Ambient exposure of O and NO and associated health risk in Kuwait.

Ozone (O) and nitrogen dioxide (NO), 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 O and NO 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 O were very low and below the World Health Organization (WHO) (50 ppb) and Kuwaiti (70 ppb) regulatory limits. The annual mean levels of NO ranged from 30.3 to 43.8 ppb and were significantly higher than both WHO and Kuwait limits (21 ppb). As expected, O and NO levels showed opposing trends, with higher concentrations of NO 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 NO. Contrary to the western countries' pollution levels, Kuwait showed lower O and higher NO levels. There is potential for substantial health improvements in Kuwait by reducing NO pollution through stringent control measures of stationary and mobile sources.