Table 4.
Summary of the results of the literature review of the combined effects of noise and physical agents
| Physical agents | The level of combined risk | Level of evidence | Effects | Comments | Study | |
|---|---|---|---|---|---|---|
| Quantitative | Qualitative | |||||
| Noise & lighting | Illuminance < 100 lux and exposure to Leq > 55 dBA | Potentiation | Low | Disturbance and cognitive impairments | Undesirable lighting quality and low illuminance exacerbate non-auditory effects of noise | [117], [118], [119], [120], [121], [122], [123], [124], [125], [126], and [127] |
| Noise & heat | Exposure to Leq > 65 dBA and wet bulb globus temperature > 24°C | Additive | Medium | Hypertension, metabolic syndrome | Heat aggravates noise-induced hypertension and impairs cognitive performance | [128], [129], [130], [131], [132], [133], [134], [135], and [136] |
| Noise & vibration | Exposure to Leq > 80 dBA and acceleration of V > 5 m/s2(auditory effects) − exposure to Leq > 65 dBA and acceleration of V > 0.5 m/s2(non-auditory effects) | Synergistic | High | Hearing loss, fatigue, annoyance, decreased performance | Vibration exacerbates all noise effects | [7], [14], [138],[139], [140], [141], [142], [143], [144], [145], [146]¸ [147], and [148]. |
| Noise & cold | Exposure to Leq > 80 dBA and dry temperature < 15°C | Likely additive | Low | Hearing loss, decreased performance | Combined effects of noise and cold deserve more studies in the future | [8], [140], and [150] |
Level of evidence: Level of evidence was determined based on the number of citations, methodological quality and design, validity, and applicability of studies results (Low − Medium − High). The Level of combined risk: The degree of effect intensification caused by the simultaneous presence of two factors or agents that was determined based on design and study type, the methodological, validity of data, and the study population. Additive effect: The combined effect produced by the action of two or more agents, being equal to the sum of their separate effects (2+2=4). Synergistic effects: An effect arising between two or more agents, or factors, that produces an effect greater than the sum of their individual effects (2 + 2 = 25). Potentiation effects: The combination of a factor or agent that has no effect (0) with a factor or agent that has effect (2) equal to the combined effect (10) greater than the sum of the effects of each one alone (0 + 2 = 10). Antagonism effects: Two or more combined agents have an overall effect that is less than the sum of their individual effects (5 + 0 = 2).