO₂), indissoluble air pollutants in the atmosphere, have been confirmed in various parts of the world to have detrimental health effects on humans. Currently, such information is lacking in Kuwait. The objectives of this study are to investigate the spatial and temporal variations of O₃ and NO₂ concentrations in Kuwait during a 4-year period (2014-2017) and to quantify the associated short- and long-term health effects, including all-cause, respiratory, and cardiovascular mortalities and morbidities during the same study period. Exposure assessment showed that the annual levels (22.5-26.4 ppb), SOMO35, and the 8-hour 4-year mean (38 ppb) of O₃ were very low and below the World Health Organization (WHO) (50 ppb) and Kuwaiti (70 ppb) regulatory limits. The annual mean levels of NO₂ ranged from 30.3 to 43.8 ppb and were significantly higher than both WHO and Kuwait limits (21 ppb). As expected, O₃ and NO₂ levels showed opposing trends, with higher concentrations of NO₂ recorded in early morning and mid-evening, during autumn and winter, and during Saturdays (the so-called weekend effect). Health effects indicated high respiratory diseases due to short-term exposure to NO₂. Contrary to the western countries' pollution levels, Kuwait showed lower O₃ and higher NO₂ levels. There is potential for substantial health improvements in Kuwait by reducing NO₂ pollution through stringent control measures of stationary and mobile sources.