Odour as a determinant of persistent symptoms after a chemical explosion, a longitudinal study

Abstract

Foul-smelling environmental pollution was a major concern following a chemical workplace explosion. Malodorous pollution has previously been associated with aggravated physical and psychological health, and in persons affected by a trauma, an incidence-related odour can act as a traumatic reminder. Olfaction may even be of significance in the development and persistence of post-traumatic stress symptoms (PTSS). The present longitudinal study assessed whether perceived smell related to malodorous environmental pollution in the aftermath of the explosion was a determinant of subjective health complaints (SHC) and PTSS among gainfully employed adults, when the malodorous pollution was present, and after pollution clean-up. Questionnaire data from validated instruments were analysed using mixed effects models. Individual odour scores were computed, and the participants (n=486) were divided into high and low odour score groups, respectively. Participants in the high odour score group (n=233) reported more SHC and PTSS than those in the low odour score group (n=253), before and even after the pollution was eliminated. These associations lasted for at least three years after the pollution was removed, and might indicate that prompt clean-up is important to avoid persistent health effects after malodorous chemical spills.

Industrial odour pollution and human health: a systematic review and meta-analysis

“… Hayes 2017 [ 31 ], Australia, Cross-sectional Wastewater treatment Plant N = 153 residents within a 3-km radius on two exposed (with a history of high or low number of complaints) and one control sites Questionnaire (presence/absence of bad smells and odours impacting community) Questionnaire : Self-reported psychological symptoms past week; odour annoyance (10-point scale) Groups: Mood states Model: ANOVA Effect estimated : None Social readjustment scale by Holmes and Rahe 1967 added as covariate Tjalvin 2015 [ 32 ], Norway, Cross-sectional Chemical Industry (Chemical explosion in an Industrial harbour) N = 284 workers in 2008 and 203 in 2012 (exposed workers employed in 2008 and/or clean-up workers, proximity to the explosion ≤1 km; control workers) range of age 18–67 Questionnaire : Workers exposure history Subjective Health Complaints (SHC) score Groups : General ill feeling Gastrointestinal symptoms Upper respiratory symptoms Immune function Cardiovascular problems Model : Linear mixed effects models with random intercept and slope Effect estimated : Mean difference Age, gender, smoking habits, educational level. Tjalvin 2017 [ 33 ], Norway, cross-sectional (repeated survey of Tjalvin 2015) Chemical Industry (Chemical explosion in an Industrial harbour) N = 486 workers employed in 2008 (18% present during the explosion), in 2010 ( n = 379), 2012 ( n = 252) Adults aged 18–67 years Questionnaire : Low/high odour score (% of months each participant noticed the odour in 2008) Questionnaire : Subjective Health Complaints (SHC) score previous month; Impact of Event Scale-Revised (IES-R) previous 7 days Groups: General ill feeling Mood states Model : Linear mixed effects models with random intercept and slope Effect estimated : Mean difference Age, gender, smoking habits, educational level, absence/presence during the explosion (> 1 km or ≤ 1 km) Boers 2016 [ 34 ], Netherlands, Cross-sectional Animal feeding operations N = 582 residents living near livestock farms Mean age = 51 years old (SD 13) (part of the population included in Hooiveld 2015) Calculated exposure : 98th percentile of odour concentrations (OU E /m 3 ) from Stacks dispersion model Questionnaire : Self-reported odour annoyance (4-point scale) G...…”

“…symptoms, worsening of disease) and chronic outcomes (e.g. prevalence of diseases), with different timing of data collection, with past year prevalence in some studies [ 30 , 36 , 39 , 43 , 45 , 49 ] or past 2 years [ 37 , 40 ], or past 6 months prevalence [ 38 ], past 1 month [ 32 , 33 , 37 ], or current symptoms [ 9 , 29 , 31 , 34 , 42 , 43 , 45 , 47 ].…”

“…Most cross-sectional studies took into account the potential confounding of age, sex, smoking status, educational level and/or SES [ 32 , 33 , 35 – 39 , 41 – 45 ]. Panel studies [ 23 – 29 ] were adjusted only by time-varying variables (e.g.…”

“…3 ). Regarding the attrition bias, in 10 studies [ 25 , 26 , 32 , 33 , 36 , 40 , 45 , 46 , 48 , 49 ] and in the two Steinheider’s study sites [ 47 ] the information about loss of participants was unclear or incomplete, hence they were considered at “probably high” risk of attrition bias. Missing values related to outcome variables in the study were treated in the analysis.…”

“…Nineteen studies analysed general ill symptoms as health outcome of odour related effects [ 9 , 24 , 27 , 30 , 32 , 33 , 35 , 37 – 41 , 44 – 47 , 49 – 51 ] (Additional file 3 ). All studies were on adults.…”