Publication date: Jul 08, 2026
Benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene (BTEX) are released into the atmosphere from various sources and cause several long-term health problems, especially in metropolitan cities. This study used a C6-C12 analyzer with thermal desorption gas chromatography to measure ambient BTEX levels from January to May 2020, covering pre-lockdown (phase 0) and lockdown phases (I-IV) during COVID-19 pandemic in Ahmedabad, India. The average ƩBTEX concentration dropped from 40. 51 ug/m (before lockdown) to 7. 86 ug/m (during lockdown), with an ~ 81% reduction. Toluene showed the relatively less reduction of 76%, while benzene, ethylbenzene, and xylenes each decreased over 80%. The largest hazard quotient (HQ) reduction was observed from phase 0 to phase II, with a 93% and 79% reduction in benzene and toluene, respectively. The hazard index (HI) for BTEX compounds from phase 0 to phase IV was 5. 60E-01, 2. 40E-01, 4. 33E-02, 3. 73E-02, and 3. 12E-02, with significant drops in phases I and II. HQ showed the strongest correlation with HI across all phases, whereas the most significant HI reductions occurred during phase I (51. 52%) and phase II (85. 71%). The incremental lifetime cancer risk (ILCR) showed benzene’s cancer risk dropping 93. 07% compared to ethylbenzene’s 89. 4% from phase 0 to phase II. Later phases showed less reduction due to resumed activities. Many data points exceeded the definite risk threshold (1E-04). ILCR decreased to 4. 76E-06 by phase IV, a 95. 01% decline. Thus, present study demonstrates how lockdown measures reduced BTEX pollution and associated human health risks.
| Concepts | Keywords |
|---|---|
| 33e | Ahmedabad |
| Ahmedabad | BTEX |
| Benzene | COVID-19 lockdown |
| Lockdown | Health risk |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | COVID-19 |
| drug | DRUGBANK | Toluene |
| disease | MESH | cancer |