The impact of climatic conditions on the carcinogenic and non-carcinogenic risk of BTEX compounds: A systematic review and meta-analysis

Climatic conditions are one of the most important factors affecting the risk level associated with exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds. This systematic review and meta-analysis study aimed to investigate the impact of climatic conditions on carcinogenic and non-carcinogenic risk value changes during exposure to BTEX compounds. Five electronic bibliographic databases (Scopus, PubMed, Medline, Embase, and Web of Science) were systematically searched. The search algorithm consisted of three sets of keywords and their possible combinations. For different climatic conditions, the overall mean and 95 % confidence interval (CI) of the effect size related to the carcinogenic and non-carcinogenic risk of BTEX were calculated using a random effect model. 26 articles passed the inclusion/exclusion criteria and were included in this review. The highest values of the hazard quotient (HQ) for benzene, toluene, ethylbenzene, and xylene were in the summer season (53.3 %, 47.1 %, 73.3 %, 68.8 % of the studies) and in the winter season (33.3 %, 47.1 %, 20 %, and 25 % of the studies), respectively. Additionally, the highest values of carcinogenic risk (CR) for benzene and ethylbenzene were revealed in the summer season (50 % and 75 % of the studies) and in the winter season (33.3 % and 25 % of the studies), respectively. Based on the results of the meta-analysis also, risk values related to occupational and environmental exposures in summer were often higher than those in winter. These results can be used by policymaking to focus on decreasing exposure to BTEX, particularly in climatic conditions with higher hazards.